Galaxies
esiegel | December 28, 2012"People hear the happy story, but the truth is they could all disappear in the blink of an eye. The threats just keep coming." -Todd Steiner
It's taken generations of scientists, examining the night sky for millennia, to comprehend the full size and scope of what's out there in the Universe.
Image of the southern Milky Way, by A. Fujii.
Out beyond the planets and stars, outside of the Milky Way itself, is a great cosmic abyss filled with still-uncounted galaxies that stretch for billions of light years across the Universe.
Image credit: 2P2 Team, WFI, MPG/ESO 2.2-m Telescope, La Silla, ESO…
esiegel | December 26, 2012"We have been forced to admit for the first time in history not only the possibility of the fact of the growth and decay of the elements of matter. With radium and with uranium we do not see anything but the decay. And yet, somewhere, somehow, it is almost certain that these elements must be continuously forming. They are probably being put together now in the laboratory of the stars." -Robert Millikan
The Universe has been around for a long time, but without the Big Bang, we'd never have any of the matter or starlight that gives rise to practically all of our experiences in the entire…
esiegel | December 17, 2012“Men... have had the vanity to pretend that the world creation was made for them, whilst in reality the whole creation does not suspect their existence.” -Camille Flammarion
Welcome to the latest -- and most controversial -- Messier Monday, where each week, I'll take a look at one of the 110 deep-sky objects that make up the Messier catalogue. These objects were identified so as not to be confused with potential comets, and make up the brightest and best-known observational sights beyond our own Solar System. But there is one object that, if you go to the wikipedia list, that has not been…
esiegel | December 6, 2012"Forget it. I didn't have that thing inside me where I wanted to smash against somebody and watch them break. I was too sensitive for that and disliked being that sensitive." -Josh Brolin
How do you figure out what something is made of? You take it apart -- cracking it open if necessary -- and look inside. This is something we've been doing since... well, since before our ancestors were even human.
Images credit: Elisabetta Visalberghi.
For most things here on Earth, that's easy enough. If you wanted to go down to the smallest scales possible, however, it becomes harder and harder to "crack…
esiegel | November 21, 2012“We live in an atmosphere of shame. We are ashamed of everything that is real about us; ashamed of ourselves, of our relatives, of our incomes, of our accents, of our opinions, of our experience, just as we are ashamed of our naked skins.” -George Bernard Shaw
All that is real about ourselves is nothing to be ashamed about; quite to the contrary, it's something to be eminently thankful for. This very existence is all we have, and while it's minuscule compared to the entire Universe, it required the entire Universe to bring us to the point where it's possible for us to exist.
What do I mean by…
esiegel | November 19, 2012"When you look at the stars and the galaxy, you feel that you are not just from any particular piece of land, but from the solar system." -Kalpana Chawla
Welcome to this week's Messier Monday, where I pick a new object out of the original catalogue of 110 "faint fuzzies" designed to help comet-hunters avoid confusion with these fixed, extended night sky objects.
Image credit: The Messier Objects by Alistair Symon, from 2005-2009.
In previous weeks, we've focused on a variety of objects, including a globular cluster, an open star cluster, a supernova remnant and an active star-forming nebula…
esiegel | November 7, 2012"It's a brilliant surface in that sunlight." - Neil Armstrong
Indeed, all that glitters so brilliantly in the cosmos does so because of the stars that have formed throughout it.
Image credit: NASA, ESA, and the Hubble SM4 ERO Team.
Over the 14 billion-or-so years that our Universe has been around, we've formed hundreds of billions of stars in our galaxy alone.
Image credit: ESO / Serge Brunier (TWAN), Frederic Tapissier.
Given that our galaxy is just one of at least hundreds of billions in the observable Universe, the number of stars that have formed over our Universe's history is a…
esiegel | October 5, 2012"It took less than an hour to make the atoms, a few hundred million years to make the stars and planets, but five billion years to make man!" -George Gamow
Earlier today, a video (from last month) was released where one of the members of the US House of Representative -- a member who sits on the House Committee for Science, Space and Technology -- proudly proclaimed the following:
"All that stuff I was taught about evolution, embryology, the big bang theory; all of that is lies straight from the pit of hell." -Paul Broun
Well, if the Big Bang is a lie from the pit of hell, then the Universe…
esiegel | September 28, 2012"It is by going down into the abyss that we recover the treasures of life. Where you stumble, there lies your treasure." -Joseph Campbell
One of the bravest things that was ever done with the Hubble Space Telescope was to find a patch of sky with absolutely nothing in it -- no bright stars, no nebulae, and no known galaxies -- and observe it. Not just for a few minutes, or an hour, or even for a day. But orbit-after-orbit, for a huge amount of time, staring off into the nothingness of empty space, recording image after image of pure darkness.
What would we find, out beyond the limits of what…
esiegel | September 10, 2012"Not even light can escape such hollowing, this huge mass in a small space. Even the Milky Way with its open arms is said to have a black hole at its heart." -Susan B.A. Somers-Willett
Our Milky Way is home to us all. With its hundreds of billions of stars, massive spiral arms, dust lanes, and orbiting globular clusters, it's no wonder that nearly everything we see in the night sky is contained within it.
Image credit: All rights reserved by Flickr user Greg Booher.
I say nearly everything, of course, because there are a few exceptions. The Andromeda Galaxy, for one, as well as the two…
esiegel | August 27, 2012"You must learn to talk clearly. The jargon of scientific terminology which rolls off your tongues is mental garbage." -Martin H. Fischer
I've always thought that the Universe is absolutely amazing; that everything from the tiniest indivisible particles all the way up to the largest structures and superstructures making up the Universe has an amazing story to tell, if only we can figure out its secrets.
Image credit: Boylan-Kolchin et al. (2009) for the Millenium-II simulation; MPA Garching.
When I first learned some of them for myself, I was a graduate student, immersed in the minutiae and…
esiegel | August 23, 2012"It is always wise to look ahead, but difficult to look further than you can see." -Winston Churchill
We've come a long way in this Universe. Over the past 13.7 billion years, we've formed the light elements out of a sea of protons and neutrons, cooled and expanded to form neutral atoms for the first time, gravitationally collapsed hydrogen and helium gas clouds to form the first stars, borne witness to generations of stellar deaths and rebirths, lived through the formation of hundreds of billions of galaxies and the clustering together of thousands or more galaxies into clusters, filaments,…
esiegel | August 17, 2012"We don’t understand how a single star forms, yet we want to understand how 10 billion stars form." -Carlos Frenk
The Universe has been around for a long time: nearly 14 billion years, to the best of our knowledge. When it was very young, there were absolutely zero stars in it, while today, there are hundreds of billions of galaxies, each of which contains anywhere from a few billion to many trillions of stars.
Image credit: NASA, ESA, and the Hubble Heritage (STScI / AURA) - ESA / Hubble Collaboration
The galaxy shown above, NGC 2841, is very similar to our own Milky Way. Approximately the…
esiegel | August 9, 2012"Who are we? We find that we live on an insignificant planet of a humdrum star lost in a galaxy tucked away in some forgotten corner of a universe in which there are far more galaxies than people." -Carl Sagan
Our night sky, quite literally, is our window to the Universe.
Image credit: Miloslav Druckmuller, Brno University of Technology.
Well, it's kind of a window to the Universe. I say only "kind of" because, with the exception of those two faint, fuzzy clouds in the lower right, everything else visible in the image above is part of our own Milky Way galaxy. In fact, practically…
esiegel | July 30, 2012"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…
esiegel | July 25, 2012"If you don't like what you're doing, you can always pick up your needle and move to another groove." -Timothy Leary
Up in the night sky, shortly after sunset, the night sky holds some spectacular sights. Some are permanent, some are transient, some have been known for thousands of years, and some are still being discovered. Looking to the west after sunset tonight, this is what you're likely to see.
Image credit: Me, using Stellarium, available free at http://stellarium.org.
The Big Dipper, perhaps the most famous collection of seven stars in the night sky, looms large over the horizon. As…
esiegel | July 19, 2012This is an enhanced version (with some upgraded images and text) of an article I first wrote over two years ago. It is just as valid today as it was back then, only today, I have a special offer to go with it. Next week, a bunch of cosmologists and myself are getting together and all writing about dark energy. And I want you to have your say.
So at the end of this post, ask your dark energy questions. Ask anything and everything you ever wanted to know about dark energy. I'll choose the best one (or, space & time permitting, more than one) and write a special post on it for you then.…
esiegel | June 12, 2012"I went into a clothing store, and the lady asked me what size I was. I said, 'Actual'. I'm not to scale." -Demitri Martin
When you look out at the Universe, what you can see is limited, at the most fundamental level, by the size of what you look with. This is why you can see dimmer objects at night -- when your pupils are dilated -- than you can when your pupils are constricted.
Image credit: National Institute of Health.
This same principle that applies to your eyes applies to telescopes as well. As telescopes have grown in size, so has our ability to see deeper into the Universe, as we…
milhayser | June 1, 2012
On Dynamics of Cats, Steinn Sigurðsson sifts through Hubble's vast catalog of stars, gas, and galaxies, looking for a diamond in the rough. Many images captured by the Hubble Space Telescope have never really been looked at; Sigurðsson says "In some cases the PI died before doing so. More usually these are engineering test images, or 'parallel images,' where a second camera was set to take images of wherever it happened to be pointed." The European Space Agency wants your help to search through these pictures. In 2004, Hubble resolved the famous Ultra Deep-Field with 10,000 galaxies across…
esiegel | May 31, 2012"Space is big. You just won't believe how vastly, hugely, mind- bogglingly big it is. I mean, you may think it's a long way down the road to the chemist's, but that's just peanuts to space." -Douglas Adams
Here inside the Milky Way galaxy, all you need are some dark skies and a decent set of eyes, and you'll be greeted of a spectacular, close-up view of the galaxy you inhabit.
Image Credit: ESO / Stephane Guisard, from http://www.astrosurf.com/sguisard/
But getting a handle on the size and scale of our Milky Way? Perhaps paradoxically, that's a question we're still figuring out the answers…