large scale structure
esiegel | August 16, 2013"On a cosmic scale, our life is insignificant, yet this brief period when we appear in the world is the time in which all meaningful questions arise." -Paul Ricoeur
Ask anyone who's looked up at a dark sky on a clear, moonless night, and you'll immediately hear tales about how incomprehensibly vast the Universe is.
Image credit: Randy Halverson, flickr user dakotalapse, from http://dakotalapse.com/.
But what you're looking at isn't much of the Universe at all. In fact, practically every point of light you see, including the vast swath of stars too dim to individually resolve, comes from…
esiegel | January 18, 2013"The cosmos is all that is or ever was or ever will be. Our feeblest contemplations of the Cosmos stir us—there is a tingling in the spine, a catch in the voice, a faint sensation, as if a distant memory, or falling from a height. We know we are approaching the greatest of mysteries." -Carl Sagan
If you looked out at the planets in the Solar System orbiting our Sun, you'd expect that if you know where they are right now and how quickly they're moving, you can figure out exactly where they're going to be at any time-and-date arbitrarily far into the future. That's the great power that comes…
esiegel | December 7, 2012"If you wish to make an apple pie from scratch, you must first invent the Universe." -Carl Sagan
The Universe is a lot like an extremely intricate cake. We view it today as a snapshot in time, now that it's complete.
Image credit: Blogger user Hilly of http://makesbakesfakes.blogspot.com/.
We can view the whole thing from one point of view, determined by where we happened to be located. But we can also look intricately inside certain sections of it, so long as we have the right tools.
Image credit: Blogger user Hilly of http://makesbakesfakes.blogspot.com/.
But if we truly want to…
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 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 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.…