The Planck mission was a space observatory operated by the European Space Agency (ESA). The mission was named after the German physicist Max Planck. It was launched on May 14, 2009, and operated until its batteries were depleted on October 23, 2013. Its nominal lifetime was four years and it completed two full surveys of the sky: the first at high frequency and the second at low frequency.
The primary scientific goals of the mission were to make precise measurements of the cosmic microwave background (CMB) radiation anisotropies in order to better understand our Universe. The CMB is believed to be leftover radiation from the Big Bang, so studying it can give us insight into conditions in the early Universe. Other objectives included measuring or setting limits on cosmological parameters such as inflation, dark energy, neutrino masses, etc.
The Planck spacecraft carried two instruments: the High Frequency Instrument (HFI), which observed in six wavelength bands between 100 and 857 GHz; and the Low Frequency Instrument (LFI), which observed in three wavelength bands between 30 and 70 GHz. Data from both instruments were used in this article.
Planck’s observations have made numerous contributions to cosmology since they were released in March 2013. One of the most important has been providing strong evidence for inflationary theory – specifically that our Universe underwent a period of rapid expansion immediately after its formation 13.8 billion years ago. These results have also helped constrain other cosmological parameters such as dark energy and neutrino masses. Finally, Planck’s data has allowed astronomers to produce some of the most detailed maps ever made of the CMB sky!