Planck

Mission Profile

Planck was an ESA space observatory launched on 14 May 2009 aboard an Ariane 5 ECA to the Sun-Earth L2 Lagrange point, designed to map the temperature anisotropies and polarization of the cosmic microwave background radiation across the entire sky with unprecedented precision. Its two instruments — the Low Frequency Instrument (LFI) and High Frequency Instrument (HFI) — mapped the CMB in nine frequency bands, with HFI cooled to just 0.1 Kelvin to achieve the extreme sensitivity required. Planck's final cosmological results, released between 2013 and 2020, provided the most precise measurements of the universe's age (13.8 billion years), its composition (5% ordinary matter, 27% dark matter, 68% dark energy), and its geometry to date. The mission provided definitive statistical evidence that the universe's primordial density fluctuations match the predictions of inflationary cosmology.