Planck (spacecraft)

Planck was a space observatory operated by the European Space Agency (ESA) from 2009 to 2013.
It mapped the anisotropies of the cosmic microwave background (CMB) at microwave and infra-red frequencies, with high sensitivity and small angular resolution.
The mission improved on observations made by the NASA Wilkinson Microwave Anisotropy Probe (WMAP). "Planck" provided a major source of information about cosmology and astrophysics. It tested theories of the early Universe and the origin of cosmic structure.
Since the end of its mission, "Planck" has made the most precise measurements of several key numbers. These include the average density of ordinary matter and dark matter in the Universe, and the age of the universe. Planck is now switched off.