March 21, 2013
Photos by European Space Agency Planck Collaboration
This image released Thursday shows the evolution of satellites designed to measure ancient light, called the cosmic microwave background, left over from the Big Bang. The three panels show patches of all-sky maps created by space-based missions capable of detecting the cosmic microwave background. The first craft, launched in 1989, at left, is NASA's Cosmic Background Explorer, or COBE. The second satellite, the Wilkinson Microwave Anisotropy Probe, or WMAP, center, was launched in 2001. The third satellite, Planck, was launched in 2009.