clustering

"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…

"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…

Some of you who've been following astronomy for awhile might remember this report, where a group of astronomers reported finding a giant "void" in the Universe. What is a void? Well, galaxies are distributed pretty randomly, but because of gravity, they cluster together. A small example is our local group which looks like this, and a larger example is the Virgo cluster, which is about 1,000 times as massive as our local group, and looks like this: Well, a void is the opposite of a cluster, where you have a large volume of space that's simply empty of galaxies and matter. This press release…