Astronomy
esiegel | May 5, 2012"Without a wish, without a will,
I stood upon that silent hill
And stared into the sky until
My eyes were blind with stars and still
I stared into the sky." -Ralph Hodgson
The next month -- from May 5th to June 5th -- brings three of the most spectacular astronomy sights possible on Earth back-to-back-to-back for skywatchers of all types, without telescopes, binoculars, or any special equipment. Tonight, May 5th, marks what's come to be known as a Supermoon, or the largest, brightest full Moon of the year.
Image credit: Chris Kotsiopoulos at Earth Science Picture of the Day.
Not that you'll…
esiegel | May 2, 2012"This is the way I wanna die. Torn apart by angry fans who want me to play a different song." -Regina Spektor
You're familiar with the classic picture of a black hole: a dark, dense region at the center from which no light can escape, surrounded by an accretion disk of matter that constantly feeds it, shooting off relativistic jets in either direction.
Image credit: University of Warwick, retrieved from bordermail.com.au.
This is a pretty accurate picture of active black holes. But most black holes aren't active, and of the ones that are, they aren't active most of the time!
Most people…
esiegel | May 1, 2012"A journey is a person in itself; no two are alike. And all plans, safeguards, policing, and coercion are fruitless. We find that after years of struggle that we do not take a trip; a trip takes us." -John Steinbeck
Here on Earth, we all get to enjoy the delight of being located in an extremely fortuitous place in our Solar System. Not just today, mind you, but billions of years ago, when the Solar System's planets were first forming!
Image credit: NASA / JPL-Caltech, retrieved from Jodrell Bank CfA.
Located close enough to our Sun, when the Earth first formed, like our neighbors Mercury,…
esiegel | April 28, 2012"They will see us waving from such great heights
'Come down now,' they'll say.
But everything looks perfect from far away
'Come down now,' but we'll stay." -The Postal Service
Whether you're under urban, city skies, where only a few dozen stars are visible on a clear night, or beneath some of the darkest skies on Earth, the Universe is out there, and you can get started discovering it, right now, for yourself. You can have yourself, as Bishop Allen would sing,
Another Wasted Night,or you can take advantage of it. For me, I currently live in Portland, OR, where the twilight looks like this.…
esiegel | April 25, 2012"Through that last dark cloud is a dying star... And when it explodes, it will be reborn. You will bloom... and I will live." -The Fountain
I want to start off by letting you all know that I, myself, do not have any children of my own. I have taught children, adolescents and adults for nearly a full generation now in varying capacities, and while each learner is different, there's one science fact that universally seems to shatter each and every one of them.
Image credit: the bloggers at Dear Kugluktuk.
The fact that the Sun, our Sun, the bringer of warmth, light, energy, and the sustaining…
esiegel | April 23, 2012"Some painters transform the Sun into a yellow spot, others transform a yellow spot into the Sun." -Pablo Picasso
But the Sun will not always be a bright spot. Though it has shone for billions of years already, and will continue to shine for billions of years more, it's currently doing this by burning its hydrogen fuel -- through the fires of nuclear fusion -- into the heavier element of helium.
Image credit: retrieved from UFO et Science.
But after about 10-12 billion years total, all the hydrogen that can be burned in the core will be used up! (There will still be hydrogen in the outer…
esiegel | April 22, 2012"Our planet is a lonely speck in the great enveloping cosmic dark. In our obscurity - in all this vastness - there is no hint that help will come from elsewhere to save us from ourselves. It is up to us." -Carl Sagan
Here on our planet, this is the one day that we take out of the year to stop and appreciate just how amazing the natural world really is, and how fortunate we are to have the Earth that we have. A wonderful but sad reminder of how fragile it is, and how quickly and easily we can affect it, comes through John Prine's great song,
Paradise.Here on our planet, there are countless…
esiegel | April 20, 2012"April is the cruellest month, breeding
Lilacs out of the dead land, mixing
Memory and desire, stirring
Dull roots with spring rain." -T. S. Eliot
Of course you all know the refrain, "April showers bring May flowers," but there's one April shower that brings fireballs instead: the Lyrids!
Image credit: John Chumack, retrieved from Bob King.
Like all meteor showers, the Lyrids come from a comet's dust trail that forms a great ellipse with respect to our Solar System. Once per year, the Earth, in its orbit around the Sun, passes through this dusty debris. When this happens, the Earth, moving…
esiegel | April 19, 2012"Science progresses best when observations force us to alter our preconceptions." -Vera Rubin
I want you to think about the Universe. The whole thing; about everything that physically exists, both visible and invisible, about the laws of nature that they obey, and about your place in it.
It's a daunting, terrifying, and simultaneously beautiful and wondrous thing, isn't it?
Image credit: NASA, ESA, S. Beckwith (STScI) and the HUDF Team.
After all, we spend our entire lives on one rocky world, that's just one of many planets orbiting our Sun, which is just one star among hundreds of billions…
esiegel | April 16, 2012"Truth is mighty and will prevail. There is nothing wrong with this, except that it ain't so." -Mark Twain
"It doesn't matter how beautiful your theory is, it doesn't matter how smart you are. If it doesn't agree with experiment, it's wrong." -Richard Feynman
Every day that you set forth in the world is a new opportunity to learn something about it. Every new observation that you make, every new test you perform, every novel encounter or piece of information you pick up is a new chance to be a scientist.
How so?
Image credit: Alan Chen.
You have a conception of how things work in this world…
esiegel | April 13, 2012"If we knew what it was we were doing, it would not be called research, would it?" -Albert Einstein
Our galaxy is but one among hundreds of billions in the cosmos, nearly all of which contain supermassive black holes at the center. Ours happens to be "only" a few million times as massive as our Sun, as well as quiet.
Image credit: ESO, R. Genzel et al. at MPI fur Extraterrestrische Physik.
In other words, our galaxy's supermassive black hole is behaving right now, by not viciously shooting off high-energy jets of particles and light at some poor, innocent passers-by.
But other galaxies are…
esiegel | April 11, 2012"We were left with a picture of part of the sky with no stars or galaxies, but it still had this infrared glow with giant blobs that we think could be the glow from the very first stars." -John Mather
When you look out at the night sky, you're limited by the light pollution from your surroundings, the imperfections of our atmosphere, the light-blocking gas and dust throughout the interstellar and intergalactic medium, and the capabilities of your eyes. Still, what one can see is truly a sight to behold.
Image credit: IronRodArt - Royce Blair of NightScapePhotos.com.
What if you didn't have…
esiegel | April 9, 2012"You cannot, in human experience, rush into the light. You have to go through the twilight into the broadening day before the noon comes and the full sun is upon the landscape." -Woodrow Wilson
Without a doubt, one of the most spectacular light shows of the cosmos happens when stars burn out -- reaching the end of their normal life cycle -- and die in a great supernova explosion. We've spoken in the past about the main ways that these stars die. Either a very massive star -- something more than ten times as massive as our Sun -- reaches the end of its nuclear fuel, and its core collapses,…
esiegel | April 7, 2012"Well you run and you run to catch up with the Sun but it's sinking,
racing around to come up behind you again.
The Sun is the same in a relative way but you're older,
shorter of breath and one day closer to death." -Pink Floyd
For the last four-and-a-half billion years, the Earth has spun on its axis, orbiting its parent star: our Sun. Today, our home planet looks something like this.
Image credit: Reto Stöckli, Nazmi El Saleous, and Marit Jentoft-Nilsen, NASA GSFC.
Looking at our world, even from outer space, you see some very familiar features that we think of as essential parts of our…
esiegel | March 30, 2012"A galaxy is composed of gas and dust and stars - billions upon billions of stars."
-Carl Sagan
Perhaps the most striking feature of the night sky under truly dark conditions isn't the canopy of those thousands of points of light, but rather the expanse of the Milky Way, streaking across the entire night sky.
Image credit: Richard Payne, retrieved from astro.wisc.edu.
With an estimated 200-400 billion stars contained within our island Universe, the Milky Way is just a regular, run-of-the-mill spiral galaxy compared to the rest of what's out there.
But it's our home. And, despite the…
esiegel | March 21, 2012"Deep into that darkness peering,
long I stood there, wondering, fearing,
doubting, dreaming dreams no mortal
ever dared to dream before." -Edgar Allen Poe
When you look out into the darkness of a moonless, unpolluted night sky, you'll of course notice that it's full of stars, planets, and the occasional extended object.
Image credit: Bob King at AstroBob.
But you'll also notice that there are plenty of regions that -- other than a few stars -- don't really have very much going on. One such region, visible in the southern skies pretty much year-round, is the constellation of Sextans.…
esiegel | March 20, 2012"When I had satisfied myself that no star of that kind had ever shone before, I was led into such perplexity by the unbelievability of the thing that I began to doubt the faith of my own eyes." -Tycho Brahe
When stars reach the end of their lives, there are many possible fates that they can have. Among the most spectacular, however, are stars that end their lives by going supernova, where a single star can outshine even an entire galaxy for a brief moment in time.
Image credit: SN 2006gy, X-ray by NASA / CXC, Nathan Smith, Weidong Li et al., IR by PAIRITEL / Lick / U.C. Berkeley / J.Bloom,…
esiegel | March 19, 2012"To use Newton's words, our efforts up till this moment have but turned over a pebble or shell here and there on the beach, with only a forlorn hope that under one of them was the gem we were seeking. Now we have the sieve, the minds, the hands, the time, and, particularly, the dedication to find those gems--no matter in which favorite hiding place the children of distant worlds have placed them."
-Frank Drake and Dava Sobel
Looking up at the canopy of stars in the night sky, and realizing that each point of light is a star system not so unlike our own, one can't help but wonder about those…
esiegel | March 14, 2012"Now go on, boy, and pay attention. Because if you do, someday, you may achieve something that we Simpsons have dreamed about for generations: you may outsmart someone!" -Homer Simpson
Today, March 14th, is known tongue-in-cheek as Pi Day here in the United States, as 3.14 (we write the month first) are the first three well-known digits to the famed number, π. As you know, it's the ratio of a perfect circle's circumference to its diameter.
Image credit: LeJyBy at Flickr Creative Commons, retrieved from sciencebuzz.org.
It's also very, very, very hard to calculate exactly, because it's…
esiegel | March 11, 2012"They call it a great wonder
That the Sun would not
though the sky was cloudless
Shine warm upon the men." -Sighvald, Icelandic poet
A couple of times a year, during the New Moon, the Sun, Moon, and Earth all line up in the same plane. As seen from Earth, the Sun's disc appears blocked, either in whole or in part, by the Moon. As The Beta Band would have told you, this creates an
Eclipse.Depending on how close the Moon and Sun are to the Earth, either the Moon's shadow will fall on the Earth, creating a total solar eclipse, or the shadow will end before it ever reaches Earth, in which case we…