Last time I talked a little bit about the CMBR, which is one of the major arguments for the big bang theory (not the show mind you), but how can scientists be sure that there is this uniform level of energy all around our universe, even in the spaces between galaxies?
Once the beginnings of the CMBR were detected there was a great push to create a satellite with the capability of measuring it more completely. Why would they use a satellite? It just so happens that as the sky above us protects us from harmful radiation both from our star (the sun) it also acts like a filter, removing some kinds of light (or radiation) that we use to "see" in space. In the case of the CMBR we want to see microwave radiation (yes the kind in your kitchen, just not as energetic).
So NASA got together with a few other scientists and lauched what is known as the Wilkinson Microwave Anisotropy Probe (lets just call it the WMAP, everyone else does). This probe has been running since 2001 and returning large amounts of microwave data as it orbits our planet earth. Over this time it has measured the temperatures (or concentrations) of the CMBR all across the visible sky. You can see a diagram of the WMAP below.
So really, the CMBR, what scientists have believed to be the "echo" of the very beginning of our universe, is the largest form of basis for cosmologists to tell you how the universe began. The data they use for this comes from the WMAP, a probe that only ready microwave radiation. There are a few other things we need to talk about, before we can determine if these scientists really know what they are talking about.
Next time in the Laymans' Laboratory, redshift, and why everyone thinks the universe was created in an explosion.