Thanks to NASA's Wilkinson Microwave Anisotropy Probe (WMAP), a satellite that detects microwave light from the big bang, astrophysicists were able to confirm a few of their long-standing theories—and in doing so paint a clearer picture of the birth of the universe.
Using WMAP, researchers measured microwaves pointing in different directions and their polarization across the sky. The polarization was a product of photons left over from the big bang colliding with free electrons, which came from neutral atoms illuminated by the first stars. This data helped verify the emergence of stars 400 million years after the big bang.
Microwave measurements also solidified the theory of "inflation," or the idea that the universe expanded from the size of a marble to it's current expansive, untold size in 10 -35 seconds—or, if you like zeros, 0.0000000000000000000000000000000001 seconds. —Adam Raymond
The expansion of the universe, as interpreted with WMAP.