The WMAP probe detects signals of the remnant afterglow of the universe when it was just 380,000 years young. While the universe expanded over the next 13 billion years, this light extended to longer wavelengths while losing energy. At present, this light spans within the range of microwaves (23 to 95GHz) which are detectable by modern instruments, such as the WMAP probe in unobstructed space. The all-sky map is an internal linear combination of five frequency maps so computed as to minimize appearance of galactic foreground.
Final legacy data will be released by 2012.
Launched in June 2001, NASA's WMAP (Wilkinson Microwave Anisotropy Probe) spacecraft is a probe designed for the purpose of exploring history and structure of our universe.
After nine years measuring subtle temperature fluctuations in the cosmic microwave background radiation, the WMAP mission unveiled age and composition of the universe with an unparalleled precision of one percent!
According to WMAP data analysis, the universe is 13.75 billion years old and made of mere 4.6% atoms of today's cosmos, further filled with 23 percent dark matter and 72 percent dark energy, the latter probably a feature of vacuum. The nature of both "dark entities" is not yet entirely understood.
WMAP data also revealed a color-coded all-sky map of 13.75 billion years old temperature differences marking the birthplaces of galaxies.