Launch of Wilkinson Microwave Anisotropy Probe

The Wilkinson Microwave Anisotropy Probe, or WMAP, was a NASA space observatory built to measure tiny temperature differences in the cosmic microwave background, the faint afterglow of the Big Bang. It was launched on a Delta II rocket and placed at the second Lagrange point, about 1.5 million kilometers from Earth, where it could observe the sky with little interference. The mission was named in honor of the cosmologist David Wilkinson. Its detailed maps led to precise estimates of the age of the universe, about 13.8 billion years, and of the proportions of ordinary matter, dark matter and dark energy. WMAP also supported the idea of cosmic inflation. Observations ended in 2010, and the European Planck satellite later refined the results.

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