fluctuation

"The radiation left over from the Big Bang is the same as that in your microwave oven but very much less powerful. It would heat your pizza only to -271.3°C, not much good for defrosting the pizza, let alone cooking it." -Stephen Hawking One of the most powerful predictions of the Big Bang -- the fact that our cold, star-and-galaxy-rich, slowly-expanding Universe came from a hot, dense, much more homogeneous state -- was the existence of a bath of leftover radiation that should be detectable, even today. Image credit: Pearson / Addison Wesley, retrieved from Jill Bechtold. Back when the…

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…