Soon after Hubble announced his findings, astronomers raced to measure the exact expansion rate of the universe. By measuring the flux of Type IA supernovae at different distances, they calculated the Hubble Constant to be 71 kilometers per second per megaparsec. More importantly, however, when they compared that data to different types of cosmologies, they found that our universe did not seem to have a matter density high enough to re-collapse and seemed to be accelerating due to some mysterious, unknown repulsive vacuum energy [11]. …show more content…
For this reason, it was not until results from the Wilkinson Microwave Anisotropy Probe (WMAP) satellite were published that all lingering doubts about the existence of dark energy were eliminated. By giving us the most detailed picture of the CMB, WMAP data confirmed what other observations were already suggesting: ordinary matter, which is really the only type of matter we know about, makes up only four percent of the entire universe. The rest is dark matter and dark energy, the former composing 23 percent of the universe and the latter 73 percent