star

The only time it's safe to put a star atop your tree

esiegel — Tue, 24 Dec 2013 13:38:36 +0000

The only time it's safe to put a star atop your tree

"Bethany: Is your house on fire, Clark?
Clark: No, Aunt Bethany, those are the Christmas lights." -National Lampoon's Christmas Vacation

Ahh, Christmas. It's easy to forget how much the invention of the light bulb in 1879 reduced the number of tree fires in people's homes. It was a mere three years later that people began decorating Christmas trees with strings of lights instead of candle flames, and as you can imagine, the reduction in open flames atop fresh kindling had its benefits, and caught on like wildfire. Trees now routinely sport previously unfathomable numbers of lights, limited only by your imagination and your (optional) good taste.

Image credit: National Park Service, via http://nps.gov/.

But what about putting a star atop one of these trees?

I don't mean one of those pretend, cheap, Earth-built stars; I mean the real deal. You know, a star: a massive, luminous sphere of plasma held together by its own gravity and held up by a fantastic amount of outward radiation pressure!

Image credit: NASA's Goddard Space Flight Center / SDO.

And if you decide to put one of those on top of a tree... well... if something like this happens, it's your own fault!

Image credit: Andrew Walsh, aka flickr user radiofree.

But there is at least one place in our galaxy where it's not only safe but also beautiful to place a star atop your Christmas tree, and -- with the right equipment -- you can see it for yourself this holiday season. Shortly after sunset tonight and all through the majority of the coming winter nights, you can find the great winter constellation Orion. If you draw an imaginary line from the "highest" stars of the hunter -- Bellatrix to Betelgeuse and well beyond -- you'll eventually come to the prominent star Gomeisa, just a little north of the brilliant Procyon.

Image credit: me, using the free software Stellarium, via http://stellarium.org/.

Well, if you go to the place that's halfway between Gomeisa and Betelgeuse, you can move from that location towards ξ Geminorum, another prominent naked-eye star. And midway on your journey there, you can find the much less prominent (but still naked-eye) star S Monocerotis, a very (intrinsically) bright-and-blue star. If you view it through a telescope or very good binoculars, you should be able to find a spectacular sight for the holiday season: the Christmas Tree cluster!

Image credit: Alicia, aka flickr user capella_891.

Also known as NGC 2264, this collection of bright blue stars lies some 2,600 light-years away, and the very bright, blue star at the base is the aforementioned S Monocerotis, which is actually a supergiant variable star system some 8,000 times as luminous as the Sun! A rare O-class star -- the brightest and hottest of all stellar classes -- this will someday go supernova, likely outshining all other stars and planets in the night sky when it does.

It's also the base of the Christmas Tree, which has a beautiful blue star (HD 47887) and a little something extra as a tree-topper.

Image credit: Hap Griffin via http://www.machunter.org/hap_ngc2264.html.

The cluster is a collection of around 600 bright, new stars, and it's full of nebulosity in the form of neutral-and-ionized hydrogen, which gives it its characteristic combined blue-and-red hues. The ionized hydrogen, when it recombines to form neutral atoms, emits a characteristic red line at 656.3 nanometers, which explains the faint red hue. There's also some neutral dust that reflects the bright blue starlight of S Monocerotis, which is where the blue color comes from!

But you'll notice something unique at the top of the proverbial tree topper, and it's the other famous part about NGC 2264: the Cone Nebula!

Image credit: NASA, H. Ford (JHU), G. Illingworth (UCSC/LO), M.Clampin (STScI), G. Hartig (STScI), the ACS Science Team, and ESA.

This nebula is actually a molecular gas cloud giving rise to newly forming stars, in the process of being evaporated from the intense stellar heat both coming from the interior -- due to the protostars inside it -- as well as from the ultraviolet radiation coming from the surrounding young, hot stars!

There's also a much larger molecular cloud complex at work here, which observations that specifically look for the ionized hydrogen signature can really bring out spectacularly.

Image credit: T.A. Rector (NRAO/AUI/NSF and NOAO/AURA/NSF) and B.A. Wolpa (NOAO/AURA/NSF).

If you're having difficulty seeing the tree shape, I've taken the liberty of outlining it for you below using the ESO image featured at the beginning, below. (And if you really want an insanely large version, give this link a shot!)

Image credit: European Southern Observatory (ESO).

The most unique view you're likely to see, however, is one that your eyes will never pick up, and that's of what's present in the infrared! At wavelengths longer than the human eye can see, we find warm-and-cold dust, some of which is present in tendrils a mere hundred thousand years old!

Image credit: NASA / JPL-Caltech / P.S. Teixeira (CfA), MIPS / IRAC.

Can you find the tree-topper star and the Cone Nebula in there?

I've sifted through the image and pulled it out for you, and even though it's a glorious sight, the most surprising thing in there is not to be found in the nebula itself, but in the sheer number of stars and protostars actually present in this object, which clearly extends well into the thousands from views of this small region alone!

Image credit: NASA / JPL-Caltech / P.S. Teixeira (CfA), MIPS / IRAC.

So this Christmas, don't be afraid of putting an Earth-based star atop your tree, but if you've got aspirations for a real star atop one, do us all a favor and stick to the one atop the Christmas Tree cluster! Happy holidays, all, and I'll see you back here after Christmas!

esiegel Tue, 12/24/2013 - 08:38

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Astronomy

Physics

Random Stuff

Stars

Happy holidays Ethan, all the best!

Ethan rules!
Thank you!

Thanks for an excellent year of gems, Ethan.
Seasons greetings to all.

Messier Monday: The 'Little Sister' Cluster, M46

esiegel — Mon, 23 Dec 2013 17:03:47 +0000

Messier Monday: The 'Little Sister' Cluster, M46

"A sister is both your mirror - and your opposite." -Elizabeth Fishel

With 110 deep-sky wonders to choose from in the Messier catalogue, our long-running series on Messier Monday promises to keep us busy for some time to come! As we've finally passed the winter solstice here in the Northern Hemisphere, many new spectacular sights await skygazers in the early part of the night. As it's also the 1-year anniversary of when we adopted a little sister for our dog from the local humane society, I thought it would only be fitting to highlight the little sister to last week's Messier object.

Image credit: Greg Scheckler (http://gregscheckler.wordpress.com/blog/) with telescopy by Slooh.com.

Last week, we took a look at Messier 47, a relatively nearby, young open star cluster that rises shortly after sunset at this time of year, trailing a little bit behind Sirius, the brightest star in the night sky. But just a single degree away is this week's object -- Messier 46 -- which appears at first glance to be a dimmer, less spectacular 'sister' cluster.

Is that the truth? Let's show you how to discover it and then find out together!

Image credit: me, using the free software Stellarium, via http://stellarium.org/.

As we approach the new year, Orion can be seen flying higher in the sky earlier and earlier in the night, trailed by Sirius and -- a little bit later (and lower) -- the slightly more southerly bright pair Adhara and Wezen. Right next to Sirius is the quite bright (at magnitude +2) star Mirzam.

If you draw an imaginary line from Mirzam to Sirius and another from Adhara to Wezen and extend them both, where they meet is approximately where Messier 46 lies.

Image credit: me, using the free software Stellarium, via http://stellarium.org/.

There are really only about three stars in that small region that are clearly visible to the naked eye, but through binoculars or a telescope, there are quite a few deep-sky objects in that region of sky. This is no surprise for a location that looks into the galactic plane like this, and the dominant deep-sky object is last week's Messier 47. Just a little bit south of that cluster, however, between the naked-eye stars 4 Puppis and HIP 37379, lies a dimmer, smaller cluster: this week's object, Messier 46!

Image credit: me, using the free software Stellarium, via http://stellarium.org/.

It's easy to overlook this cluster when compared to the bright, blue beauties just to the north of it, but if you take a closer look at what might -- at first glance -- appear to be a non-spectacular object, you'll be glad that you did.

Image credit: W. Garrett Grainger, Jr. of http://www.beachastronomy.com/.

Standing out clearly against the galactic backdrop, these stars may all appear faint, but are they really? Messier described them so:

A cluster of very small stars, between the head of the Great Dog and the two hind feet of the Unicorn... one cannot see these stars but with a good refractor; the cluster contains a bit of nebulosity.

But even though Messier was wrong about this cluster in a whole slew of ways, it's easy to understand when you look back with 242 years of hindsight since its discovery.

Image credit: Kfir Simon of Pbase, at http://www.pbase.com/image/133973249.

Although it might seem wimpy compared to it's brighter sister cluster in the sky, Messier 46 isn't made up of small stars, nor does it have any nebulosity inside of it. Instead, it's one of the most distant open clusters in the Messier catalogue, located over 5,000 light-years away!

And one of the main reasons it appears to have so many stars prominently displayed in there is because the brightest classes of stars -- the O and B stars -- have all run through their entire life cycle and died by this point.

Image credit: Unknown, retrieved from http://www.docdb.net/show_object.php?id=ngc_2437.

That leaves a cluster dominated by A-class stars, which are still blue and bright, but much less so than its shorter-lived brethren. All clusters, when they're born, are thought to contain stars of all types, with the brightest and most massive stars running out of fuel fastest. From the stars that still remain in M46, we can tell it's about 300 million years old, an intermediate age for a star cluster.

A closer inspection -- one that brings out more colors and the fainter stars -- can reveal that there are around 500 stars identifiable in this cluster, including many that are dimmer and redder (in addition to a small number of giant stars) than the Sirius-like A-stars.

Image credit: Roy Uyematsu of http://www.roystarman.com/.

There could, of course, be even more stars located in this 26-light-year-wide spherical region; infrared observations -- as they often do -- highlight a somewhat different stellar population than what we see with visible light images.

Image credit: Two-Micron All-Sky Survey (2MASS) / IPAC.

In addition, you may be noticing what looks like a familiar shape: a ringed nebula around one of the stars! In fact, there is a planetary nebula there, a remnant of a dying sun-like star going through its death throes, blowing off its outer layers and contracting its core down to a white dwarf.

But, is it connected to the cluster, or is it merely a foreground object?

Image credit: Daniel López, IAC.

It's hard to tell from just the optical image, isn't it? Although you might intuit that the apparent reddening of stars around the planetary nebula is indicative that the stars are behind the nebula, that doesn't tell you whether this is a foreground object or whether this nebula is merely towards the "near side" of the cluster.

If we want to know for sure, we have to measure the redshift of many individual stars and the planetary nebula.

Image credit: Canada-France-Hawaii Telescope/Coelum Observatory.

You see, open star clusters are very tenuously bound, and stars contained inside one all have approximately the same redshift, as even small changes in a star's velocity would cause it to escape from the cluster. Well, the stars in the cluster are receding from us at 41.4 km/sec, but the nebula recedes at 77 km/sec, so it's not a part of the cluster after all!

Our best estimates, in fact, place it at a mere 2,900 light-years distant, much less than the estimated 5,400 of today's cluster!

Image credit: Wikimedia Commons user Fabian RRRR, via the Hubble Legacy Archive (ESA/NASA).

The shame of the more distant star clusters is that they're often obscured by the disk of the galaxy, and that it's increasingly more difficult to bring out the fine details in them. But, it is easier to fit the entire cluster into a high-magnification field-of-view, which makes it very easy to view the entire thing at once!

This cluster is large, massive, and has all the right ingredients to make it to a billion years or more intact, a bonafide rarity for an open star cluster! Enjoy this less well-known sight all winter long, but feel free to start today, as we wrap up the year's penultimate Messier Monday! Including today, we’ve looked at the following objects:

M1, The Crab Nebula: October 22, 2012
M2, Messier’s First Globular Cluster: June 17, 2013
M5, A Hyper-Smooth Globular Cluster: May 20, 2013
M7, The Most Southerly Messier Object: July 8, 2013
M8, The Lagoon Nebula: November 5, 2012
M11, The Wild Duck Cluster: September 9, 2013
M12, The Top-Heavy Gumball Globular: August 26, 2013
M13, The Great Globular Cluster in Hercules: December 31, 2012
M15, An Ancient Globular Cluster: November 12, 2012
M18, A Well-Hidden, Young Star Cluster: August 5, 2013
M20, The Youngest Star-Forming Region, The Trifid Nebula: May 6, 2013
M21, A Baby Open Cluster in the Galactic Plane: June 24, 2013
M25, A Dusty Open Cluster for Everyone: April 8, 2013
M29, A Young Open Cluster in the Summer Triangle: June 3, 2013
M30, A Straggling Globular Cluster: November 26, 2012
M31, Andromeda, the Object that Opened Up the Universe: September 2, 2013
M32, The Smallest Messier Galaxy: November 4, 2013
M33, The Triangulum Galaxy: February 25, 2013
M34, A Bright, Close Delight of the Winter Skies: October 14, 2013
M36, A High-Flying Cluster in the Winter Skies: November 18, 2013
M37, A Rich Open Star Cluster: December 3, 2012
M38, A Real-Life Pi-in-the-Sky Cluster: April 29, 2013
M39, The Closest Messier Original: November 11, 2013
M40, Messier’s Greatest Mistake: April 1, 2013
M41, The Dog Star’s Secret Neighbor: January 7, 2013
M44, The Beehive Cluster / Praesepe: December 24, 2012
M45, The Pleiades: October 29, 2012
M46, The 'Little Sister' Cluster: December 23, 2013
M47, A Big, Blue, Bright Baby Cluster: December 16, 2013
M48, A Lost-and-Found Star Cluster: February 11, 2013
M50, Brilliant Stars for a Winter’s Night: December 2, 2013
M51, The Whirlpool Galaxy: April 15th, 2013
M52, A Star Cluster on the Bubble: March 4, 2013
M53, The Most Northern Galactic Globular: February 18, 2013
M56, The Methuselah of Messier Objects: August 12, 2013
M57, The Ring Nebula: July 1, 2013
M60, The Gateway Galaxy to Virgo: February 4, 2013
M65, The First Messier Supernova of 2013: March 25, 2013
M67, Messier’s Oldest Open Cluster: January 14, 2013
M71, A Very Unusual Globular Cluster: July 15, 2013
M72, A Diffuse, Distant Globular at the End-of-the-Marathon: March 18, 2013
M73, A Four-Star Controversy Resolved: October 21, 2013
M74, The Phantom Galaxy at the Beginning-of-the-Marathon: March 11, 2013
M75, The Most Concentrated Messier Globular: September 23, 2013
M77, A Secretly Active Spiral Galaxy: October 7, 2013
M78, A Reflection Nebula: December 10, 2012
M79, A Cluster Beyond Our Galaxy: November 25, 2013
M81, Bode’s Galaxy: November 19, 2012
M82, The Cigar Galaxy: May 13, 2013
M83, The Southern Pinwheel Galaxy, January 21, 2013
M86, The Most Blueshifted Messier Object, June 10, 2013
M92, The Second Greatest Globular in Hercules, April 22, 2013
M94, A double-ringed mystery galaxy, August 19, 2013
M97, The Owl Nebula, January 28, 2013
M99, The Great Pinwheel of Virgo, July 29, 2013
M101, The Pinwheel Galaxy, October 28, 2013
M102, A Great Galactic Controversy: December 17, 2012
M103, The Last ‘Original’ Object: September 16, 2013
M104, The Sombrero Galaxy: May 27, 2013
M106, A Spiral with an Active Black Hole: December 9, 2013
M108, A Galactic Sliver in the Big Dipper: July 22, 2013
M109, The Farthest Messier Spiral: September 30, 2013

Come back next week, where another deep-sky wonder -- and another tale that the Universe tells us about itself -- awaits you, only on Messier Monday at Starts With A Bang!

esiegel Mon, 12/23/2013 - 12:03

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Messier Monday: A High-Flying Cluster in the Winter Skies, M36

esiegel — Mon, 18 Nov 2013 18:32:31 +0000

Messier Monday: A High-Flying Cluster in the Winter Skies, M36

“Once you have tasted flight, you will forever walk the Earth with your eyes turned skyward, for there you have been, and there you will always long to return.” -Leonardo da Vinci

Welcome back to another exciting Messier Monday here on Starts With A Bang! As Comet ISON dives towards the Sun and a nearly perfect full Moon towers overhead, it's easy to forget about those wondrous deep-sky objects that are fixed, but the 110 prominent members of the Messier Catalogue are always on tap for dedicated skywatchers. Although the extended objects -- galaxies and nebulae -- are difficult to view with a bright Moon out, the star clusters, both open clusters and globulars, still make for spectacular viewing.

Image credit: Rolando Ligustri, via http://itelescope.net/.

Today, we're going to highlight one of the dimmer (and thus, often overlooked) open star clusters of the Messier Catalogue, still clearly visible with even a small telescope or binoculars, provided you know where to look: Messier 36. For those of you who are night owls with clear skies, you may have noticed the recent appearance of the famed winter constellation Orion; that will be your guide to finding this week's Messier object.

Image credit: me, using the free software Stellarium, available at http://stellarium.org/.

The Moon is famous among skywatchers for not only being a towering, brilliant source of light, but also for being a terrible source of light pollution. Tonight's practically full Moon means that the night sky's immediate vicinity around it at a total wilderness site is about as polluted as the night sky in a downtown urban area of a large (Seattle-sized) city. But that doesn't mean you can't still see the absolute brightest stars; Orion rises at around 9 PM over the Eastern horizon and even farther above it is the constellation of Auriga, heralded by brilliant Capella, the third brightest star in the entire Northern Hemisphere, behind only Arcturus and Vega.

Image credit: me, using the free software Stellarium, available at http://stellarium.org/.

Auriga makes an oval-like shape, with bright blue Alnath on the narrow end, opposite Capella and Menkalinan. (Alnath is technically in the constellation of Taurus, but it's by less than a single degree; I'm far from the only one who always thinks of it as part of Auriga.) If you draw an imaginary line from Alnath back towards Menkalinan, you'll come to the naked eye star χ Aurigae, which should still be visible even with the full Moon nearby.

And if you navigate from Alnath to χ Aurigae and head just a little bit farther in that same direction, you won't be able to miss a very nice cluster of stars -- Messier 36 -- in either a telescope or binoculars.

Image credit: me, using the free software Stellarium, available at http://stellarium.org/.

This open star cluster is often challenging if you don't know where to look, as it takes up a very small region on the sky (just a fifth of a degree) and is invisible to the naked eye under ideal dark-sky conditions. Nevertheless, it had been known for more than century before Messier catalogued it, noting it as a:

Cluster of stars in Auriga, near the star Phi: with an ordinary telescope... one has pain to distinguish the stars, the cluster contains no nebulosity.

And if you viewed it in an instrument of Messier's power, you might well reach the same conclusion.

Image credit: Bill Longo, via http://billlongo.com/messier36.php.

It seems like it barely stands out at all against the backdrop of other stars of similar magnitude. But what appears to be a small and unspectacular collection of dim stars from our point of view is actually an incredible sight, if we're willing to take a look inside.

Image credit: Andy E. Rostron of http://nightcamera.blogspot.com/.

A glittering array of mostly blue stars that's quite concentrated, Messier 36 has two particularly bright stars located at its center. Although they might not have stood out to Messier, even a 3" (80 mm) telescope is good enough to see that brilliant central pair!

And if you're willing to dive in with a really high-quality telescope, you can find out a whole lot more!

A quite young cluster with no red giant stars inside, the bluest star found in Messier 36 is of spectral class B2, just barely below the threshold of stars that end their lives in supernovae!

The reason this cluster appears so small and faint is because it's so far away; at a distance of 4,100 light years it's one of the top-10 most distant Messier open clusters, some ten times as far away as the Pleiades. At its current distance, it's 14 light years in diameter, making it almost the same physical size as the Pleiades, and based on the stars we find in there, it's only 25 million years old; our Sun is nearly 200 times older!

At least 60 individual stars have been identified in this cluster, although it's easily conceivable that there are hundreds -- if not as many as a thousand -- in there that are simply hidden from our view thus far. It's no wonder; like most open star clusters, Messier 36 is indeed located right in the galactic plane!

Still, you might ask yourself whether there was anything interesting to learn in the infrared. Is there dust? Red stars simply invisible to our visible eyes? Something else?

Image credit: Two Micron All-Sky Survey (2MASS).

It looks like -- if you didn't know better -- a shooting, red star is in there, doesn't it?

What's amazing is that, to the best we've been able to tell, there really is something interesting in there!

Image credit: NOAO / AURA / NSF.

What is that thing? If only there were a better image to find out! In the meantime, this is the best I've been able to find!

Image credit: NOAO / AURA / NSF.

It looks like a star whipping through the interstellar medium so quickly it's grown a tail, similar to the well-known star Mira, but until better data comes along, it will have to remain a mystery! With that said, it's a great sight for now and all through the entire winter, even when the Moon is at its brightest! And that will have to wrap up another Messier Monday! Including today’s entry, we’ve explored at the following Messier objects:

M1, The Crab Nebula: October 22, 2012
M2, Messier’s First Globular Cluster: June 17, 2013
M5, A Hyper-Smooth Globular Cluster: May 20, 2013
M7, The Most Southerly Messier Object: July 8, 2013
M8, The Lagoon Nebula: November 5, 2012
M11, The Wild Duck Cluster: September 9, 2013
M12, The Top-Heavy Gumball Globular: August 26, 2013
M13, The Great Globular Cluster in Hercules: December 31, 2012
M15, An Ancient Globular Cluster: November 12, 2012
M18, A Well-Hidden, Young Star Cluster: August 5, 2013
M20, The Youngest Star-Forming Region, The Trifid Nebula: May 6, 2013
M21, A Baby Open Cluster in the Galactic Plane: June 24, 2013
M25, A Dusty Open Cluster for Everyone: April 8, 2013
M29, A Young Open Cluster in the Summer Triangle: June 3, 2013
M30, A Straggling Globular Cluster: November 26, 2012
M31, Andromeda, the Object that Opened Up the Universe: September 2, 2013
M32, The Smallest Messier Galaxy: November 4, 2013
M33, The Triangulum Galaxy: February 25, 2013
M34, A Bright, Close Delight of the Winter Skies: October 14, 2013
M36, A High-Flying Cluster in the Winter Skies: November 18, 2013
M37, A Rich Open Star Cluster: December 3, 2012
M38, A Real-Life Pi-in-the-Sky Cluster: April 29, 2013
M39, The Closest Messier Original: November 11, 2013
M40, Messier’s Greatest Mistake: April 1, 2013
M41, The Dog Star’s Secret Neighbor: January 7, 2013
M44, The Beehive Cluster / Praesepe: December 24, 2012
M45, The Pleiades: October 29, 2012
M48, A Lost-and-Found Star Cluster: February 11, 2013
M51, The Whirlpool Galaxy: April 15th, 2013
M52, A Star Cluster on the Bubble: March 4, 2013
M53, The Most Northern Galactic Globular: February 18, 2013
M56, The Methuselah of Messier Objects: August 12, 2013
M57, The Ring Nebula: July 1, 2013
M60, The Gateway Galaxy to Virgo: February 4, 2013
M65, The First Messier Supernova of 2013: March 25, 2013
M67, Messier’s Oldest Open Cluster: January 14, 2013
M71, A Very Unusual Globular Cluster: July 15, 2013
M72, A Diffuse, Distant Globular at the End-of-the-Marathon: March 18, 2013
M73, A Four-Star Controversy Resolved: October 21, 2013
M74, The Phantom Galaxy at the Beginning-of-the-Marathon: March 11, 2013
M75, The Most Concentrated Messier Globular: September 23, 2013
M77, A Secretly Active Spiral Galaxy: October 7, 2013
M78, A Reflection Nebula: December 10, 2012
M81, Bode’s Galaxy: November 19, 2012
M82, The Cigar Galaxy: May 13, 2013
M83, The Southern Pinwheel Galaxy, January 21, 2013
M86, The Most Blueshifted Messier Object, June 10, 2013
M92, The Second Greatest Globular in Hercules, April 22, 2013
M94, A double-ringed mystery galaxy, August 19, 2013
M97, The Owl Nebula, January 28, 2013
M99, The Great Pinwheel of Virgo, July 29, 2013
M101, The Pinwheel Galaxy, October 28, 2013
M102, A Great Galactic Controversy: December 17, 2012
M103, The Last ‘Original’ Object: September 16, 2013
M104, The Sombrero Galaxy: May 27, 2013
M108, A Galactic Sliver in the Big Dipper: July 22, 2013
M109, The Farthest Messier Spiral: September 30, 2013

Come back next week, where another deep-sky object — and another unique story about the Universe — awaits you here, only on Messier Monday!

esiegel Mon, 11/18/2013 - 13:32

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"t looks like a star whipping through the interstellar medium so quickly it’s grown a tail,"

Very comet-like.
Like Mira's tail but also like a comet.

If only there were a better image to find out! In the meantime, this is the best I’ve been able to find!

I presume the images were from different nights and same place thus not a comet or temporary object, right? No dates on the images there that I can see.

Certainly intriguing & would be great to discover its identity and details.

We are looking outward to the Perseus arm, so it is conceivable that this is a galaxy. But my money is on a red giant star in the line of site of a more distant nebula.

It's hard to be sure what that is, but it could be a local M dwarf which is being ejected from the cluster--that would account for its high velocity with respect to the local interstellar medium. And since the ejection would be recent (by cosmological standards), the tail would not have had much time to grow.

wow. interesting. could it be final stages of 2 stars merging?

or a black hole chucking some large chunks and some are ejected on the pole? a wish perhaps :)

It's just an exclamation point put there by the universe so the Hubble takes a look and lets us admire its beauty :)

Hey everyone, just wanted to give you a heads-up that you should say what you need to say over the next six hours or so here.

The site is undergoing maintenance / migration tomorrow, and may be down for extended periods of time. As such, I won't be able to post and you likely won't be able to comment until the end of the day Wednesday at the earliest. Sorry for the inconvenience, but hopefully all the loading / slowness issues we've experienced over the past couple of months will be a thing of the past.

See you back here soon; thanks for being such an excellent community!

@ ^ Ethan : Thanks for the warning.

A few more thoughts on our mystery red comet-like object here. (Like some of the other ideas here too.)

1. Could it be a proplyd (protoplanetary disk) that's "evapourating" / being blown away (photodissociation the term maybe?) by nearby hot massive stars - just like some proplyds in the Orion nebula?

Of course we can't really see any bright stars nearby and the tail doesn't seem to be pointing away from any but maybe there's one hidden from us by thick dust there - too thick even for the 2MASS, NOAO / AURA / NSF to reveal? Okay perhaps a bit unlikely.

2. Maybe its a young T-Tauri / FU Orionis type star illuminating a surrounding nebula like Hubble's Variable nebula (NGC 2261) that actually seems reasonably plausible and matching , perhaps making this one of the very last of the stars to form in M36?

3. Or what about a protoplanetary nebula or micro-quasar :

http://en.wikipedia.org/wiki/Microquasar#Microquasar

that's seen from an odd angle or suchlike?

What we really need is a spectrum of it! Don't know if anyone here is able to get one of it or more images?

I like some of the other suggestions here such as a background galaxy too. Occurs to me that a distant nebula could also be another possible explanation.

Without more information its going to be really hard to do more than brainstorms such suggestions. More data please!

PS. For comparison of this object with Hubble's Variable nebula (NGC 2261) see :

http://www.spacetelescope.org/images/opo9935c/

note the star at the centre is R Monocerotis in case that helps with searching. Plenty of other images for that should be findable too.

A spectrum, a spectrum my (oh I dunno, looks around) .. cup of tea for a spectrum! ;-)

(With apologies to Shakespeare, King Richard III.)

This object has been studied before. I used MAST

http://archive.stsci.edu/

to find HST observations, which led me via ADS

http://adsabs.harvard.edu/abstract_service.html

to a paper by Magnier et al.

http://adsabs.harvard.edu/abs/2013AJ....146...49M

The bottom line is: the object is a young star making the transition from Class 1 to Class 2; that means that the accretion disk is shrinking from "comparable to the central star in mass" to "much less than the central star in mass".

As #10 M Richmond noted, the object appears to be a Young Stellar Object known as IRAS 05327+3404 (aka "Holoea", Hawaiian for 'flowing gas') discovered by Magnier et. al. in 1996. Further studies of this object, with a K2 spectrum and possibly associated with the nearby star-forming region Sh2-235, can be found here:

http://cdsads.u-strasbg.fr/cgi-bin/nph-bib_query?1999A%26A...346..441M&…

http://arxiv.org/abs/1305.6550

Messier Monday: The Closest Messier Original, M39

esiegel — Mon, 11 Nov 2013 18:02:20 +0000

Messier Monday: The Closest Messier Original, M39

"Books serve to show a man that those original thoughts of his aren't very new at all." -Abraham Lincoln

It might be Veterans Day / Armistice Day all around the world, but it's still Messier Monday here on Starts With A Bang! We may have been fighting wars for all of human history, but nearly all of the 110 deep sky objects that make up the Messier Catalogue go back long before that.

Image credit: Tenho Tuomi of Tuomi Observatory, via http://www.lex.sk.ca/.

Today, we take an in-depth look at one of the brightest and closest star clusters in the entire night sky, one that -- despite being visible to the naked eye -- went unrecorded until Messier himself catalogued it in 1764. Let's take a tour of Messier 39, starting with how to find it.

Image credit: me, using the free software Stellarium, via http://stellarium.org/.

Although one of the most prominent collections of stars in the night sky is known as the Summer Triangle -- consisting of the dominant stars (in its portion of the sky) Altair, Deneb and Vega -- it's actually visible after sunset well into autumn and even early winter for the Northern Hemisphere! The galactic plane passes through the summer triangle, and most of the open star clusters contained within our galaxy are found in the galactic plane, and Messier 39 is no exception to this rule.

To find it, draw an imaginary line from Vega (the brightest one) to Deneb (on the short side with Vega), and continue to head a little farther in that same direction.

Image credit: me, using the free software Stellarium, via http://stellarium.org/.

The first thing you'll run into is the easily visible naked-eye star, the orange supergiant ξ Cygni, which is nearly along the imaginary line extended along the Vega-to-Deneb path. If you think about Deneb as the bottom of a circle and move clockwise towards ξ Cygni, you'll hit three more (albeit slightly dimmer) naked eye stars as you reach the top of the circle -- ρ Cygni, π² Cygni, and Azelfafage (also π¹ Cygni), in order -- and Messier 39 lies just inside of them.

Image credit: me, using the free software Stellarium, via http://stellarium.org/.

Although Messier, discovering it in 1764, gave it the very terse description:

Cluster of stars near the tail of the Swan; one can see them with an ordinary telescope...

this actually turns out to be one of the most remarkable objects in his entire catalogue! Let's take a look inside.

Image credit: John (J.C.) Mirtle of http://www.astrofoto.ca/.

You might first notice the prominent blue stars, and you should: there are about 30 prominent, blue-colored stars identified in M39, the bluest of which is of spectral type A0, the brightest and bluest of all the A-class stars. But one of the things that makes this cluster particularly interesting is that all of the bright stars are blue!

Image credit: Marcin Paciorek of http://www.astromarcin.pl/.

There are no red, orange or yellow giants, no prominent subgiants, and no stars in general found off of the main sequence!

For those of you who need a reminder, the main sequence is the line on which -- if you plot the colors vs. magnitudes of stars -- you'll find all stars burning hydrogen in their core.

Image credit: European Southern Observatory (ESO).

This is exceedingly rare! By this point in a star cluster's life, a star running out of fuel in its core takes some tens of millions of years to go from the main sequence and through the various subgiant and giant stages until it dies in a planetary nebula and white dwarf combination. With hundreds of stars expected in a typical star cluster, finding one without a single evolved star is exceedingly rare!

And yet, here Messier 39 is, doing exactly that.

Image credit: Jim Mazur's Astrophotography, via http://www.skyledge.net/.

With the background stars of the galaxy shining in a dim haze behind it, Messier 39 happens to be close, at a distance of just 800 light years, only the Pleiades and Praesepe star clusters are closer objects in the Messier catalogue. And yet, if we take a long exposure to really bring out the background stars, we don't really find many more that appear to be associated with these bright, blue ones! Even though -- based on what we see -- there are around 800 solar masses worth of material in there, we've only definitively identified around 60 stars in this cluster!

Image credit: Tonk of Cloudy Nights, via http://www.cloudynights.com/.

Only six of Messier's star clusters appear brighter to the eye, and the brightest of the blue stars here are just barely beyond the limit of human naked-eye vision under the darkest possible skies.

With long-exposure photography, the sight is nothing short of spectacular.

Based on the stars that are in there -- and assuming that higher mass ones are missing because they've evolved and disappeared -- we can estimate that this star cluster is around 300 million years old, but there are some uncertainties there.

After all, looking among what appear to be background stars, how many evolved white dwarfs from long-dead O-and-B-class stars are hanging out, invisible because of the incredible density of stars found in the galactic plane?

Image credit: flickr user The Killer Rabbit1.

You'd be very, very smart if you thought to look in the infrared; oftentimes, evolved, cooler stars that are less prominent in the visible will appear bright in the infrared!

Let's have a look at the best IR image out there of M39, thanks to 2MASS!

Image credit: The Two Micron All Sky Survey (2MASS) at IPAC.

This infrared image is what allowed us to go from about 30 (visible) stars up to around 60, but that's still a tiny number for an open star cluster! (And it's only seven light-years across; this star cluster would appear tiny if it weren't so ridiculously close!) Did something happen when this cluster was forming to end star formation early? It wouldn't be the only cluster like this, but the more of these objects I go through, the more of an appreciation I have for the sheer diversity of populations of stars that form naturally in the Universe!

My favorite of all the images that exist of M39 comes courtesy of NOAO, the National Optical Astronomy Observatories.

Image credits: Heidi Schweiker, WIYN, AURA, NSF, NOAO.

This image -- originally -- comes in an incredibly high resolution; if we take a "slice" through the center, here's what this incomparable star cluster looks like, silhouetted against the backdrop of the galactic plane!

Image credits: Heidi Schweiker, WIYN, AURA, NSF, NOAO.

This would make a lousy target for Hubble due to its incredibly large angular size, but that makes it all the more amazing as a target for amateur skygazers! And with that magnificent tour through one of the closest star clusters to us, that will wrap up another Messier Monday! Including today's entry, we've peered at the following Messier objects:

M1, The Crab Nebula: October 22, 2012
M2, Messier’s First Globular Cluster: June 17, 2013
M5, A Hyper-Smooth Globular Cluster: May 20, 2013
M7, The Most Southerly Messier Object: July 8, 2013
M8, The Lagoon Nebula: November 5, 2012
M11, The Wild Duck Cluster: September 9, 2013
M12, The Top-Heavy Gumball Globular: August 26, 2013
M13, The Great Globular Cluster in Hercules: December 31, 2012
M15, An Ancient Globular Cluster: November 12, 2012
M18, A Well-Hidden, Young Star Cluster: August 5, 2013
M20, The Youngest Star-Forming Region, The Trifid Nebula: May 6, 2013
M21, A Baby Open Cluster in the Galactic Plane: June 24, 2013
M25, A Dusty Open Cluster for Everyone: April 8, 2013
M29, A Young Open Cluster in the Summer Triangle: June 3, 2013
M30, A Straggling Globular Cluster: November 26, 2012
M31, Andromeda, the Object that Opened Up the Universe: September 2, 2013
M32, The Smallest Messier Galaxy: November 4, 2013
M33, The Triangulum Galaxy: February 25, 2013
M34, A Bright, Close Delight of the Winter Skies: October 14, 2013
M37, A Rich Open Star Cluster: December 3, 2012
M38, A Real-Life Pi-in-the-Sky Cluster: April 29, 2013
M39, The Closest Messier Original: November 11, 2013
M40, Messier’s Greatest Mistake: April 1, 2013
M41, The Dog Star’s Secret Neighbor: January 7, 2013
M44, The Beehive Cluster / Praesepe: December 24, 2012
M45, The Pleiades: October 29, 2012
M48, A Lost-and-Found Star Cluster: February 11, 2013
M51, The Whirlpool Galaxy: April 15th, 2013
M52, A Star Cluster on the Bubble: March 4, 2013
M53, The Most Northern Galactic Globular: February 18, 2013
M56, The Methuselah of Messier Objects: August 12, 2013
M57, The Ring Nebula: July 1, 2013
M60, The Gateway Galaxy to Virgo: February 4, 2013
M65, The First Messier Supernova of 2013: March 25, 2013
M67, Messier’s Oldest Open Cluster: January 14, 2013
M71, A Very Unusual Globular Cluster: July 15, 2013
M72, A Diffuse, Distant Globular at the End-of-the-Marathon: March 18, 2013
M73, A Four-Star Controversy Resolved: October 21, 2013
M74, The Phantom Galaxy at the Beginning-of-the-Marathon: March 11, 2013
M75, The Most Concentrated Messier Globular: September 23, 2013
M77, A Secretly Active Spiral Galaxy: October 7, 2013
M78, A Reflection Nebula: December 10, 2012
M81, Bode’s Galaxy: November 19, 2012
M82, The Cigar Galaxy: May 13, 2013
M83, The Southern Pinwheel Galaxy, January 21, 2013
M86, The Most Blueshifted Messier Object, June 10, 2013
M92, The Second Greatest Globular in Hercules, April 22, 2013
M94, A double-ringed mystery galaxy, August 19, 2013
M97, The Owl Nebula, January 28, 2013
M99, The Great Pinwheel of Virgo, July 29, 2013
M101, The Pinwheel Galaxy, October 28, 2013
M102, A Great Galactic Controversy: December 17, 2012
M103, The Last ‘Original’ Object: September 16, 2013
M104, The Sombrero Galaxy: May 27, 2013
M108, A Galactic Sliver in the Big Dipper: July 22, 2013
M109, The Farthest Messier Spiral: September 30, 2013

Come back next week, where another deep-sky object -- and another unique story about the Universe -- awaits you on Messier Monday!

esiegel Mon, 11/11/2013 - 13:02

Tags

" there are about 30 prominent, blue-colored stars identified in M39, the bluest of which is of spectral type A0, the brightest and bluest of all the A-class stars. "

For comparison, Vega is spectral class A0 (V or main sequence Sirian* dwarf)) and Sirius is spectral class A1 with other bright nearby A type main sequence Sirian* dwarf stars including Altair, Fomalhaut and four of the six stars making up Castor too.

Interestingly, Vega looks bluer and hotter than it really is because we see it pole-on :

http://en.wikipedia.org/wiki/Vega#Rotation

and thus at its hottest and bluest view.

I wonder whether any of the bright blue stars in M39 are similarly seen at their bluest and hottest angle and if so how many of them?

* Sirian used because "white dwarf" means something else entirely.

Isn't it Sirius B that is the dwarf star.

When colloquially called, the dwarf one is called "Sirius" too, but the visible one is not the dwarf.

But Sirius A is a main sequence, not dwarf.

They're using "dwarf" in the sense that is equivalent to "main sequence", or luminosity class V.

No idea what a "Sirian dwarf" is supposed to be, other than an invention to avoid confusion with the other, more commonly used meanings of "dwarf".

Which is just another reason why this sense of "dwarf" should be deprecated. Just say "main sequence".

Question here!
There are around 60 stars in this cluster. In the images, there are hundreds of stars within the confines of the obvious blue stars. How do we know which are in the cluster, and which are foreground/background stars. Has someone mapped the blue/red shifts of all the stars in the image? That would be impressive.

Google Hipparchos, Phil.

CB, Sirius has a white dwarf companion, Sirius B.

More confusion may arise because the Romans called Sirius (the visible one) "The little dog".

Yeah, I know, but there is only one sense in which Vega is a dwarf of any kind, and it's in the sense of "main sequence star", which they said, and also specified class V. Which is two ways in which that sense of "dwarf" is redundant.

But yeah, given the existence of Sirius B, using "Sirian dwarf" to *avoid* confusion with other meanings of "dwarf" is itself a confusing choice.

Vega is in Lyra, not Canis Majoris.

:-)

StevoR called both Vega and Sirius a "Sirian dwarf", aka "main sequence" aka "class V". The fact that they called Vega a dwarf (and also those other things in the same parenthetical) makes it fully clear that they did mean "dwarf" in the sense of "main sequence" which means they were not talking about Sirius B, because Sirius B is not the same kind of dwarf they were talking about.

To make it even more clear, Sirius B is a white dwarf and they specifically said they were not talking about white dwarfs.

So that's it. They were not talking about Sirius B because they were using a confusing (but real) definition of "dwarf".

I don't see what the location of Vega has to do with anything.

No, Steve was trying to shoehorn the same bullshit "argument" for Pluto to be a planet in here.

Pretty damn obvious, really.

The point of Vega was that I was talking about Sirius, not Vega, so there's no point of Vega, despite you bringing it up.

My point with Sirius was regarding the bunk claim of "sirian dwarf", the only match I see is for a fucking *Hamster*, was refutable and retarded.

They brought up Vega, not me, and in so doing made it perfectly clear what kind of dwarf they were talking about. Also they brought up Altair, Fomalhaut, also main-sequence class-V dwarfs.

But you want to talk Sirius. Okay. They were talking about Sirius A, not Sirius B. Sirius B is the white dwarf in the system, not the dwarf. Sirius A is the dwarf.

Except the point is that there's no such classification as "Sirian dwarf".

The only dwarf there is the white dwarf companion.

There's no such thing in astronomy as "Sirian Dwarf".

Also to be clear, "Sirian dwarf" wasn't a "claim". It was an attempt to make what definition of dwarf they were using more clear by distinguishing it from white dwarf.

Obviously it didn't work, and the failure is just a sign that this definition should be deprecated. Nevertheless it is technically correct to call Sirius A a dwarf, just like it is Sol.

"Sirian dwarf" isn't a thing in astronomy, they weren't claiming it was, they made it perfectly clear why they added that phrase (even if it didn't work).

"Dwarf" is a thing, and Sirius A is the dwarf.

Sirius B is the white dwarf.

"“Sirian dwarf” isn’t a thing in astronomy, they weren’t claiming it was, they made it perfectly clear"

Really?

What "they" are you wibbling on about, then?

Because Steve did no such thing.

There is no such thing as Sirian Dwarf unless you're into hamsters.

"Also to be clear, “Sirian dwarf” wasn’t a “claim”. It was an attempt to make what definition of dwarf they were using more clear by distinguishing it from white dwarf."

How about not making up a bullshit claim? Why was there an attempt to make a definition of dwarf that had absolutely no purpose other than to require that definition?

They didn't make a claim. And they didn't make a definition of dwarf, they tried to clarify an already-existing definition of dwarf (and failed). That definition of "dwarf" meaning "main-sequence" already exists.

Sirius A, Vega, Fomalhaut, and Sol are all dwarfs. That is valid terminology.

"They didn’t make a claim."

What definition of claim are you making here?

claim:5. A statement of something as a fact; an assertion of truth

Claim made: Vega is known as a Sirian Dwarf.

"Sirius A, Vega, Fomalhaut, and Sol are all dwarfs."

None of them are "Sirian Dwarfs". That is invalid terminology.

They did not claim it was known as that, they said they were using "Sirian" to distinguish "dwarf" from "white dwarf", the point of explaining such is that it *isn't* known that way. That attempt failed, partly because dwarf terminology is just confusing, partly because 'Sirian' is a confusing adjective to try to use for purpose of clarifying this case, and partly because you were unaware of the definition of "dwarf" they were trying to clarify in the first place so you didn't have the basis to understand what they were clarifying.

But as long as you now understand that you were wrong every time you said that the only dwarf in the system is Sirius B, because actually Sirius A is the dwarf (== main sequence == class V), while Sirius B is a white dwarf which is different, then I consider my contribution to this conversation done.

Please continue to berate StevoR for "claiming" that Vega is a Sirian Dwarf at your pleasure.

"They did not claim it was known as that"

No, he did.

@Wow

uh - WOW. the wikipedia entry for Hipparchos is kind of astounding. An astronomic education in itself. Definitely a sip from the fire hose.

:-)

It gets tiresome sometimes.

+1 CB

TWNLAA, Greg23.

-42.

"and partly because you were unaware of the definition of “dwarf” they were trying to clarify in the first place "

U gets one internets for fail, CB.

Messier Monday: The Last 'Original' Object, M103

esiegel — Mon, 16 Sep 2013 16:02:31 +0000

Messier Monday: The Last 'Original' Object, M103

"Now, this is not the end. It is not even the beginning of the end. But it is, perhaps, the end of the beginning." -Winston Churchill

To kick off every week for nearly a year now, we've begun it with Messier Monday, where we take an in-depth look at the 110 deep-sky objects that make up the first elaborate catalogue of fixed night-sky wonders that could possibly be confused for transient comets. Originally, when first published, this catalogue was made up of 103 objects; the final 7 were added posthumously. Each one tells its own unique story, yet all of them tell a sliver of our own story, and give us a window into our place in the cosmos.

Image credit: Rich Richins, of all 110 Messier objects (in no particular order), from a 2009 marathon.

Today, let's take a look at the very last object in the original catalogue as it was published by Messier: the rich star cluster in Cassiopeia, Messier 103. After sunset (or, really, at any time) tonight, look towards the north from anywhere above the Earth's equator.

Image credit: me, using the free software Stellarium, via http://stellarium.org/.

Polaris -- the bright star located almost exactly at the north celestial pole -- is visible at all times (with clear skies and horizons) from all locations in the northern hemisphere. The entire sky appears to rotate around this point, and it's flanked on opposite sides by two prominent configurations of familiar stars: the Big Dipper, shown off-screen to the left (except for the tip of the "cup", Dubhe), and Cassiopeia, the "W" to the right of Polaris in the image above. To locate Messier 103, look to the bottom of the first "V" in the "W" at the bright star Ruchbah.

Image credit: me, using the free software Stellarium, via http://stellarium.org/.

Even on a night with a bright Moon (like tonight), even a pair of binoculars is revealing enough that if you look at Ruchbah, and head over just one degree towards the first star in the "W" of Cassiopeia (ε Cas), you can't miss M103, just slightly "below" the imaginary line that connects the two.

Image credit: me, using the free software Stellarium, via http://stellarium.org/.

This is one of the smallest open clusters in Messier's famed catalogue, just a tenth-of-a-degree (or 6') in diameter. Yet, located in the plane of the Milky Way (albeit far away from the galactic center), Messier 103 is a remarkable object for teaching us about the young clusters where the galaxy's newest stars reside.

Silhouetted against the dense star field of the galactic disk, there's one star -- a bright, blue triple star -- that clearly outshines all the others when you look towards this young cluster. Surprisingly, this star is definitively not a member of M103, but rather a foreground star known as Struve 131, a blue supergiant just a few hundred light-years away. But Messier 103 is located some 8,500-9,200 light-years away, making it (probably) the most distant open star cluster in the entire Messier catalogue!

Image credit: Lynn Easley, taken just last night, at http://www.astrobin.com/full/56654/?mod=none.

If we focus on the colors of the stars in this cluster -- ignoring the blue supergiant at the lower left, above -- you'll see a large number of bright, blue stars, and one bright red one in the center. It's the colors of these stars, more than any other property, that teach us the most about the cluster itself.

Newborn stars come in a wide variety of colors, brightnesses and masses: the most massive ones are the brightest and bluest, while the less massive ones shine less brightly and give off lower-energy, redder light. But the most massive ones also burn through their fuel the fastest, and when they run out of hydrogen fuel in their core, they expand into red giants, burning heavier elements until they run out of those, too, and die in planetary nebulae or -- if they're massive enough -- supernovae!

The brightest hydrogen-burning stars in M103 are still very young, blue and massive, but the red one in the center is, in fact, a red giant that left the main sequence only a few million years ago, at most.

Image credit: Hillary Mathis, N.A. Sharp / NOAO / AURA / NSF.

The abundance of intrinsically bright, blue stars, as well as the absence of the brightest class of blue stars -- the O-stars -- allow us to place the age of this cluster at a mere 22-25 million years, or just around 30% the age of the Pleiades.

There are at least 172 member stars in this cluster, although -- based on what we know of open clusters -- there may be as many as 1,000 stars or more in there. An interesting take on this cluster comes from 2MASS (the two-micron all-sky survey), which looks in the far infrared portion of the spectrum, preferentially highlighting redder stars and muting the intrinsically brighter, bluer stars.

Image credit: Two Micron All Sky Survey (2MASS) / UMass / IPAC / Caltech / NASA.

The best true-color "amateur" image I could find of this was taken by Jim Misti, although, given the fact that he used a 32" (0.8-meter) telescope, amateur is a loose term.

Image credit: Misti Mountain Observatory / http://www.mistisoftware.com/.

Beyond that, there is a Hubble space telescope image. Although my image processing skills leave a lot to be desired, I did want to point out that there are more than 1,200 identifiable (albeit, many may be spurious) sources here, and I've done my best to clean up the Hubble image so you can scroll through just a tiny portion of this cluster, although dead pixels still remain. It may not look impressive, but remember just what a tiny portion of the cluster the Hubble space telescope actually images; you're seeing faint stars as points-of-light that aren't even visible in any other image presented here!

Image credit: NASA, ESA, the Hubble Legacy Archive and me.

For those of you who want to see something better than that (and I don't blame you), here's a high-resolution look through the core of Messier 103 thanks to Jim Misti, which reveals just how rich this cluster -- as well as the outskirts of the galactic plane -- happen to actually be!

Image credit: Misti Mountain Observatory / http://www.mistisoftware.com/.

And that will do it for another Messier Monday! Including today’s entry, we’ve taken a look at the following Messier objects:

M1, The Crab Nebula: October 22, 2012
M2, Messier’s First Globular Cluster: June 17, 2013
M5, A Hyper-Smooth Globular Cluster: May 20, 2013
M7, The Most Southerly Messier Object: July 8, 2013
M8, The Lagoon Nebula: November 5, 2012
M11, The Wild Duck Cluster: September 9, 2013
M12, The Top-Heavy Gumball Globular: August 26, 2013
M13, The Great Globular Cluster in Hercules: December 31, 2012
M15, An Ancient Globular Cluster: November 12, 2012
M18, A Well-Hidden, Young Star Cluster: August 5, 2013
M20, The Youngest Star-Forming Region, The Trifid Nebula: May 6, 2013
M21, A Baby Open Cluster in the Galactic Plane: June 24, 2013
M25, A Dusty Open Cluster for Everyone: April 8, 2013
M29, A Young Open Cluster in the Summer Triangle: June 3, 2013
M30, A Straggling Globular Cluster: November 26, 2012
M31, Andromeda, the Object that Opened Up the Universe: September 2, 2013
M33, The Triangulum Galaxy: February 25, 2013
M37, A Rich Open Star Cluster: December 3, 2012
M38, A Real-Life Pi-in-the-Sky Cluster: April 29, 2013
M40, Messier’s Greatest Mistake: April 1, 2013
M41, The Dog Star’s Secret Neighbor: January 7, 2013
M44, The Beehive Cluster / Praesepe: December 24, 2012
M45, The Pleiades: October 29, 2012
M48, A Lost-and-Found Star Cluster: February 11, 2013
M51, The Whirlpool Galaxy: April 15th, 2013
M52, A Star Cluster on the Bubble: March 4, 2013
M53, The Most Northern Galactic Globular: February 18, 2013
M56, The Methuselah of Messier Objects: August 12, 2013
M57, The Ring Nebula: July 1, 2013
M60, The Gateway Galaxy to Virgo: February 4, 2013
M65, The First Messier Supernova of 2013: March 25, 2013
M67, Messier’s Oldest Open Cluster: January 14, 2013
M71, A Very Unusual Globular Cluster: July 15, 2013
M72, A Diffuse, Distant Globular at the End-of-the-Marathon: March 18, 2013
M74, The Phantom Galaxy at the Beginning-of-the-Marathon: March 11, 2013
M78, A Reflection Nebula: December 10, 2012
M81, Bode’s Galaxy: November 19, 2012
M82, The Cigar Galaxy: May 13, 2013
M83, The Southern Pinwheel Galaxy, January 21, 2013
M86, The Most Blueshifted Messier Object, June 10, 2013
M92, The Second Greatest Globular in Hercules, April 22, 2013
M94, A double-ringed mystery galaxy, August 19, 2013
M97, The Owl Nebula, January 28, 2013
M99, The Great Pinwheel of Virgo, July 29, 2013
M102, A Great Galactic Controversy: December 17, 2012
M103, The Last 'Original' Object: September 16, 2013
M104, The Sombrero Galaxy: May 27, 2013
M108, A Galactic Sliver in the Big Dipper: July 22, 2013

Come back next week for yet another one, as we won't stop until we've covered them all!

esiegel Mon, 09/16/2013 - 12:02

Tags

Gotta catch 'em all!

See, that's the problem with open clusters. They're too open. If they were more globby, the Hubble picture would be great.

Or they need to at least have some nebulosity. A few scattered stars can look amazing if surrounded by whispy clouds.

Can someone point me at M103's suggestion box? I have some more ideas on how it could improve its image.

How to find your very own supernova

esiegel — Fri, 24 May 2013 14:50:27 +0000

How to find your very own supernova

"Do you see the absurdity of what I am? I can't even express these things properly because I have to - I have to conceptualize complex ideas in this stupid limiting spoken language! But I know I want to reach out with something other than these prehensile paws! And feel the wind of a supernova flowing over me!" -Ronald Moore

Well, you probably don't actually want to feel the wind of a supernova flowing over you; trust me on this.

Image credit: ESO / L. Calçada, of the remnant of SN 1987a.

But to find one for yourself, that's definitely within your reach, if you know where to look.

Supernovae come in a few distinct types, two of which are far more common than others.

Image credit: STSCI, NASA; NASA/T. Strohmayer (GSFC)/D. Berry (Chandra).

There are Type Ia supernovae, the most common type of supernova in our own galaxy. These occur when a white dwarf star -- either from mass siphoning, accretion, or mergers -- reaches above a certain mass threshold. When this occurs, the atoms at the center of the stellar corpse can no longer remain stable, and a runaway nuclear explosion occurs. The result -- as we've seen relatively recently in our galaxy -- is a fantastic supernova explosion that destroys the previously existing star!

Image credit: NASA/ESA/JHU/R.Sankrit & W.Blair.

But these types of supernovae -- the Type Ia -- can occur anywhere where white dwarf stars are located. Given that these are the second most common stellar-type object (behind red dwarf stars) in the Universe, at least for the next few hundred billion years (after which they'll eventually overtake red dwarfs), predicting where the next one will occur is a herculean task, well beyond what we know how to do.

But there is another type.

Image credit: Anglo-Australian Observatory, via Pete Challis.

When ultra-massive stars, or stars at least about eight times as massive as the Sun, exhaust the last of their nuclear fuel, the core of that star begins to collapse. Normally -- and this happens in stars like the Sun -- the forces between particles in the central region of the star are too strong for even gravity to overcome. This is true for nearly all classes of main-sequence star; our Sun is a run-of-the-mill G-class star.

Image credit: wikimedia commons user LucasVB.

But some stars are so massive -- all of the main-sequence O-stars and the brightest of the B-stars -- that the Pauli Exclusion Principle is insufficient to prevent core collapse, and this leads to a runaway reaction.

In the center of these stars, the core does in fact collapse, producing either a neutron star or black hole at the center, while the outer layers of the star are destroyed in a fantastic Type II supernova explosion!

The thing is, stars like this are very, very rare; less than 0.1% of all stars are massive enough for this to happen. Furthermore, stars that are this massive live for such short amounts of time before burning through all of their fuel.

But this is great, because it tells us something: if you want to find one of these Type II supernovae, you're way more likely to get one if you look at a young, star-forming region of space!

Image credit: NASA,ESA, M. Robberto (STScI/ESA), HST Orion Treasury Project Team.

We have a few of these star forming regions in our own galaxy, of course, perhaps the most famous of which is the Great Orion Nebula, prominently visible during the winter months.

But you don't mine for gold in a tiny vein when there are giant ones to go after, and you don't look for supernovae in HII-regions of relatively quiet galaxies when there are places in space so active that the entire galaxy in question is a star-forming region!

Image credit: NASA / JPL-Caltech / STScI / CXC / UofA / ESA / AURA / JHU.

The easiest way to get a galaxy that forms stars this rapidly is when two relatively equal-sized galaxies merge. The gravitational interaction causes large amounts of the gas in both progenitor galaxies to contract down and form new stars. When this happens, the star formation rate can become tens, hundreds or (possibly) even thousands of times as great as it is in our own Milky Way.

While the vast majority of stars (99.9%+) created will be too low in mass to go supernovae, you don't really care about that when you're creating millions (or hundreds of millions) of stars. Eventually, one of them is going to blow.

Image credit: flickr user yu244720, a.k.a. (Robert) Sean Davies.

If you hear about it, and you know where to look, you can, of course, see it for yourself.

But if you're really lucky, you can be the one looking at the right time to discover it! In fact, amateur astronomer supernova hunters can, individually, discover dozens of new supernovae on their own. The best place to look? You guessed it: merging and interacting galaxies!

Image credit: NASA, ESA, the Hubble Heritage Team and A. Evans.

These are the cosmic hotbeds of star formation, and hence they're also the most prolific cosmic supernova factories. But looking at any one galaxy in particular, just once, isn't going to tell you very much. (Even if it's one of the most active galaxies in the entire known Universe.)

Image credit: NASA/ESA/Hubble Heritage (STScI/AURA)-ESA/Hubble Collaboration.

That's because what you need to do is find a galaxy and compare it to earlier images of that same galaxy. It's only when you get an unexpected brightening -- a rapid, extreme brightening -- that rises and falls over the span of many days, that you've got a candidate for a supernova.

And if you find one, that only means you've got a candidate supernova. For confirmation, you need spectroscopic follow-up, and that almost always requires the attention of a professional.

Image credit: NASA / JPL-Caltech / STScI-ESA / S. Bush, et al. (Harvard-Smithsonian CfA).

This Hubble/Spitzer composite image shows the mammoth galaxy NGC 6240, an ultraluminous galaxy in the process of a major merger. Recently, astronomy outreach expert Adam Block took this spectacular wide-field image of this galaxy. The sight is spectacular, and (like for all images here) you can click for a full-resolution image in all its majesty.

Image credit: Adam Block/Mount Lemmon SkyCenter/University of Arizona.

Even though this galaxy is certainly undergoing higher-than-average rates of star-formation, it certainly isn't obvious that anything out-of-the-ordinary has happened here.

But something's worth checking out. Let's take a look at the highest-resolution Hubble image available of this galaxy, and in particular, I want you to focus on the star-forming region I've outlined in orange, below.

Image credit: NASA, ESA, the Hubble Heritage (STScI/AURA)-ESA/Hubble Collaboration, and A. Evans (University of Virginia, Charlottesville/NRAO/Stony Brook University).

This region is one of the hotbeds of star-formation. I mean, the whole galaxy is, but the blue reflection nebula tells you that there are some extraordinary hot, blue stars in there, as well as some neutral gas/dust, which reflects the light from those hot, blue stars.

The thing is, that image is from years ago. Let me take you inside Adam Block's image, now, and see if you can find anything interesting.

Image credit: Adam Block/Mount Lemmon SkyCenter/University of Arizona.

Look hard, detectives. Let me help you out, with a little zooming, cropping, and a couple of arrows.

Image credit: Adam Block/Mount Lemmon SkyCenter/University of Arizona (bottom), NASA / ESA / Hubble Heritage Team / A. Evans (top).

That has got to be a supernova! It's almost definitely a Type II, based on where it's happening, and even though it's probably a rather uninteresting one now that it's almost certainly on the decline (I believe the image dates from April 11th), if you happen to be a professional out there just twiddling your thumbs with clear skies and no targets of interest, take a spectrum of this and give Adam Block, who's created some of the most spectacular astroimages I've ever seen, his first supernova discovery!

Image credit: Adam Block/Mount Lemmon SkyCenter/University of Arizona.

And if you happen to be looking -- with the right equipment, in the right place, at the right time -- you, too, could find one of these for yourself!

esiegel Fri, 05/24/2013 - 10:50

Tags

Ethan,

This subject is near and dear to my heart, since I performed a supernova search as part of my dissertation. Let me warn prospective searchers that this is not a job for the faint of heart or short of patience. I observed once every two weeks for about two years, concentrating on galaxies with enhanced star formation rates, and found only 3 SNe in a sample of about 150 galaxies .... and in each case, someone else found it first. Sigh.

By the way, Type Ia are _not_ the most common supernovae in the Milky Way, based on all the evidence. The Milky Way is an Sb or Sc spiral, and surveys of other galaxies (for example,

http://arxiv.org/abs/1006.4613

show clearly that core-collapse supernova occur 2-4 times more frequently than SNe Ia in spirals of this sort.

Michael,

Ah, the bias of basing a conclusion like that on what we've seen for the past few thousand years! That is a very cool study; thanks for sharing!

So Type II supernovae are far less common in Milky Way type galaxies than they are in starburst (or other accelerated SFR) galaxies, but that still outpaces the Type Ias. Interesting!

Probably the greater amount of dust in spiral type galaxies explains that difference. More dust to collapse, bigger stars, more likely they're the size that goes boom because they fall in to themselves.

I *love* hindvision..!

Messier Monday: A Lost-and-Found Star Cluster, M48

esiegel — Mon, 11 Feb 2013 17:03:11 +0000

Messier Monday: A Lost-and-Found Star Cluster, M48

"Always try to keep a patch of sky above your life." -Marcel Proust

Welcome to another Messier Monday, where each week we take an in-depth look at one of the 110 deep sky objects that make up the Messier Catalogue! Messier was not the first person to try and make an accurate, large catalog of deep sky objects, but he was the first to successfully do so: most of his objects both actually exist, are deep sky objects, and had their positions recorded correctly.

Most, that is, but not all. Today, we'll be looking at the open star cluster Messier 48, one of the objects that does exist, is an interesting deep sky object, but that he incorrectly recorded the position of. Here on Earth, we describe a position by longitude and latitude; in astronomy, their counterparts are right ascension and declination. And while Messier successfully recorded the right ascension, his declination was off by five degrees.

Here's how you can find it for yourself.

Image credit: Me, using Stellarium.

Shortly after sunset tonight, you'll be able to find Orion high in the sky, with Sirius and Procyon trailing behind towards the east. A little farther away, to the left of the box above, is what appears to be the naked-eye star 30-Monocerotis (also known as C Hydrae), in the tail of the unicorn. But if you look closer, you'll find it's actually three stars in a line, close together. And if you take Messier's 1771 description of this object:

Cluster of very small [faint] stars, without nebulosity; this cluster is at a short distance from the three stars that form the beginning of the Unicorn's tail.

You can't miss it, even through a pair of binoculars or -- on a very clear, dark night -- with your naked eye.

Image credit: me, using the free software Stellarium, http://stellarium.org/.

There's a collection of stars clustered tightly together: that's Messier 48. This cluster was independently rediscovered 12 years later by Caroline Herschel, and has been well-known ever since, although Messier 48 has never acquired a nickname. But it provides us with an important example of a still young, but aging, star cluster.

Image credit: John Mirtle of http://www.astrofoto.ca/john/, from way back in 1992.

When stars first form in a region of space, they typically contain anywhere from a few hundred to a few thousand new stars, and they appear roughly evenly distributed (by mass) across the seven major spectral types.

Image credit: Morgan-Keenan spectral classification, by wikipedia user Kieff.

The O-stars burn through their fuel the fastest, dying the most quickly. After that, the bright B-stars run out of fuel, and that's the end of stars that will die in a type II supernova. Over time, the biggest, brightest stars continue to burn out, becoming red giants and dying in planetary nebulae.

Messier 48's brightest main-sequence star is of spectral class A2, which means this cluster is about 300 million years old. As you can tell by looking at it, it's already burned all of its nebulous dust off.

Image credit: Neil Fleming of http://www.flemingastrophotography.com/m48.html.

What you might not be able to tell -- not from the images I've shown you so far -- is the great diversity of color in this star cluster. As you'd expect, the brightest, most massive, bluest stars dominate the light coming from this cluster that's located about 1500 light years away.

Image credit: unknown, retrieved from http://www.mc2quantum.com/messier-objects-2/.

There are at least 50 stars visible through a very good pair of binoculars on a moonless night, and at least 80 stars (and probably many hundreds more, if you include the ones too dim to be seen at this distance) are visible through a better telescope. But what might not be obvious here is that there are quite a number of big, bright red stars as well.

Image credit: Siegfried Kohlert, via http://www.astroimages.de/en/gallery/M48.html.

Red giants (and three yellow giants) are stars that were just slightly more massive than the bright blue ones still shining, and these have entered a later, helium-burning phase of their life cycle. Someday soon (astronomically speaking), these stars will blow off their outermost layers in a planetary nebula, while the inner core contracts down to a white dwarf.

All the remaining stars visible at this distance will eventually do this, but only the bright red ones are getting close.

Image credit: Courtney Seligman, of http://cseligman.com/.

The brightest one (here at lower-left) might be getting quite close, but don't hold your breath: the processes that create a planetary nebula are not catastrophic, and take upwards of hundreds of thousands of years to complete.

If you take an image of this cluster that's both wide-field (considerably over a degree, or the equivalent of 22 light-years across at this distance) and deep, you'll find that there are some 165 identifiable stars in this cluster.

Image credit: Fred Espenak of http://www.astropixels.com/.

Unfortunately, none of NASA's great observatories or giant telescopes have imaged this relatively close-to-home deep sky object. But I was able to track down a fantastic image of the core of this cluster, courtesy of the Sloan Digital Sky Survey.

Image credit: SDSS.

The reds and blues here are so striking up against one another, I was tempted to call this the election map cluster! But I'm not the arbiter of names; so plain old Messier 48 it is. Messier wasn't perfect, but his catalogue is the first very good one of our sky, and continues to be both useful and gloriously gorgeous to this very day!

Including today’s entry, we’ve taken a look at the following Messier objects:

M1, The Crab Nebula: October 22, 2012
M8, The Lagoon Nebula: November 5, 2012
M13, The Great Globular Cluster in Hercules: December 31, 2012
M15, An Ancient Globular Cluster: November 12, 2012
M30, A Straggling Globular Cluster: November 26, 2012
M37, A Rich Open Star Cluster: December 3, 2012
M41, The Dog Star’s Secret Neighbor: January 7, 2013
M44, The Beehive Cluster / Praesepe: December 24, 2012
M45, The Pleiades: October 29, 2012
M48, A Lost-and-Found Star Cluster: February 11, 2013
M60, The Gateway Galaxy to Virgo: February 4, 2013
M67, Messier’s Oldest Open Cluster: January 14, 2013
M78, A Reflection Nebula: December 10, 2012
M81, Bode’s Galaxy: November 19, 2012
M83, The Southern Pinwheel Galaxy, January 21, 2013
M97, The Owl Nebula, January 28, 2013
M102, A Great Galactic Controversy: December 17, 2012

Come back next week for another Messier Monday, where we’ll look deep into the night sky, and admire the wonders that fill our galaxy, and beyond! With seventeen down, we've got plenty more to go; let me know which one you'd like to see featured next!

esiegel Mon, 02/11/2013 - 12:03

Tags

I have to admit that as a backyard astronomer I was not into open clusters. Your descriptions of some of the science behind the images has certainly made them more interesting. It might be nice to see the Messier open clusters arranged by age from young to old....

Nice.
The SDSS photograph is spectacular.
It forced me to reread the post, to understand the difference between the red and blue stars. Yes, I'm a slow learner; but if I hear the same thing enough times I'll remember.

I guess I never realized that open clusters have a relatively short life span.

"Estimated cluster half lives, after which half the original cluster members will have been lost, range from 150–800 million years." wikipedia

But what I can't find, maybe because it is so obvious, is what happens to the stars of an open cluster after the stars have become "gravitationally unbound"?

I assume that the stars then just become part of a nearby globular clusters or galaxy. Is this generally what happens?

And then my next question. Do most stars form in open clusters? I mean I know they form in gas clouds. And I know that spiral arms of galaxies are good breeding grounds. But I don't know if the gas clouds are mostly in the spiral arms and if then the open clusters of young stars mostly form there.

Any clarification will be appreciated.

"what happens to the stars of an open cluster after the stars have become “gravitationally unbound”?"

The stop being in an open cluster. They remain in the spiral arm, but are no longer a cluster of gravitationally bound stars but all single or multiple star systems like ours (or Proxima Centauri, or Sirius, or...).

"Do most stars form in open clusters?"

Pretty much. Any single gas cloud will be big enough to create thousands of stars.

The arms of a spiral are phantoms, caused by there being a rarifaction (between spiral arms) and compaction (leading the spiral arms) of gas in the disc and the stars are born (and are brightest on average) where the gas is dense enough to form star systems when perturbed, and only the dimmer ones survive long enough to remain burning when the spiral arm has "passed", making the trailing edge on average dimmer than the leading edge.

"The arms of a spiral are phantoms"

Next on Ghost Hunters: Are there ghosts hiding... in space?!

But like many words, the word phantom had previous meaning and was suborned into use to mean something paranormal.

phantom (n.)
c.1300, fantum "illusion, unreality," from Old French fantosme (12c.), from Vulgar Latin *fantauma, from Latin phantasma "an apparition" (see phantasm). The ph- was restored in English late 16c. (see ph). Meaning "specter, spirit, ghost" is attested from late 14c.; that of "something having the form, but not the substance, of a real thing" is from 1707. As an adjective from early 15c.

phantasm (n.)
early 13c., fantesme, from Old French fantosme "a dream, illusion, fantasy; apparition, ghost, phantom" (12c.), and directly from Latin phantasma "an apparition, specter," from Greek phantasma "image, phantom, apparition; mere image, unreality," from phantazein "to make visible, display," from stem of phainein "to bring to light, make appear; come to light, be seen, appear; explain, expound, inform against; appear to be so," from PIE root *bha- (1) "to shine" (cf. Sanskrit bhati "shines, glitters," Old Irish ban "white, light, ray of light"). Spelling conformed to Latin from 16c. (see ph). A spelling variant of phantom, "differentiated, but so that the differences are elusive" [Fowler].

Sorry, the existence of a supernatural connotation of the word is enough for a Ghost Hunter like me. It's not like what is essentially a pun makes for flimsier reasoning than any of the rest of it.

Messier Monday: A Rich Open Star Cluster, M37

esiegel — Mon, 03 Dec 2012 18:12:56 +0000

Messier Monday: A Rich Open Star Cluster, M37

"Who is wise? He that learns from everyone.
Who is powerful? He that governs his passions.
Who is rich? He that is content.
Who is that? Nobody." -Benjamin Franklin

Welcome to Messier Monday, where each week we take a journey into one of the 110 objects in the Messier Catalogue of non-cometary deep-sky objects. Ranging from stellar remnants to star clusters to globular clusters to distant galaxies and more, the Messier objects tell a rich and varied story that you can share in yourself through even the simplest of astronomical instruments.

Image credit: Rich Richins, of all 110 Messier objects (in no particular order).

This week, I'd like to introduce you to a rich collection of stars that -- unless you know about it -- you've probably never even stopped to consider. At this time of year, the great winter constellation of Orion rises in the eastern skies shortly after sunset, dominating its section of the night sky.

Image credit: me, created with the night sky software, Stellarium.

Farther up in the sky, the very bright star Capella (upper left) and the red giant Aldebaran (next to Jupiter right now) outshine all the other stars around them. But near Capella -- brightest star in the constellation Auriga -- a remarkable deep-sky object can be found just outside the border of the bright irregular hexagon taking up the bulk of that section of the sky.

Image credit: Me, using the software Stellarium, from http://stellarium.org/.

While this isn't really visible without binoculars or a telescope, it stands out as an extremely dense region of stars relative to the galactic background surrounding it, despite being over 4,500 light years away!

Image credit: Fred Espenak of http://astropixels.com/.

Located in the opposite direction of the galactic center from our perspective, Messier 37 is the brightest open cluster in its part of the sky, and packs an estimated 2,000 stars in a region of space just 20 light years in diameter. And -- let's be honest -- compared to the last open star cluster we looked at, Messier 45 (the Pleiades), it might not appear as spectacular.

Image credit: Twin City Amateur Astronomers.

But -- in its own way -- it is just as spectacular. But the beauty of this cluster might not be apparent at a mere glance; one must take the time to learn just a little bit about it to appreciate it. While the Pleiades is brilliant, blue, and visible to the naked eye, Messier 37 is actually twice as massive as its better known sibling.

It's also ten times farther away and about five times as old, coming it at around half-a-billion years, which is old for a star cluster.

Image credit: Emil Ivanov of http://www.emilivanov.com/.

The brightest and most massive stars that existed in this cluster died a long time ago; there are no O-class stars and only the dimmest B-class stars (the B9's) are still alive today; these are the brightest and bluest stars visible in the image above. But there are a sizable number of bright red stars in there, something completely foreign to the Pleiades.

Know why?

Image credit: Sloan Digital Sky Survey.

It takes hundreds of millions of years for stars -- the most massive stars that won't die in a catastrophic supernova -- to reach their red giant phase. That is, to burn up all of their core's hydrogen and begin fusing helium instead. In stars that are too massive, helium fusion is a quick phase, and it doesn't take very long to go from hydrogen fusion to a supernova.

But in stars below that mass threshold, the helium-burning phase itself can last tens-to-hundreds of millions of years itself, something that we're seeing right now in this dust-free, evolved star cluster!

Image credit: Robert Nanz of the San Diego Astronomy Association.

Unlike a supernova, these evolved stars will die by blowing off their outer layers in a planetary nebula, similar to the eventual fate of our Sun. Only, the stars in this cluster are still so young -- at half-a-billion years -- that even with all the right ingredients for life, it's possible that a world identical to Earth wouldn't have evolved its first living organism yet.

Messier 37 has never been viewed with a great space telescope like Hubble, but what's truly amazing is that dedicated amateurs, like all images (except the SDSS) above, can get just as good a view as the pros can, as the Canada-France-Hawaii telescope team's image, below, demonstrates!

Image credit: Harvey Richer, P. Durrell, G. Fahlman, J. Kalirai, F. D'Antona & G. Marconi.

In another few hundred million years, this star cluster will likely break up due to gravitational interactions, spreading the individual star systems throughout the galaxy, and filling it with yet another generation of rich new worlds, and another set of lottery tickets towards evolving intelligent, spacefaring life.

So, including today’s entry, we’ve covered seven of the 110 Messier objects so far:

M1, The Crab Nebula: October 22, 2012
M8, The Lagoon Nebula: November 5, 2012
M15, An Ancient Globular Cluster: November 12, 2012
M30, A Straggling Globular Cluster: November 26, 2012
M37, A Rich Open Star Cluster: December 3, 2012
M45, The Pleiades: October 29, 2012
M81, Bode’s Galaxy: November 19, 2012

Which one will be next? Join me next week for another Messier Monday, where we'll bring you the greatest sights and stories accessible to practically everyone with good skies and a little time, and let me know which object you can't wait to hear about!

esiegel Mon, 12/03/2012 - 13:12

Tags

Ethan, small typo. Capella is in the upper left, not right.

Thank you, DW!

Ethan Hello:
I was curious about the dark spots on M37 images, so I zoomed in (using photo software) on a few of the spots near the center of the photo's, and it seems like there is an occlusion of light from behind the spots, as if the spots are actually dark bodies (maybe smoke, or maybe extremely large rocky orbs) rather than just open space. Ref photo's above of Richer - Durrell, Twin City, and Ivanov.

At the end of their lives, stars glow hotter than ever!

esiegel — Thu, 11 Oct 2012 15:28:12 +0000

At the end of their lives, stars glow hotter than ever!

"A colour is a physical object as soon as we consider its dependence, for instance, upon its luminous source, upon other colours, upon temperatures, upon spaces, and so forth." -Ernst Mach

Our Sun, like all Sun-like stars, will come to the end of its life someday. All the hydrogen fuel in its core will eventually burn up, and when this happens, the core itself will begin to contract. When temperatures are finally high enough, the end product of hydrogen fusion -- Helium-4 -- will begin to fuse in the contracted core, and the Sun will expand into a Red Giant.

Image credit: Northwestern University's tutorial on Stellar Evolution.

The outer layers of (mostly) hydrogen will become very diffuse, and will eventually be blown off as the Sun goes through the next phases of its life, culminating in a planetary nebula.

Image credit: NASA and The Hubble Heritage Team (STScI/AURA); Acknowledgment: Dr. Raghvendra Sahai (JPL) and Dr. Arsen R. Hajian (USNO).

The core of the (former) star will eventually contract down to a degenerate white dwarf, while the planetary nebula will expand to be multiple light years in size, eventually cooling and dimming away over the timespan of many tens of thousands of years.

This is the fate of all Sun-like stars in the Universe, as far as we know, and the planetary nebulae that result are varied and beautiful, as many of them have been captured in rich, fascinating detail by the Hubble Space Telescope.

Images credit: NASA / STScI.

These images are all taken in different visible light filters, with different colors highlighting different elements in each image. But in addition to the type of light we're used to, theoretical work told us that it might be possible to create photons of much more energetic wavelengths -- X-rays -- than are normally possible in stars, during this phase of a star's life.

In theory, how is this possible?

Electromagnetic Spectrum Data. Image credit: NASA.

The gas surrounding the white dwarf can become so rarefied that the central, contracting star can super-heat the gas, shocking it, and causing the emission of diffuse X-rays near the central star. The surface of the star, as well, can become an X-ray emitting source, meaning that we can look for both a diffuse X-ray signal near the central region and a strong, X-ray point source at the location of the dying star itself.

And that's exactly what the Chandra X-ray Telescope did.

Image credit: Joel Kastner et al., 2012. From Astronomical Journal, 144, 58.

According to this recent paper, many of the nearest planetary nebulae to us were determined to exhibit exactly this. For the first time, point-source X-rays and diffuse X-rays could be separated out from one another.

In fact, the four planetary nebulae images by Hubble, three images up? They were found to all have diffuse X-ray emissions, and three of them were found to have central point sources, too! See for yourself what the X-ray data looks like.

Image credit: NASA/CXC/RIT/J.Kastner et al.

This is incredibly impressive! In fact, data was taken for 34 different planetary nebulae, to see which ones had this diffuse X-ray emission and which ones didn't.

The results are incredibly educational.

Image credit: Joel Kastner et al., 2012. From Astronomical Journal, 144, 58.

While many of these nebulae of all types had point sources (and many didn't), it's the smallest planetary nebulae, and preferentially the lowest temperature ones as well, that have diffuse X-rays! It's thought that the point sources may have something to do with whether these planetary nebulae originated from binary star systems or not, but what about the diffuse X-rays? They may be because they're the youngest planetary nebulae, still expanding and -- in many cases -- becoming less dense and moving farther away from the central, contracting stellar remnant.

But for these dying stars that have had the privilege of being imaged by both Hubble and Chandra, it means we now have the most enticing, educational and spectrally diverse images ever taken of a planetary nebula. And we have it for a whopping four of them!

Image credit: X-ray: NASA/CXC/RIT/J.Kastner et al.; Optical: NASA/STScI.

Don't laugh, that's four amazing pictures. You'll shut your mouth as soon as you click on each of the four individual images, below. There's the Cat's Eye Nebula, NGC 6543:

Image credit: X-ray: NASA/CXC/RIT/J.Kastner et al.; Optical: NASA/STScI.

The latter three don't have colloquial names, so I'm going to give them some. There's NGC 7662, the Fedora Nebula:

Image credit: X-ray: NASA/CXC/RIT/J.Kastner et al.; Optical: NASA/STScI.

There's NGC 7009, the Cheeseburger Nebula:

Image credit: X-ray: NASA/CXC/RIT/J.Kastner et al.; Optical: NASA/STScI.

And finally there's NGC 6826, the Brain Damage Nebula!

Image credit: X-ray: NASA/CXC/RIT/J.Kastner et al.; Optical: NASA/STScI.

Enjoy these new composite images, courtesy of Joel Kastner's international team and the Chandra X-ray Telescope, and keep in mind that this may give us a glimpse into our distant future: no discrete point source and a brief, diffuse X-ray glow in the early stages of our Sun becoming a planetary nebula!

(Thanks also to Peter Edmonds for bringing this story to my attention.)

esiegel Thu, 10/11/2012 - 11:28

Tags

I just got a bit confused with the following statement

"The gas surrounding the white dwarf can become so rarefied that the central, contracting star can super-heat the gas, shocking it, and causing the emission of diffuse X-rays near the central star. The surface of the star, as well, can become an X-ray emitting source, meaning that we can look for both a diffuse X-ray signal near the central region and a strong, X-ray point source at the location of the dying star itself."

When you mention the 'Surface of the Star' can emit X-rays so you mean it emits X-Rays when its a red giant?

VDGG, a rarified gas can only lose heat through radiation in the allowed transition bands and this is very slow compared to the black body radiation allowed by a hot dense gas.

Therefore the heat can build up because the contracting star is stull giving a LOT of energy out to the gas enveloping it but that gas can't get rid of it.

And red giants don't emit hot enough to manage to give out X rays. Wolf-rayet hot blue giants and stellar cores (the bit that you see as a white dwarf) are much much hotter (40,00K for a Wolf Rayet, 100,000K or more for a white dwarf), there is quite a lot of X-Ray radiation possible compared to the ~3,000K for a red giant.

Apropos of nothing:

http://www.guardian.co.uk/science/gallery/2012/oct/12/space-science-sta…

That quote from Ernst Mach didn't really add anything.

First of all it reeks of Ernst Mach's idealism – an color is certainly not an object.

And secondly if anything, a color has two components: The physical reality and subjective perception.

- The physical properties of the objects and processes involved in creating the spectral composition of the emitted/reflected/absorbed/etc. light, and the physical properties of whatever is used to detect the light, is the first component – this is the objective, physical, "materialistic", reality, if you so want.

- And the subjective human perception of light (through physical, "materialistic", yet subjective processes in human eye and nervous system, that have evolved to reach their present form) is the second component.

As much as I think that Ernst Mach contributed to science, as much I think that his idealism was one of the things that held him back.

What's funny in this context was his "believe only your senses" policy (to draw a cartoon version of it), which had an anti-idealistic core to it, yet led him to reject several scientific theories of the time, not the least Einstein's work – with Einstein in turn crediting Ernst Mach as a base for his work.

There might be other quotes by Ernst Mach useful today, but this is not it.

With a quick search I couldn't find much useful quotes. His quote "Science itself, therefore, may be regarded as a minimal problem, consisting of the completest possible presentment of facts with the least possible expenditure of thought." seems to be a (poor) paraphrase of Occam's razor. His quote "Personally, people know themselves very poorly." is nice, but a banal truism.

And "In reality, the law always contains less than the fact itself, because it does not reproduce the fact as a whole but only in that aspect of it which is important for us, the rest being intentionally or from necessity omitted." Yeah. Science produces with "laws" an abstraction and approximation of the "facts" of reality.

Ernst Mach, not a good source for one-liners.

And oh, lest I forget: Really great images!

I wish I could include more images into the "False Color" wikipedia article, but I fear I put to many in it already… But if you have better suited examples that the currently included Astronomy example (Messier 66), feel free to go to wikipedia and edit the False Color article, take out Messier 66 and put another one there!

Tony, despite all those words laid out, I have ABSOLUTELY NO IDEA what it was you wanted to impart there other than some unflattering comments on Ernst Mach.

On second thought, the Messier 66 image was created using four channels, so use an Astronomy image with four channels if you want to change something there!

NGC 6826, the Brain Damage Nebula! I love it. The Fedora Nebula is a perfect moniker. Cheeseburger is a bit of a stretch, but not really any more than the colloquial names of many other nebula and so I'm more than happy with it. Can we google-bomb these terms so they become the de-facto names? or are you not supposed to mention when you're trying to manipulate google?

Let's change the subject.

How will NuSTAR contribute to these observations?

I like "Jelly Bean Nebula" for the second one.

Very nice science. Excellent work.

And very nice explanation.
Let me let it sink in.
Then I need to reread it again from the beginning.
Thanks for the education.

And what a sense of humor these astronomers have:
- the Cat’s Eye Nebula
- the Fedora Nebula
- the Cheeseburger Nebula
- the Brain Damage Nebula
If you're up late at night doing looking at stars; you might as well have a crazy good time with a lot of crazy talk.

Where do Supermassive Black Holes Come From?

esiegel — Mon, 30 Jul 2012 19:55:17 +0000

Where do Supermassive Black Holes Come From?

"Black holes, which have no memory, are said to contain the earliest memories of the universe, and the most recent, too, while at the same time obliterating all memory by obliterating all its embodiments. Such paradoxes characterize these strange galactic monsters, for whom creation is destruction, death life, chaos order." -Robert Coover

Our Milky Way, the swath of light and dark that dominates the darkest skies here on Earth, contains a huge variety of stars: large and small, red and blue, from young to old to ancient.

Image credit: ESO / Serge Brunier, Frederic Tapissier, The World At Night.

But the very center of our galaxy contains, deep within its heart, one object that's unlike any other. Completely dark in the visible part of the light spectrum, due to the neutral gas and dust that prevent the light from getting through, we can successfully peer through to the center of the galaxy only in very specific wavelengths, and only from space.

When we do so, one region stands out from all the others, no matter how we look.

Images credit: NASA, ESA, SSC, CXC, and STScI; rectangles by me.

That bright region, outshining all the others in each wavelength? That's the innermost, supremely central region of the Milky Way. If we take our highest-resolution telescope, in the wavelengths most transparent to light, what do we find in this central region?

Image credit: Silas Laycock (CfA).

In short: a mess. Thousands upon thousands of stars crowded into a region of space that -- if it were of our local neighborhood instead -- would contain only our Sun.

Yet at one very small, special location, known as Sagittarius A*, an incredibly bright radio source lives among the young, hot, but otherwise relatively normal stars.

Image credit: ESO / R. Genzel et al. / Max-Planck-Institut fur Extraterrestrische Physik.

What's going on in that region marked by those two yellow arrows? The stars there are orbiting something with incredible speeds, something that, according to the known laws of gravity, is millions of times the mass of the Sun.

Image credit: KECK / UCLA Galactic Center Group / Andrea Ghez et al.

Oh, and also, it emits no light. That, my friends, is how we know we have a supermassive black hole at the center of our galaxy. It turns out that practically every galaxy has one, and the larger the galactic bulge, the larger the black hole at the center.

Composite image credit: X-ray - NASA, CXC, R.Kraft et al.; Radio - NSF, VLA, M.Hardcastle et al.; Optical - ESO, M.Rejkuba et al.

Most supermassive black holes are dormant -- or not active -- most of the time, and thus, like our own, are very difficult to detect. But looking deep into the Universe with the Chandra X-ray telescope, we were able to see a large number of active supermassive black holes.

Image credit: D. M. Alexander, F. E. Bauer, W. N. Brandt, et al., NASA and PSU.

When we extrapolate what we see here to the entire Universe, we find that about 300 million supermassive black holes are active and pointed at us at any given time.

That correlation of bulge-size to black hole mass is a good one, and there are only three known exceptions: one is when a merger kicks a black hole out of a galaxy, one is when a galaxy has some of its mass stripped away, as in the case of the galaxies below...

Image credit: X-ray: NASA/CXC/SAO/A.Bogdan et al; Infrared: 2MASS/UMass/IPAC-Caltech/NASA/NSF.

and perhaps most bizarrely, one is in the very early stages of the Universe, when the earliest supermassive black holes are more massive than you'd naïvely expect they would be. I was recently asked about this, and it is a very good question. So why do these supermassive black holes form, and why do they grow so massive so quickly?

After all, when we see supernovae, if they create a black hole at all, they only create a black hole that's a few times the mass of our Sun.

Image credit: R Jay Gabany of http://www.cosmotography.com/.

Maybe the largest supernovae we've ever seen created a black hole 20 or 30 times as massive as our Sun, but that hardly explains how we get up to millions or (in the largest cases) billions of solar-mass black holes.

To understand how this happens, I need to you imagine all the way back to the early stages of the Universe: before our Solar System existed, before large clusters of galaxies merged and formed, before generations of stars lived and died, before even the first clouds of gas and dust collapsed to form stars. Imagine back to when the Universe was relatively uniform, dark, and only beginning to have the most overdense regions begin to contract down, where they will eventually form the very first stars in the Universe.

Image credit: NASA / WMAP.

Eventually, the hydrogen and helium gases in the densest locations achieve high enough densities to ignite the first nuclear fusion reactions, causing stellar burning and star formation for the very first time. This is a Universe containing maybe 10²³ solar masses worth of hydrogen and helium, and the very first locations that are lucky to form stars will do it in chunks that range from many millions of solar masses down to may be as small as a few hundred thousand times the mass of our Sun.

Now, like all star-forming regions, there will be a huge variety of the types of stars that we form. Most of the stars will be long-lived, dim, low-mass stars, with progressively fewer of the heavier stars as we look to the more massive end of the spectrum.

But it is these most massive stars that are most interesting: the hottest, brightest, bluest and also shortest lived, these are the stars that will form heavy elements in their core (allowing for the eventual formation of planets), go supernova (enriching the Universe), and -- in certain cases -- collapse to form black holes.

Image credit: Nicolle Rager Fuller / NSF.

But it is the most extreme stars -- the ones that are over 130 times the mass of our Sun -- that are the most interesting as far as forming a supermassive black hole goes. Sure, less massive stars can form smaller black holes, but once you get above 130 masses, the interior of your star becomes so hot and energetic that the highest-energy radiation particles you create can form matter-antimatter pairs, which create an instability in the star that wind up blowing the entire thing into smithereens!

Image credit: NASA / CXC / M. Weiss.

Of course, this doesn't help you create a supermassive black hole at all, does it?

The thing is, this is only true for stars with masses above 130 solar masses and below 250 solar masses. If we get even more massive than that, we begin to create gamma rays that are so energetic that they cause photodisintegration, where these gamma rays cool down the interior of the star by blowing the heavy nuclei back apart into light (helium and hydrogen) elements.

In a star with more than 250 Solar Masses, it simply collapses entirely into a black hole. A 260 solar mass star would create a 260 solar mass black hole, a 1000 solar mass star would make a 1000 solar mass black hole, etc.

The question, of course, is do we actually make these, and do we make them in abundance that it's reasonable they would grow to form early supermassive black holes? To answer this, we turn to the largest star-forming region in our wimpy local group: the Tarantula Nebula located in the Large Magellanic Cloud.

Image credit: ESO / IDA / Danish 1.5 m / R. Gendler, C. C. Thöne, C. Féron, and J.-E. Ovaldsen.

This region of space is nearly 1000 light years across, with the massive star-forming region in the center -- R136 -- containing about 450,000 solar masses worth of new stars. This entire complex is active, forming new, massive stars.

It should be no surprise that our most recent, close supernova -- SN 1987a -- originated on the outskirts of the Tarantula nebula.

Image credit: the Hubble Heritage Team (AURA/STScI/NASA).

But it's not the outskirts, but the central, R136 region that is most spectacular. Let's dive right in to the hot, bright blue stars.

Image credit: NASA, ESA, & F. Paresce (INAF-IASF), R. O'Connell (U. Virginia), & the HST WFC3 Science Oversight Committee.

You may notice, right away, that there's one bright star that isn't blue at all, but rather red. This is an important star that may, in fact, become our night sky's next supernova.

Image credit: NASA, ESA, & F. Paresce, R. O'Connell, & the HST WFC3 S.O.C.

But this red giant, even if it forms a black hole, won't form a very massive one. Remember, we're on the lookout for stars with masses over 250 times the mass of our Sun.

The amazing thing is this: there is one in here!

Image credit: NASA, ESA, & F. Paresce, R. O'Connell, & the HST WFC3 S.O.C.

The most massive star known to humanity, R136a1, weighs in at 265 solar masses, and if its core gives out right now, it will collapse immediately to a black hole of 265 solar masses! This star, in particular, may not do that because of the heavy elements present, but in the early Universe, there are no heavy elements present, and so all stars above this mass threshold will simply get converted into black holes!

Because of how galaxies are thought to form in the early Universe -- by the rapid merger and accretion of collapsed, star-forming regions -- it's unthinkable that these early, large black holes wouldn't merge with one another and grow, forming increasingly larger and larger black holes at the centers of these objects: the Universe's first large galaxies.

Image credit: The National Astronomical Observatory of Japan.

If we can get just one 250 solar mass black hole for every 500,000 solar masses worth of stars, that means by time we get up to a Milky Way-sized galaxy, with maybe 2-400 billion solar masses worth of stars, we'd expect a central supermassive black hole of 100-200 million solar masses! This is exactly the type of growth we need to create the largest of the supermassive black holes we observe today, and we've got the evidence that the right type of stars form right in our own backyard.

So that's where the earliest supermassive black holes come from, and I hope you enjoyed your journey through time, space, stars and the elements: they brought you the Universe you get to have today!

esiegel Mon, 07/30/2012 - 15:55

Tags

In the picture with the three views (x-ray, near infrared, and infrared) there's another interesting region off on the left that's kind of box shaped. Any idea what that is? It's one of the few regions that also seems strong in all three.

Wow, I thought the supermassive black holes were just the first in the bunch, who got lucky to eat all neighbouring matter and grew to enourmous scales. I can't picture two black holes merging, what would it seems like?

That KECK-animated gif is too dodgy to be taken serious as proof for a Black Hole. Here is a video of how they found the spot:
http://www.youtube.com/watch?v=E-BM5_JyTeY

One picometer 'off-target' and 'our' view would have been blocked by some other star. Being able to capture this 'action' is almost the same chance as winning the lottery.

And the starts that seem to be twirling around that one spot, are just too vague to judge if they are in that specific area, and what their path is. This looks like a fraud ... emperor's new clothes.

The supermarket.

Easy.

The supermarket.

Easy.

The supermarket.

Easy.

Ethan - just let me thank you for doing such a GREAT job. Your content is comprehensive, accessible and sooo enlightening. I've been doing this astro thing for over 45 years and think myself relatively well informed (for an amateur), but you nearly always surprise me.

Hello Mr. Siegel! I have one question for you, if you don't mind. You said "Most supermassive black holes are dormant".... How can that be? How can a black hole not be active?

Thanks!
-Chelsea

Hmmm.

The site commenting system seems a little borken.

Post didn't appear. Tried under a fake ID to see if it were rate limiting, but that didn't appear either.

It looks like just this one.

That multipost wasn't me. The comment system is borked!

Chelsea- the difference between active & dormant is whether it's eating something or not. Our central black hole seems to have cleared the space immediately around it, so it's considered dormant. No ionized jets are visible. In other galaxies, we can see huge emissions from their cores, with spectacular jets shooting thousands of light years into space. I believe there were recent observations of one that indicated it had just eaten a whole star. Sorry I can't recall where it was, maybe Ethan knows?

Speaking of site problems, I push the Subscribe - RSS button at the top, but the reader says "no articles" and I never get any. It's been like that since the recent move. I'm running Safari over Lion on a MacBook Pro.

On topic, what might happen to these black holes as inflation accelerates? Will they rip apart?

@chelle: The "Keck animated video" Ethan posted is not an "artist's conception," and neither is some of the video you cited. They are both _real_data_!

The color coding indicates the signal intensity from the pixels of their CCD (the circles show you how much the point-like stars are smeared out when you look at them, which is called the "point spread function").

In your video, the boxed plot from 0:56 to 1:27 is exactly the same data, but shown in grey-scale rather than false color. Those are actual pictures of actual stars within ~3 lightyears of Sgr A*, not a cartoon.

We know that these stars are all orbiting a common point because we can _watch_ them, over the course of about a decade, and use that information to fit their orbital parameters. They are all following very nice Keplerian orbits around a central point, just like the planets, asteroids, and comets in our solar system.

Here are some links to papers with the actual research behind that very nice video you posted.

A good general review: http://arxiv.org/abs/1006.0064

The gas cloud G2, tidally disrupted and possibly on a capture orbit: http://arxiv.org/abs/1112.3264, http://arxiv.org/abs/1201.1414, http://arxiv.org/abs/1207.4215

The close-in star S2: http://arxiv.org/abs/0910.3069

You can find a lot of really good papers on different aspects of Sgr A*, including discussions of near future _direct_ observations of the central SMBH, by searching arXiv for "Sgr A" in quotes, http://arxiv.org/find/all/1/all:+EXACT+Sgr_A/0/1/0/all/0/1

Michael,

I'm not saying that this animated gif nor the video is an 'artist’s conception' they are real alright. I only question the claims of it being stars circulating da black hole in the center of our Milky Way. Like I said the chance of being able to look at precisely THIS area is about one in a million. Haven't you seen how the detection of this spot is a continuous zooming-in between thousands of other stars, ... just a tiny fraction to the side and we would be able to see it. Could we really be this lucky, is what I ask myself. Second the imagery is so vague that with some ingenious visual enhancements you can make it look as if they're all in that confinement of space, it makes me think of an illusion done by David Copperfield. And yes the papers are very nice, it is only that the visual proof doesn't look sufficient enough. Maybe I've been fooled too many times (once) in my life that I have become too skeptical about things that look too good to be true. If you like to take this as valid proof, than that you are entitled to do so, but I'm not very convinced. Also I'd like to see what is there to see in a section next to this one and compare, and if all around that particular spot there is nothing going on well than you might have convinced me, but not this early in the game.

One more thing, I also would like to compare it to an N-body simulation and the gravity interaction of a few stars closely packed together and given a group rotational velocity without a 'black hole' near it. It might produce the same type of stellar dance.

OMG, RSS has been fixed ALREADY! Thanks, whoever...

Dr. Siegel -- I wish to thank you for writing these wonderful explanations of the universe. You know how to hold my attention. Thank you, Robert Buckley

Well.that answered my question about the center of the galaxy.

Chelle, the mass of the object orbiting is given by the valocity of the stars orbiting. The size is given by the shape of the orbit.

The density resulting csnnot be reasonably be explained by stellar objects.

Additionally, the brightness of a suitable cluster central mass if stellar in origin (remember stephan's law) would be readily discernable.

Stars don't cut it.

Wow, I'm not going to argue about the fact if there is or isn't a Black-Hole in the center of our Milky Way or any other galaxy. We've already had a lot of debating regarding this point and I respect your opinion.

I'm only focusing here on the 'proof' of that KECK-gif and YouTube-video. Look at it again as of 0:55

I have cut that part out and transformed it into a .gif-file:
http://www.freeimagehosting.net/newuploads/kqjiu.gif (1.4 Mb)

Look how the timeline goes up from 2004 up to 2011, and back down to 2002. This creates the illusion that those stars are making some Kepler loops. Yes, they have put the years next to it, but along with some soothing music and some extra more impressive visuals, you are in a way misleading spectators and creating an illusion, covering up the weakness of the proof.

Maybe the YouTube material is very vague due to uploading, but transforming it into the 'precise' KECK-gif-animation that Ethan presents here on the blog, seems to be a too presumptuous leap to me. All this along with the one in a million chance of capturing it, leaves me with no other option than to conclude that it is probably a fraud.

Well why don't you go and simulate the N-body problem blah blah blah and answer your question?

@Chelle

what are saying man? You think that youtube video is a proof for black holes??? That's just a nicely presented summary of piles and piles of data and analasys bundled down to 1:50 mins or so...

You say that couple of images don't proove it. ANd they don't. But you're the only one who seems to think that's all there is to it. Did you even bother looking at the papers mr. Kelsey linked to you? My bet is you didn't. And you were even arogant enough to dismiss them with a slight of a hand. Saying: "And yes the papers are very nice, it is only that the visual proof doesn’t look sufficient enough."

Go and read those papers, and if you still disagree, put valid questions and doubts about the methodology with specific issues if you can, instead of bashing some ppl for making a cool animation based on data.

What the hell do you want anyways?

> "why don’t you go and simulate the N-body problem

http://en.wikipedia.org/wiki/N-body_problem

Sinisa,

Check this article:
http://www.nature.com/nature/journal/v455/n7209/full/nature07245.html

It clearly states that Sgr A* is located off-center from the suggested supermassive black hole that would be at the center of our galaxy. The 'proof' from KECK appears to be no good.

> "What the hell do you want anyways?"

I do like to be entertained when I go see a movie or a have a laugh with my friends, but when it comes to science I prefer the truth.

@Chelle

"It clearly states that Sgr A* is located off-center from the suggested supermassive black hole that would be at the center of our galaxy. The ‘proof’ from KECK appears to be no good."

mmmm... NO!

You either missread the paper that you linked just now, or you do not understand what they are saying.

Quote from the paper you linked: "...suggesting that the bulk of Sgr A* emission may not be centred on the black hole, but arises in the surrounding accretion flow."

Read it for what it is, and not what you want it to be.
They are saying that the majority of x-ray emissions seem to be coming from the accretion flow and not the center itself. Accretion flow of the BLACK HOLE.

"You either missread the paper that you linked just now, or you do not understand what they are saying."

It's a common problem for chelle.

"Read it for what it is, and not what you want it to be."

Hasn't happened yet.

chelle, why don’t you go and simulate the N-body problem?

you averred you have done it:

"I also would like to compare it to an N-body simulation and the gravity interaction of a few stars closely packed together and given a group rotational velocity without a ‘black hole’ near it. It might produce the same type of stellar dance"

SL, I think Chelle wants science to be wrong.

Just that.

"SL, I think Chelle wants science to be wrong."

Even more than that he wants himself to be right, with aliens, crop circles, worldwide scientific conspiracy, CERN destroying the universe, black hole fraud and the whole nine yards... Oh yes, and little quantum organisms swimming in eather.

Sinisa,

Here is the link to that paper itself:
http://arxiv.org/pdf/0809.2442v1.pdf

It says:

"A long-standing astronomical goal is to resolve structures in the innermost accretion flow surrounding Sgr A* where strong gravitational fields will distort the appearance of radiation emitted near the black hole ...
This is less than the expected apparent size of the event horizon of the presumed black hole, suggesting that the bulk of SgrA* emission may not be not centered on the black hole, but arises in the surrounding accretion flow."

And now let's look at that KECK-simulation that zooms straight in to where the radio source of the Black Hole is, and guess what, 'BINGO!' The Milky Way's Black-Hole is just right in front of our eyes with looping stars around it and even a 'flare', well the best thing is that we got it on tape. And gee, wow, that is a one in a million shot ... it must have been our lucky day! Well this is the stuff for 'true believers' like you and Wow, but not for me, sorry.

> "Oh yes, and little quantum organisms swimming in eather."

Ha ha, yes, I'm still busy with it, here's a little teaser:
http://youtu.be/CTqaiMpcOJg

p.s. Ethan I hope you don't mind this little off-topic plug, if Sinisa hadn't mentioned it ...

SL, I think that these "theories" of chelle are really just mechanisms to achieve the goal: "Science is wrong".

Wow,

That is a good observation. Indeed I'm trying tho prove that some theories of Science are wrong and that there are fraudulent illusions being used, and all this by using the Scientific method.

"Scientific method is a body of techniques for investigating phenomena, acquiring new knowledge, or correcting and integrating previous knowledge."
http://en.wikipedia.org/wiki/Scientific_method

"Indeed I’m trying tho prove that some theories of Science are wrong and that there are fraudulent illusions being used,"

ok, good luck with that. So basically you're saying Ethan and the rest of the community are frauds spreading disinformation.

So what in the world are you doing here?

Try integrating the knowledge that is new to you, rather than rejecting it all the time so that you can continue to peddle idiotic pseudoscience.

> "So what in the world are you doing here?"

First of all I'm here because Ethan's posts are presented in the most fun way, there is always a story to them, and they go straight to the heart. And it is not because I don't agree with all the material that he brings up, that I'm anti-science. Science is a far too broad field, to classify criticism about one subject as an attack on Science. In fact scientific research is about 99% failure and 1% success, and now I'm even being to optimistic, but that is the truth.

Second, I visit this place because I like to participate in the debate, but I also want to keep an honest view. And if I think that the LHC is a hazardous thing, than I will say so, even if it is the bread and butter for a lot of scientists who depend on it, physics is not sociology; and if I find this KECK-sim a fraud than I will also speak my mind; and I will also defend a possible NEW Aether because it is a super interesting concept with lots of possibilities. This is what science is about, sharing ideas and impressions, it is not only about listen & learn (integrating the knowledge that is new to you). Sinisa for a big part I see you doing the same thing; asking questions all the time, and sharing opinions. Perhaps I have an eye for some more global aspects, and not so much one for the more specified details that you are very good at. We all have different views, so it is imho best to keep an open mind.

Chelle,
Your point seems to be that its unexplainable or low-probability that we should be able to see this phenomenon. That it is suspiciosuly easy to do.

But Ethan's comments after the second picture describe just how difficult it is. We can only observe it using a few, specific, wavelenghts. Which are way outside the visible range. And which require space-based telescopes.

So I can't see what your issue is. Yes, there IS lots of stuff in the way. Yes, this stuff DOES block our view of it. Ethan says that very clearly - intervening gas and dust make it invisible in normal wavelengths. You are exactly right - it WOULD be suspicious if we had a clear visual shot of it. But you are wrong in implying that we have such a shot. We don't. Astronomers need exacting and unusual instruments to observe it precisely because we don't have a clear shot at it.

Its like arguing: isn't it suspicious how we can just see individual atoms with scanning tunneling microscopes? What are the odds that the instrument's capability exactly matches the size and properties of an atom? Answer: no, and 100%. Those instruments took a lot of time and effort to build, and they are designed precisely to overcome all the detection problems we have seeing individual atoms. There is nothing suspicious, easy, or suspiciously easy about it.

Eric,

> "it WOULD be suspicious if we had a clear visual shot of it."

Exactly, if you look at my first comment, the overall 3rd one in this thread, than you'll notice that I only question here the KECK-gif, that is intended to be 'a clear visual shot of it', and there is also this animation:
http://www.youtube.com/watch?v=E-BM5_JyTeY

You can argue about what a 'visual' shot is, as these 'images' are generated by captured radio-waves, but if I understand correctly, than those signals can also be simply blocked by a single star. Our Sun for example has a diameter of 1.4 million kilometers, so how could a radio telescope, even one that is a few kilometers wide, ever look at a very large area beyond one single star when it stands in its way, … and there are thousands of stars in that area that can 'visually' block the suggested Black-Hole in the center of our Milky Way. So yes with radio-waves we can look further through clouds of gas and dust, but not through other stars that block our vision. Anyway, to be able to capture what's going on at the exact spot of the grand BH of our Galaxy seems to me one hell of a lucky shot.

Excellent explanation Ethan!!

Chelle freely admits, "I’m anti-science... scientific research is about 99% failure and 1% success."

But even in this statement, Chelle misrepresents himself. He implies that he is only against the 99% of scientific research that ends in the dustbins of science history.

But Chelle is anti-science because he is against the 1% of science that is a success, i.e. that is supported by thousands (even millions) of observations.

wikipedia "Direct Doppler measures of water masers surrounding the nuclei of nearby galaxies have revealed a very fast Keplerian motion, only possible with a high concentration of matter in the center. Currently, the only known objects that can pack enough matter in such a small space are black holes."

My point is that 100s of failed explanations were tried; but the only 1 that worked, the successful explanation is that the "Milky Way galaxy has a supermassive black hole at its center, 26,000 light-years from the Solar System, in a region called Sagittarius A." This is an example of the less than 1% of scientific research explanations that is correct (i.e. is in agreement with the thousands and millions of observations and data).

Our Sun for example has a diameter of 1.4 million kilometers, so how could a radio telescope, even one that is a few kilometers wide, ever look at a very large area beyond one single star when it stands in its way

Because (1) no stellar objects "stand" in our way, they move fairly rapidly across our field. Because (2) you are thinking of the signal origin as a point source 'hidden' behind a sun, when in fact the signal source is much much bigger than any stellar object that would move between it and us. To be 'bigger' than the sourse, it would have to be much closer to us, but the density of stars drops precipitously outside of the core. And because (3) stellar objects do not simply block light, they bend it, acting in some ways like a lens.

Though I think in this particular case, (3) is largely irrelevant because of the distances, distributions of stars, and speeds involved. You are essentially wondering how a GPS signal can reach my transponder with all the potential gnats in the way.

"You are essentially wondering how a GPS signal can reach my transponder with all the potential gnats in the way."

Lol, I have no problem accepting that there is a strong signal in the middle of our Galaxy that we can receive, but what I do question is the KECK-gif and that YouTube video, that claim to show some gnat circulating around the signal source, behind all the gnat that's flying in-front of it.

btw regarding that strong signal, I wonder if it couldn't be something like the mechanism that causes Brownian motion, an accumulation of small signals that acts as one big punch, as the center is surrounded by a wall of stars and dust, a lot of signals could be bouncing around, just like a guitar body that works like an amplifier :)

Chelle, a galaxy is far larger than 14 million km across. Our sun isn't bigger than a galaxy.

Wow, fill a page with hunderds of dots. Now try to draw a straight line from the outside towards the exact center without passing one dot. Now increase the situation to 200 billion, because that is the amount of stars in our Milky Way, and try to do the same thing, because we are on the outskirts of the spiral Galaxy, and the strong radio signal is in the middle. Keep in mind that every dot has a diameter of about a million km. See how difficult it is to get a peek at what's going on right in the middle. Of course you can pick up the big signal, but to hit 'bulls eye' is a case of extreme luck, it isn't just one Star that you have avoid, but columns and columns of randomly distributed stars, it all adds up, line after line, increasing at each step the chance of getting your view blocked. And it is not like looking further into deep space that can widen out, here everything gets to be more compact the further you look. That's why I find those claims highly suspicious.

"fill a page with hunderds of dots. Now try to draw a straight line from the outside towards the exact center without passing one dot. Keep in mind that every dot has a diameter of about a million km"

Don't forget the relative scale of things. Compared to the interstellar distances, 10^6 km would be an essentially infinitesimal size. There is so much space between the dots that it would be difficult for one to actually get the way.

Chelle,

Remember, the universe is very very old and very very big so extremely unlikely events happen a lot more frequently than your able to wrap you human brain around. The universe doesnt care what you think should and shouldn't be. The piles and piles of data/observations lead us to the best possible explination. I don't get whats so hard to accept. You have been given several excellent reasons why stars and dust dont block the view. Whats the hang up?

The hang up is that, for chelle, the science cannot be right.

Ergo the explanations on how its right cannot be correct.

Close binary systems are hundreds of millions of km apart.

Or less than 1/100th the size of the star.

That are CLOSE BINARY separations.

The 4 light year separation between us and the nearest star is not unusual, however, which is 80000 times further.

Lol, I have no problem accepting that there is a strong signal in the middle of our Galaxy that we can receive, but what I do question is the KECK-gif and that YouTube video, that claim to show some gnat circulating around the signal source, behind all the gnat that’s flying in-front of it.

Your example shows why your intuition is wrong. We see gnats behind gnats all the time, because they don't move together. Relatively different movement makes it easy to subtract foreground objects to get the background.

And again, like Jasso in that I think your intuitions about object density are all wrong. As a more astronomically relevant metaphor, does the asteroid belt doesn't occlude our view of Jupiter? No.

[In fact, getting object densities in space wrong is a very typical sci-fi gaffe. Movies show ships having to dodge and weave to avoid getting hit. In real belts, the asteroids are so distantly spaced that you'd need a telescope to see one object from another.]

There's a lot of gas and dust in the way, but Real galactic densities are much lower than you

err... there's an extra "doesn't" in there and that last line should finish with "expect."

"The orbits of stars within the central 1.0 X 1.0 arcseconds of our Galaxy. In the background, the central portion of a diffraction-limited image taken in 2010 is displayed. While every star in this image has been seen to move over the past 15 years, estimates of orbital parameters are only possible for the seven stars that have had significant curvature detected. The annual average positions for these seven stars are plotted as colored dots, which have increasing color saturation with time. Also plotted are the best fitting simultaneous orbital solutions. These orbits provide the best evidence yet for a supermassive black hole, which has a mass of 4 million times the mass of the Sun. " http://www.astro.ucla.edu/~ghezgroup/gc/pictures/orbitsOverImage10.shtml

"Stellar orbits at the Galactic center proving the existence of a black hole. The star S0-2 dominates our knowledge about the central potential, since with an orbital period of 16 years it has been tracked throughout a whole orbit. The other stars have longer orbital periods and therefore only a fraction of their orbits is covered by observations... With care, the planned astrometric and spectroscopic adaptive optics observations for Ro, along with measurements of other short-period stars, should enable measurements of stellar orbits with sufﬁcient precision to detect non-Keplerian effects due to General Relativity (GR) and extended dark mass. The leading order effects are the special relativistic transverse Doppler shift and the gravitational redshift. These effects should be observable when S0-2 goes through its next closest approach in 2018 thereby marking a test of Einstein’s equivalence principle... A detection of GR effects in the orbital motions of the short-period stars at the Galactic enter would probe an unexplored regime of GR, which is the least tested of the four fundamental forces of nature" http://arxiv.org/pdf/1207.6755v1.pdf

So not only to we have 15+ years of orbital data. from which the composite images and videos sammarize. That astronomy research program aimed at the center of our Milky Way galaxy is precise enough that by 2018; it will have collected enough data to " test of Einstein’s equivalence principle" and "unexplored regime of General Relativity".

This is very nice, spectacularlly persistent, precise and excellent astronomy research of the highest calibre. Absolutely amazing.

Chelle chooses to NOT question the pretty good working hypothesis of how supermassive black holes are formed; in which there is room for discussion about various details of the excellent explanation that Ethan gives..

Chelle chooses to question the most precise astronomical measurements imaginable; he question observational research data that had been carefully, precisely gather for 2 decades and will continue in with even more precision and diligence for next decade.

Chelle chooses to argue against the most successful of the 1% of science successes; i.e. the most precise observations, verified by the best telescopes around the world and in space (Hubble) in an international research program that has spanned 20 years.

This is why Chelle is anti-science; because he attacks the very best science;
as he promotes psuedoscience analogies "Brownian motion.. one big punch... a guitar body that works like an amplifier"

And NEVER, does Chelle stop and refelect and say, "I did not know that. that is amazing science." Chelle learn something and bring something important/relevant to the science discussion.

OKThen,

Oh yeah, sure I am an Anti-scientist, no problemo :mrgreen:

Jasso, Wow, crd2 and Eric,

I have been talking about chance and until a certain point it is clear that we are lucky to peek straight into the heart of our Milky Way, and yes this is for al large part to due because of the scale of things. Nonetheless, there could have been some star in the way blocking our view. Anyway, for winning the lottery you need to have all the numbers correct, of lets say a ticket with 8 digits. Now let's compare this to our situation, and I agree that we have clearly all the first seven digits correct, because until a certain point we have a clear view at the heart of the Milky Way. Now comes the question do we also have the 8th and last number correct? It is here that I would like to take a look at the information that we have. I made an overview for ya'll:
http://m.UploadEdit.com/bat/1343919122764.jpg

As you can see in the first image (A) with all the 'Normal Stars' that Ethan originally posted here on the blog, you can see that we have a clear entrance towards 'the center'. The next question now is, what is the center and how do we now that it IS the center? Here it is the Complex Radio Source 'Sagittarius A' that shows us the way, that you can see in (B), and a close-up (C) with the location of the proposed Black Hole 'Sgr A*'.

To now look through all the clouds of dust we use the images from the Keck Observatory, made with the Observatory Adaptive Optics (AO) systems and its Laser Guide Star (LGS). It gives us the Central 4"x4" image (D), and it is full of Stars. And we can look more closely at 1"x1" (E) where we start noticing a lot of movement and 7 stars that follow the Kepler Ellipses (F). All the way at the right, we there's a 0.5" x0.5" image (G), that shows all the details.

What I find strange when looking at these pictures, is that our supposedly giant Black Hole Sgr A* is located in a dark bay-area 'off-shore' from where all the red-action is (C), but than again that dark bay is full of Stars (D), and they're all moving around just like we can see in the KECK-gif that is presented here. What I would like to know is if there are no other Kepler type of motions going in on in that large Bay-area, instead of only that particular spot, and what IS actually going on in the red-hot land section?

Next, let's have a look at picture (F); there we can see in the upper-left corner a very large bright object, perhaps one Star or a group of stars, but it is a rather significant body, very close to Sgr A*, and it makes me think that a lot of that Central Core of our Milky Way (Sagittarius A), might be full of that kind of objects that could be visually blocking parts of the core, as it would be the case when we would move a picometer ‘off-target’ in our first image (A), or in image (D)... there is even the question of how deep we have to zoom-in (???) because some Wikipedia says that: "The exact distance from the Sun to the Galactic Center is notoriously uncertain.

All this makes me question if we have indeed got our 8th and final number correct, and got to be very lucky; or if we got just very close and have picked something that looked as funky as a Black Hole, but that may in fact be some n-body celestial interaction of which there could be many more in the center of our Milky Way.

"and until a certain point it is clear that we are lucky to peek straight into the heart of our Milky Way"

You mean that certain point of actually thinking about whether it's a lucky happenstance or a pretty normal occurrence?

"Nonetheless, there could have been some star in the way blocking our view."

How likely is that?

> How likely is that?

True. You can indeed also pose the question; how lucky one could be to find a star in it's way, it works in both ways. I would say pretty lucky once you enter that central parsec, look at that 4"x4" it is still packed full with Stars, and that region isn't even in the zone where the strongest radio noise comes from.

Radio-wise it also seems to be rather problematic to tell what the actual center is, because beyond a certain point the center is just there, and finding that one particular Black Hole looks like finding a needle in a haystack. There doesn't seem to be a clear signal, what I would expect from a Super Black Hole that is roughly 100.000 solar masses, it mainly is that big radio cloud.

I hve posed the question. You, however are presuming an answer.

You don't get to 'say it both ways' because you are claiming incredulity based on a specific answer.

If you cannot show it unlikely to be clear of obstruction, you must withdraw the claim.

You know it's pointless arguing with someone who reverse-engineers their way from the answer to the evidence using analogies and unexamined gut feelings, right? They'll either eventually wake up and realize how logic and reasoning work (or at least consider it worth while to find out), or they'll continue to fill up the internet with drivel, spurred on by the attention.

But hey, I'm not telling anyone how to spend their time. If it's what amuses you that's cool. If not... successful troll is successful.

CB,

That's a true story.

Anyway It looks like I've found the missing link in the 'reverse-engineer' process:
http://www.astro.utu.fi/~cflynn/galdyn/GalCntr_lg.gif

This red-island fits, with some twisting and turning, into the bay-area of that 'Complex Radio Source' image, and has a clear dot it the middle, and looks like a bit the eye of a hurricane.

@eric
I loved your typo:
"Real galactic densities are much lower than you"
A rather good assessment of chelle's density.

I would expect from a Super Black Hole that is roughly 100.000 solar masses, it mainly is that big radio cloud.

On what do you base your expectation? Did you do a calculation that disagrees with published measurements?

Look, maybe its best that you just stop using metaphors and analogies altogether (to be fair, I will too), because they seem to be leading you to wrong conclusions. Just re-look at Ethan's 5th picture. The center is very crowded, yes, but it seems pretty clear that we can resolve individual objects in this region.

What is your alternative hypothesis for this? Do you think astronomers are doctoring their images? Do you think its not a black hole? Its gravitational and spectral properties don't seem to match anything else. What do you think image 5 is really showing, if not what Ethan says it is?

Eric,

My problem is that I'm skeptical about the existence of Black Holes as a singularity, because I personally guessed that as a singularity it would stick out more in space, due to the proposed Hawking Radiation, I find it also strange that one type would continuous suck up energy and such. Therefor I was skeptical about finding such a Black Hole, and I always thought of the origin of a Galaxy as something that is similar to the mechanics of a Hurricane; a matter of the Thermo Dynamics in the DM & DE / Aether and plasma and dust clouds, along with the forces of gravity, therefor I imagined that the core of a galaxy would be like the eye of a tornado, with lots of particles twirling and spinning around. So when I saw that animated gif I thought it would have been nothing else but a shot of one of the many the solar bodies that are vastly around moving in and around the center. Also the Black Hole / Galaxy Center seems have the 'weight' of the amount of stars that makes up a galaxy, in an n-body situation that might level out I suppose, and gravity would be the most intense in the core. For example in the case of a F4 tornado here on earth, there is an equivalent energy input of 100+ Tsar Bombs concentrated in such a vortex, while in the eye it is calm.
But now it looks in the images exactly like the eye of a hurricane in a giant storm, just a single dot in a closed off section that differs from the next area around it, spiraling out etc.

Seeing how those 7 stars rotate around that central point, still leaves the door open for a non-singular object also because the orbits don't seem to fit perfect. Although I can accept the physical correctness of a Galaxy with a super massive BH in the center. I'm just wondering of the current path of Science just checking if my intuition makes sense or not.

Nonetheless no one can't deny that is quite amazing to be able to see and capture the exact motion of those stars at in the center, we have been lucky.

"because I personally guessed that as a singularity it would stick out more in space, due to the proposed Hawking Radiation"

You will need to read up on what Hawking Radiation is first:

http://en.wikipedia.org/wiki/Hawking_radiation

cliff notes version: you're doing it wrong.

Forget the nonsense that certain folks CHOOSE to spout to deliberately obfuscate, misinform, etc.. all with purpose to discredit science. Of course such anti-scientist "are constantly at work to invent so-called alternative theories and craft legislation.. to require.. to teach unscientific notions." Daniel J. Fairbanks pg 7.

But such anti-science pugalists do science the great service of forcing scientist communicate science more clearly. e.g. Daniel J. Fairbanks excellent, astonishing new book Evolving (The Human Effect And Why It Matters) 2012 is science writing at its best. http://www.goodreads.com/book/show/14289169-evolving

Science today precisely deals with the seemingly seemingly impossible experiments and observations.

"Particle physics uses a standard of "5 sigma" for the declaration of a discovery. At five-sigma there is only one chance in nearly two million that the result is wrong, i.e. the measurement seen is a random fluctuation."

"In October 2006, the X Prize Foundation, working in collaboration with the J. Craig Venter Science Foundation, established the Archon X Prize for Genomics,[47] intending to award US$10 million to "the first Team that can build a device and use it to sequence 100 human genomes within 10 days or less, with an accuracy of no more than one error in every 1,000,000 bases sequenced, with sequences accurately covering at least 98% of the genome, and at a recurring cost of no more than US$1,000 per genome."... In June 2009, Illumina announced that they were launching their own Personal Full Genome Sequencing Service at a depth of 30× for US$48,000 per genome... Jay Flatley, Illumina's President and CEO, stated that "during the next five years, perhaps markedly sooner," the price point for full genome sequencing will fall from US$48,000 to under US$1,000... In May 2011, Illumina lowered its Full Genome Sequencing service to US$5,000 per human genome, or US$4,000 if ordering 50 or more."

From genomics to particle physics to astronomy; observations and experiments are being done with mind-boggling precision. And that incredible precision is the standard process of production in research, medicine and engineering.

"Six Sigma became well known after Jack Welch made it a central focus of his business strategy at General Electric in 1995, and today it is widely used in many sectors of industry... A six sigma process is one in which 99.99966% of the products manufactured are statistically expected to be free of defects (3.4 defects per million). Motorola set a goal of "six sigma" for all of its manufacturing operations, and this goal became a byword for the management and engineering practices used to achieve it."

Get use to it!

Chelle, your last post is so filled with bs that I can't help but reply. Over and over again you claim you're here to learn and preach scientific methods and what science is suppose to be, yet your last post obviously marks you as total opposite.

"I’m skeptical about the existence of Black Holes as a singularity,"
- lie... they needn't be singularities at all. Just need to have enough gravitational pull to not allow even EM radiation to escape. This very thing was a topic of one of Ethan's posts a while back. And you even read and commented on that post. So don't put singularities here as excuse.

"I personally guessed that as a singularity it would stick out more in space, due to the proposed Hawking Radiation"
- lie... with this sentence you clearly show you haven't got even a basic notion of what Hawking radiation is.

"Therefor I was skeptical about finding such a Black Hole"
-lie...after more than a year on this blog you haven't learned a single thing. Why is that is beyond me. Your notion of BH is non-existant since you lack the knowledge of even the fundamental notions of physics of BH's. "such" a black hole as you think of them are only in your head. Not science, but your haphazard daydreams.

"I always thought of the origin of a Galaxy as something that is similar to the mechanics of a Hurricane;"
- that's your problem and your own lack of knowledge. Not the problem of people here or physics in general. God knows you had plenty of opportunity to learn, you chose not to.

"a matter of the Thermo Dynamics in the DM & DE / Aether and plasma and dust clouds,"
- there is so much bs in this sentence that I won't even comment it. Perhpas this sentance is the best representation of your total persona. Let's mix and mash some fancy sounding words that might seem related to cutting age science and some kid might think I'm cool. Not a scientist but a total sharlatan and fraud.

"I imagined that the core of a galaxy would be like the eye of a tornado,"
- yes.. you imagined. Physics and this blog don't deal with unicorns, lepricons, hobbits, crop circles and imagined things. They deal with scientific concepts and experiments. You are the only one putting up fictional bs where it doesn't belong. I love sci-fi and epic fantasy, but I don't write about that here, nor do others.

"in an n-body situation that might level out I suppose"
- lie... you haven't got the faintest idea of what would happen, you just desperately want to sound like you know what you're talking about. You're not fooling anyone here.

"Seeing how those 7 stars rotate around that central point, still leaves the door open for a non-singular object"
- again bs. Seeing what? singularity or non singularity has nothing to do with rotation of stars. You've just shown all of us here you don't even know how gravity works.

"also because the orbits don’t seem to fit perfect"
-lie.. you would so wish to sound educated and important. Fit what? Perfect? What would the perfect orbit be?

"Although I can accept the physical correctness of a Galaxy with a super massive BH in the center"
-lie... you don't know enough physics to accept to decline anything dealing with cosmology. You've shown that in previous sentances

"I’m just wondering of the current path of Science"
- the sooner you leave it be, the better of Science will be. God forbid we ever get "scientist" like you.

"just checking if my intuition makes sense or not."
- it doesn't

"we have been lucky"
- guess what brainiac, luck has nothing to do with it. A lot of hard work by a great number of dedicated and professional people made all that possible. Without them we wouldn't see anything. This isn't lottery.

“I’m skeptical about the existence of Black Holes as a singularity,”
- lie… they needn’t be singularities at all. Just need to have enough gravitational pull to not allow even EM radiation to escape. This very thing was a topic of one of Ethan’s posts a while back. And you even read and commented on that post. So don’t put singularities here as excuse.

You might be right although it says on the wiki-page:

Since the central singularity is so far away from the horizon, a hypothetical astronaut traveling towards the black hole center would not experience significant tidal force until very deep into the black hole. - http://en.wikipedia.org/wiki/Supermassive_black_hole

And the singularity HAS NOTHING TO DO WITH HAWKING RADIATION YOU BLITHERING BUFFOON.

It isn't visible because its buried in the event horizon.

"the singularity ... It isn’t visible because its buried in the event horizon."

That's an interesting point. I would have thought that it was 'beyond' the event horizon. Arrr, bring me that horizon so I can check it out: http://youtu.be/CMZCK7dsmc0 (0:50)

What do you think the difference is?

> "What do you think the difference is?"

In the case of something like a hurricane, the wall that makes up the eye in the middle, would also be the event horizon, and this ring-wall would indeed be where the massive object is.

If it would be something like a single massive object, like a star, than the event horizon would surround that object and thus the 'singularity' would beyond it.

The difference is, that the former is the result of a 'whole' lot of action and energy going around making up that event horizon wall, while the latter is considered to be an object by itself, a singularity.

Can't see how te hurricane analogises. Where's this singularity analogy?

"Can’t see how te hurricane analogises. Where’s this singularity analogy?"

Exactly.

Exactly none?

OK. There wasn't a point, then.

And you didn't answer what the difference was, did you. Just went off on one of your signature idiot tangents.

Ethan,

Really great article, a fast and easy read, fantastic photos, especially the animation and the Tarantula nebula shots, well done. I look forward to many more.

Thank You,
Mike

Wow,

I did answer your question, my point was, that there is no point that causes the attraction in the case of a hurricane, versus the singularity that is a massive object. It is a group mechanism versus an individual object (Black Hole). Just like how pulling the plug in you bath creates a whirlpool, there is only an opening, not an object, and a lot of pressure of the whole of the water in your bath, the speed of the stuff that gets to be swung around, is the cause of a global mechanism, not that of a singularity.

There is a REPULSION in a hurricane centre. Gravity, the operating force in a black hole is ATTRACTIVE.

Therefore the two are not analogous.

Despite that, you did not answer the question which was what is the difference between buried inside an beyond the event horizon.

PS do you know anything about how a hurricane (or indeed any low depression cyclonic storm)?

..forms.

(Oopsie, clicked send too early)

There is a REPULSION in a hurricane centre. Gravity, the operating force in a black hole is ATTRACTIVE.

Here is an image showing what's going on:

http://tinyurl.com/hurricane-mechanics

There is NO repulsion in the hurricane center, and like I've now said plenty of times, the hurricane has no massive point in the center (singularity), so there is nothing beyond or inside the event horizon. The wall that makes up the eye of the hurricane, is the event horizon, that is the difference.

Read up on centrifugal forces, kid.

The geostrophic equation gas a term for that in there which puts a limit on the depth of a depression.

The centrifugal force has got nothing to do with, do you never take a bath, If so than you would notice that the drag of the whirlpool of the water, energy flowing out, sucking everything along with it there is no repulsion. What do you think the DM & DE Fluid is doing there, just hanging tight?

Regarding the 'geostrophic equation' look at that radio image of the center of the Milky Way and compare it to this temperature image of an hurricane's eye:

http://www.nasa.gov/centers/goddard/images/content/135564main_goes_ir_l…

It was this radio image that I was referring to:
http://www.astro.utu.fi/~cflynn/galdyn/GalCntr_lg.gif

"The centrifugal force has got nothing to do with, do you never take a bath"

You missed out a middle to that sentence.

And the bath plughole would need to be fifty miles across for cyclonic flow to cause the spinning we see in synoptic systems (which is what you're alluding to, because you are getting Coriolis forces mixed up with centrifugal ones).

You are as clueless about the hurricanes you so obsess over and see everywhere as you are about just about everything else.

"Regarding the ‘geostrophic equation’ look at that radio image of the center of the Milky Way"

Bugger me.

You really are even more clueless than I believed possible in a mobile human being.

Several problems here, all in a single tiny package.

1) There is no friction, pressure or lamelar flow in a galaxy, therefore you cannot apply the geostrophic equations.

2) If you look at the water going down a plughole, you'll see rotation just like the low pressure systems, but caused by a different mechanism.

3) That picture also looks like a cowpat. However, nobody is pretending that the Great Green Arkleseizure is doing a jobbie on the universe here.

4) Look at the centre of a non-spiral-arm galaxy. E.g. M81. You're looking for a pattern you WANT to see. And, unsuprisingly, you're able to find the pattern. Your idiocy is in thinking that just because you can find a pattern you understand what's causing it.

"There is no friction, pressure or lamelar flow in a galaxy"

Are you braindead?

No. Just because you're an idiot and don't like it, doesn't mean that the answer to anyone correcting you is "are you braindead?".

Chelle
Here's the deal.
There is a difference in arguing to win your case regardless the absurdity of your case (i.e. like a defense lawyer); and using your best arguments to learn and understand (i.e. like a scientist).

You argue like a defense attorney not a scientist.

So for example, when Wow explains, "There is a REPULSION in a hurricane centre. Gravity, the operating force in a black hole is ATTRACTIVE." The appropriate learning response should be, "Oh, I did not know." By the way I did not know. What I do know is that when Wow explains the science; he explains it correctly.

The you Chelle say, "Here is an image showing what’s going on: http://tinyurl.com/hurricane-mechanics There is NO repulsion in the hurricane center"

But have you looked at the very image that you show us. Look at the arrows in your image moving upward (red arrows) and outward (blue arrows). That outward is the repulsion that Wow describes.

There is nothing scientifically wrong with saying, "Oh, I did not know." Of course a defense attorney wants to win his argument regardless of reasonableness. But a scientist will throw out his best idea when it conflicts with observation (i.e. the various velocities measurements of the speed and direction of wind from the eye of a hurricane outward.)

Now a defense attorney will argue with such meteorologic data; but a scientist would rather be wrong and learn.

thus I thank Wow for explaining hurricanes better; I really haven't thought about them much. But if we are going to have good gneral relativity sense about something like a black hole; then we need to have a good classical mechanical sense about something like a hurricane. And understand how they are different, very different phenomenon.

So we each get to decide if we will be or not be scientifically minded. Being lawyerly minded regarding scientific things is to be a psuedoscientific, or anti-scientific.

Well, correctly enough for words.

To be correctly correct, you need the maths.

But the results of the maths can be REALLY weird. E.g. evanescent waves. Or the Lamb Shift. Heck, even the proof of why cyclones go anticlockwise in the northern hemisphere is kind of weird without the maths (or three pairs of double-jointed hands...).

A Hurricane is caused by the divergence of upper air wind. This causes the lower pressure in the centre (since there's less air there, there's less mass in the air column, therefore lower pressure).

The surrounding air is pulled in by the pressure gradient, along the isobaric pressure lines.

This causes rotation on a synoptic scale in accordance with the coriolis force.

However, the air is going IN and therefore describing a smaller and smaller circle around the low pressure zone, which means that it is turning a tighter and tighter circle. Which means the centrifugal force counters the pressure force inward.

These two forces balance out and you get a maximum pressure drop for a low pressure system and in the more extreme case of a hurricane, a calm area where the air cannot manage to get in because the incoming air is forced out by the centrifuge effect.

And therefore the air spirals up, the centre of the storm is somewhat self-sustaining and as long as enough energy is coming in to keep it going, the hurricane will survive a long time.

Upper air divergence occurs when something like the jet stream turns north, where the momentum change causes the air to slow. So we get a lot of temperate zone low pressure zones

See

https://www4.uwsp.edu/geo/faculty/ritter/geog101/textbook/weather_syste…

for a picture.

@OKThen,

"There is NO repulsion in the hurricane center”

But have you looked at the very image that you show us. Look at the arrows in your image moving upward (red arrows) and outward (blue arrows). That outward is the repulsion that Wow describes."

Come on, you can do better than that. Of course there is stuff flying out of the center, but not in the middle (centrifugal force) and that was what Wow was talking about.

Anyway here is an image of Gamma Ray jet's flying out and the bubbles that are formed: http://tinyurl.com/GAMMA-RAY-BUBBLES

p.s. if you find my style of discussing pseudoscientific anti-scientism than so be it, I don't care, what are you going to do, burn the witch?!

@Wow,

Yes that's a nice synopsis, and I agree with the fact that; "you need the maths". But something like a hurricane is a very complex organically evolving structure, you can calculate the forces but the whole mechanics of it is an interplay of many different factors. Similarly the mechanics of a Spiral Galaxy is something very complex and there is the questions of what the Dark Matter is doing towards the center, does it gradually changes 'temperature', are there flows, does the density changes, like you explain about a hurricane's center "... it is turning a tighter and tighter circle", what about such a more compact area of DM that interacts gravity-wise ... look how much empty space there is between those stars and how much more matter there could be compressed like foam, you could be talking about perhaps 10^x times more matter per cube, and you quickly come to the conclusion that a Black Hole (singularity) is the easiest answer ... and If you say that it is, than I will respect your opinion because mathematically it might work, but maybe in reality a Supermassive BH is more something of a process than an actual object.

The center of a hurricane is an eye; the center of a black hole is a singularity.

Hurricanes, bathtubs and toilet bowls do not have event horizons; despite Chelle's private definition "The wall that makes up the eye of the hurricane, is the event horizon."

We try to educate witches; and point out that witch people (e.g. like Chelle) generally add confusion to scientific discussion by parading private psuedoscience definitions, e.g. "center of hurricanes" and "event horizons of hurricanes".

What do you think pressure is, if not repulsion, chelle?

Are you here to get beaten up? Is that how you get your kicks? Because you're not even pretending to think any more.

OKThen & Wow,

I made my point, if you don't like than so be it.

Have fun!

What was the point?

You're clueless? Unloved? A troll?

Yes, I am a clueless unloved troll. :mrgreen:

Have fun!

I see the comments have turned from discussing the data and the models to personal attacks.
I’ll add my bit.
The Ghez papers discuss the data and suggests there are over a million suns size mass within 40 AU (use to be 60 AU) of the focus of the stars she tracked. What is the distribution of this mass? There were calculations (Richstone I think) that suggested that if Newtonian mechanics with gravity applied, then countering the self gravity would require a rotation velocity great enough to fling all the mass out. (I see the hurricane analogy but the mass is much greater than the analogy could allow.) Since this has not happened, the conclusion is there is some other force unmodeled by standard physics at work OR the mass would self gravitate to a supermassive black hole. There is some data that suggest it is not a supermassive black hole such as the periodic X-ray bursts (radiation in the X-ray band without accompanying radiation in other bands) and the apparent quiet nature of the mass (call a sleeping black hole in some papers). Here we have the problem.
I’m sure the scientists who would like to be funded wish the inconsistencies would just go away.
Certainly, all science models are wrong as if that is any news. Of course, current models will be replaced. Current models do explain considerable amount of data. Like General Relativity corresponded to Newtonian mechanics in limited circumstances, so the new model (currently called the “Theory of Everything”) should build on current models.