The most extensive measurements of the relic radiation from the early universe are currently being made by the Wilkinson Microwave Anisotropy Probe, a satellite launched in 2001. WMAP consists of an assembly of sensitive microwave receivers to precisely characterize the afterglow of the big bang. Observations from WMAP have confirmed that the space-time geometry of the universe is flat, like a sheet of paper, and have then yielded the age of the universe— about 13.7 billion years—with a precision of about one percent. Further investigations of the variation of the microwave background radiation at small angular scales have shown that normal visible matter plus cold dark matter can account for only about 30 percent of the content of our universe. The remaining 70 percent is dark energy. WMAP has accurately determined the content of normal visible matter at only four percent, in remarkable agreement with the value determined using data from the much earlier era of nucleosynthesis. The whole revolutionary picture of our universe, including dark matter and dark energy, matches beautifully with the WMAP data.

The flight hardware and software for WMAP are produced in a partnership between NASA's Goddard Space Flight Center and Princeton University, under the scientific supervision of a team whose institutions also include UCLA, the University of Chicago, the University of British Columbia, and Brown University.

Image Credit: WMAP