WMAP

Differential microwave radiometers fed by two back-to-back telescopes measured CMBcosmic microwave backgroundThermal radiation released 380,000 years after the Big Bang, now at 2.7255 K and peaking near 160 GHz. Its temperature and polarisation anisotropies, at the 10⁻⁵ level, constrain the content and geometry of the Universe. temperature and polarisationpolarimetryMeasuring the polarisation of incoming radiation. It encodes magnetic-field geometry, scattering and emission mechanisms; in the CMB it separates E- and B-mode patterns. anisotropy over the whole sky in five bands from 22 to 90 GHz, from L2Lagrange pointA point where the gravity of two bodies and the orbital motion balance. Sun–Earth L2, 1.5 million km beyond Earth, keeps Sun, Earth and Moon on one side: a stable thermal environment for passive cooling and an unobstructed view of most of the sky. (2001–2010). Its nine-year results established the six-parameter ΛCDMΛCDMThe standard cosmological model: a flat universe with dark energy as a cosmological constant (Λ), cold dark matter and ordinary matter, fit by six parameters. model, with an age of 13.77 billion years and a nearly scale-invariant primordial spectrum.

Operator

NASA

Orbit

Sun–Earth L2

Passband

22 GHz – 90 GHz

Launch

30 June 2001

End

19 August 2010