Wilkinson Microwave Anisotropy Probe

In 2003, MAP was renamed WMAP in honor of cosmologist David Todd Wilkinson (1935–2002),[7] who had been a member of the mission's science team.

After nine years of operations, WMAP was switched off in 2010, following the launch of the more advanced Planck spacecraft by European Space Agency (ESA) in 2009.

The WMAP data are very well fit by a universe that is dominated by dark energy in the form of a cosmological constant.

[12] Of the all-time most referenced papers in physics and astronomy in the INSPIRE-HEP database, only three have been published since 2000, and all three are WMAP publications.

Page Jr., and David N. Spergel, the latter both of Princeton University, shared the 2010 Shaw Prize in astronomy for their work on WMAP.

The 2018 Breakthrough Prize in Fundamental Physics was awarded to Bennett, Gary Hinshaw, Norman Jarosik, Page, Spergel, and the WMAP science team.

For example, the largest angular-scale measurement, the quadrupole moment, is somewhat smaller than the Model would predict, but this discrepancy is not highly significant.

The WMAP objective was to measure the temperature differences in the Cosmic Microwave Background (CMB) radiation.

The anisotropies then were used to measure the universe's geometry, content, and evolution; and to test the Big Bang model, and the cosmic inflation theory.

The map required the fewest systematic errors, no correlated pixel noise, and accurate calibration, to ensure angular-scale accuracy greater than its resolution.

They are shaped for optimal performance: a carbon fibre shell upon a Korex core, thinly-coated with aluminium and silicon oxide.

The telescope's data are relayed daily via a 2-GHz transponder providing a 667 kbit/s downlink to a 70 m (230 ft) Deep Space Network station.

The telescope's position is maintained, in its three axes, with three reaction wheels, gyroscopes, two star trackers and Sun sensors, and is steered with eight hydrazine thrusters.

[22] Afterwards, it effected three Earth-Moon phase loops, measuring its sidelobes, then flew by the Moon on 30 July 2001, en route to the Sun-Earth L2 Lagrange point, arriving there on 1 October 2001, becoming the first CMB observation mission posted there.

[20] Locating the spacecraft at Lagrange 2, (1,500,000 km (930,000 mi) from Earth) thermally stabilizes it and minimizes the contaminating solar, terrestrial, and lunar emissions registered.

To view the entire sky, without looking to the Sun, the WMAP traces a path around L2 in a Lissajous orbit ca.

[21] The WMAP instrument consists of pseudo-correlation differential radiometers fed by two back-to-back 1.5 m (4 ft 11 in) primary Gregorian reflectors.

[23] The WMAP observed in five frequencies, permitting the measurement and subtraction of foreground contamination (from the Milky Way and extra-galactic sources) of the CMB.

The spectral properties of these emissions contribute different amounts to the five frequencies, thus permitting their identification and subtraction.

In addition, an image of the early universe, that "contains such stunning detail, that it may be one of the most important scientific results of recent years" was presented.

[24] The team also examined Milky Way emissions at the WMAP frequencies, producing a 208-point source catalogue.

The data included temperature and polarization measurements of the CMB, which provided further confirmation of the standard flat Lambda-CDM model and new evidence in support of inflation.

[10] The WMAP five-year data was combined with measurements from Type Ia supernova (SNe) and Baryon acoustic oscillations (BAO).

It seems most likely these are due to other effects, with the report mentioning uncertainties in the precise beam shape and other possible small remaining instrumental and analysis issues.

These oval images present the temperature distribution derived by the WMAP team from the observations by the telescope during the mission.

[citation needed] The original timeline for WMAP gave it two years of observations; these were completed by September 2003.

Many are aimed at searching for the B-mode polarization expected from the simplest models of inflation, including The E and B Experiment (EBEX), Spider, BICEP and Keck Array (BICEP2), Keck, QUIET, Cosmology Large Angular Scale Surveyor (CLASS), South Pole Telescope (SPTpol) and others.

On 21 March 2013, the European-led research team behind the Planck spacecraft released the mission's all-sky map of the cosmic microwave background.

Apparently, these ripples gave rise to the present vast cosmic web of galaxy clusters and dark matter.

On 5 February 2015, new data was released by the Planck mission, according to which the age of the universe is 13.799 ± 0.021 billion years and the Hubble constant is 67.74 ± 0.46 (km/s)/Mpc.

The universe's timeline, from the Big Bang to the WMAP
A comparison of the sensitivity of WMAP with COBE and Penzias and Wilson's telescope (simulated data)
WMAP spacecraft diagram
Illustration of WMAP's receivers
One-year WMAP image of background cosmic radiation (2003)
Three-year WMAP image of background cosmic radiation (2006)
Five-year WMAP image of background cosmic radiation (2008)
7-year WMAP image of background cosmic radiation (2010)
9-year WMAP image of background cosmic radiation (2012)
Interviews with Charles Bennett and Lyman Page about WMAP
Comparison of CMB results from COBE , WMAP and Planck – 21 March 2013