Observing the cosmic microwave background
We can’t see the Big Bang itself, but the CMB is the next best thing
COBE
The first space mission designed to study the CMB was NASA’s Cosmic Background Explorer, launched in 1989. It found the CMB is much more uniform across the sky than expected.
WMAP
A second NASA spacecraft, the Wilkinson Microwave Anisotropy Probe, mapped the CMB between 2001 and 2010, confirming the astonishing uniformity.
Planck
Planck was the European Space Agency’s follow on to WMAP. Operating from 2009 to 2013, it remapped the CMB with higher sensitivity and resolution than its predecessor.