The cosmic microwave background, or relic radiation, is microwave radiation that fills all space in the observable universe. With a standard optical telescope, the background space between stars and galaxies is almost completely dark. However, a sufficiently sensitive radio telescope detects a faint background glow that is almost uniform and is not associated with any star, galaxy, or other object. This glow is strongest in the microwave region of the radio spectrum. The accidental discovery of the CMB in 1965 by American radio astronomers Arno Penzias and Robert Wilson was the culmination of work initiated in the 1940s.
The Wilkinson Microwave Anisotropy Probe (WMAP), originally known as the Microwave Anisotropy Probe, was a NASA spacecraft operating from 2001 to 2010 which measured temperature differences across the sky in the cosmic microwave background (CMB) – the radiant heat remaining from the Big Bang. Headed by Professor Charles L. Bennett of Johns Hopkins University, the mission was developed in a joint partnership between the NASA Goddard Space Flight Center and Princeton University. The WMAP spacecraft was launched on 30 June 2001 from Florida. The WMAP mission succeeded the COBE space mission and was the second medium-class (MIDEX) spacecraft in the NASA Explorer program. In 2003, MAP was renamed WMAP in honor of cosmologist David Todd Wilkinson (1935–2002), 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 Cosmic Background Explorer, also referred to as Explorer 66, was a NASA satellite dedicated to cosmology, which operated from 1989 to 1993. Its goals were to investigate the cosmic microwave background radiation of the universe and provide measurements that would help shape our understanding of the cosmos.
The Sunyaev–Zeldovich effect is the spectral distortion of the cosmic microwave background (CMB) through inverse Compton scattering by high-energy electrons in galaxy clusters, in which the low-energy CMB photons receive an average energy boost during collision with the high-energy cluster electrons. Observed distortions of the cosmic microwave background spectrum are used to detect the disturbance of density in the universe. Using the Sunyaev–Zeldovich effect, dense clusters of galaxies have been observed.
Observational cosmology is the study of the structure, the evolution and the origin of the universe through observation, using instruments such as telescopes and cosmic ray detectors.
The Cosmic Background Imager was a 13-element interferometer perched at an elevation of 5,080 metres at Llano de Chajnantor Observatory in the Chilean Andes. It started operations in 1999 to study the cosmic microwave background radiation and ran until 2008.
BOOMERanG experiment was an experiment that flew a telescope on a (high-altitude) balloon and measured the cosmic microwave background radiation of a part of the sky during three sub-orbital flights. It was the first experiment to make large, high-fidelity images of the CMB temperature anisotropies, and is best known for the discovery in 2000 that the geometry of the universe is close to flat, with similar results from the competing MAXIMA experiment.
Llano de Chajnantor Observatory is the name for a group of astronomical observatories located at an altitude of over 4,800 m (15,700 ft) in the Atacama Desert of northern Chile. The site is in the Antofagasta Region approximately 50 kilometres (31 mi) east of the town of San Pedro de Atacama. The exceptionally arid climate of the area is inhospitable to humans, but creates an excellent location for millimeter, submillimeter, and mid-infrared astronomy. This is because water vapour absorbs and attenuates submillimetre radiation. Llano de Chajnantor is home to the largest and most expensive astronomical telescope project in the world, the Atacama Large Millimeter Array (ALMA). Llano de Chajnantor and the surrounding area has been designated as the Chajnantor Science Reserve by the government of Chile.
George Fitzgerald Smoot III is an American astrophysicist, cosmologist, Nobel laureate, and the second contestant to win the $1 million prize on Are You Smarter than a 5th Grader? He won the Nobel Prize in Physics in 2006 for his work on the Cosmic Background Explorer with John C. Mather that led to the "discovery of the black body form and anisotropy of the cosmic microwave background radiation".
RELIKT-1 from Russian: РЕЛИКТ-1 was a Soviet cosmic microwave background anisotropy experiment launched on board the Prognoz 9 satellite on 1 July 1983. It operated until February 1984. It was the first CMB satellite and measured the CMB dipole, the Galactic plane, and gave upper limits on the quadrupole moment.
The Degree Angular Scale Interferometer (DASI) was a telescope installed at the U.S. National Science Foundation's Amundsen–Scott South Pole Station in Antarctica. It was a 13-element interferometer operating between 26 and 36 GHz in ten bands. The instrument is similar in design to the Cosmic Background Imager (CBI) and the Very Small Array (VSA). In 2001 The DASI team announced the most detailed measurements of the temperature, or power spectrum of the cosmic microwave background (CMB). These results contained the first detection of the 2nd and 3rd acoustic peaks in the CMB, which were important evidence for inflation theory. This announcement was done in conjunction with the BOOMERanG and MAXIMA experiment. In 2002 the team reported the first detection of polarization anisotropies in the CMB.
Rodney Deane Davies CBE FRS was a Professor of Radio Astronomy at the University of Manchester. He was the President of the Royal Astronomical Society in 1987–1989, and the Director of Jodrell Bank Observatory in 1988–97. He is best known for his research on the Cosmic microwave background and the 21cm line.
The Millimeter Anisotropy eXperiment IMaging Array (MAXIMA) experiment was a balloon-borne experiment funded by the United States NSF, NASA, and Department of Energy, and operated by an international collaboration headed by the University of California, to measure the fluctuations of the cosmic microwave background. It consisted of two flights, one in August 1998 and one in June 1999. For each flight the balloon was started at the Columbia Scientific Balloon Facility in Palestine, Texas and flew to an altitude of 40,000 metres for over 8 hours. For the first flight it took data from about 0.3 percent of the sky of the northern region near the Draco constellation. For the second flight, known as MAXIMA-II, twice the area was observed, this time in the direction of Ursa Major.
The Mobile Anisotropy Telescope (MAT), also known as the Mobile Anisotropy Telescope on Cerro Toco was a ground-based radio telescope experiment to measure the anisotropy of the cosmic microwave background (CMB). The experiment was conducted at an observation site on the southern slopes of Cerro Toco in the Atacama Desert of northern Chile. It was a collaboration between the physics departments at Princeton University and the University of Pennsylvania.
The Saskatoon experiment was a ground-based telescope experiment to measure the anisotropy of the cosmic microwave background (CMB) at multipole moments between 60 and 360. It was named after Saskatoon, Saskatchewan, Canada, where the experiment took place, occurring in the Canadian winters of 1993 to 1995.
The Viper telescope was a 2-metre telescope used to observe the submillimetre band from the South Pole. This telescope was located at the Center for Astrophysical Research, also known as (CARA), in the Amundsen-Scott station in Antarctica. The project was operated by many scientists; the team leader, Dr. Jeffrey Peterson, is a Carnegie Mellon astrophysicist.
In modern cosmological theory, diffusion damping, also called photon diffusion damping, is a physical process which reduced density inequalities (anisotropies) in the early universe, making the universe itself and the cosmic microwave background radiation (CMB) more uniform. Around 300,000 years after the Big Bang, during the epoch of recombination, diffusing photons travelled from hot regions of space to cold ones, equalising the temperatures of these regions. This effect is responsible, along with baryon acoustic oscillations, the Doppler effect, and the effects of gravity on electromagnetic radiation, for the eventual formation of galaxies and galaxy clusters, these being the dominant large scale structures which are observed in the universe. It is a damping by diffusion, not of diffusion.
The Yuan-Tseh Lee Array for Microwave Background Anisotropy, also known as the Array for Microwave Background Anisotropy (AMiBA), is a radio telescope designed to observe the cosmic microwave background and the Sunyaev-Zel'dovich effect in clusters of galaxies.
POLARBEAR is a cosmic microwave background polarization experiment located in the Atacama Desert of northern Chile in the Antofagasta Region. The POLARBEAR experiment is mounted on the Huan Tran Telescope (HTT) at the James Ax Observatory in the Chajnantor Science Reserve. The HTT is located near the Atacama Cosmology Telescope on the slopes of Cerro Toco at an altitude of nearly 5,200 m (17,100 ft).
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