NationMaster - Encyclopedia: Cosmic microwave background experiments

Cosmic background radiation spectrum as determined with the COBE satellite, (top) uncorrected, (middle) corrected for the dipole term due to our peculiar velocity, (bottom) corrected for contributions from the dipole term and from our galaxy.

The experiment that discovered the cosmic microwave background was the experiment of Arno Penzias and Robert Woodrow Wilson in which the cosmic microwave background was accidentally discovered at Bell Telephone Laboratories in 1964. See discovery of the cosmic microwave background. The most famous experiment is probably the NASA Cosmic Background Explorer (COBE) satellite that was flown in 1989-1996 is probably the most famous and which made the first detection of the large scale anisotropies (other than the dipole). Inspired by the COBE results, a series of ground and balloon-based experiments measured CMB anisotropies on smaller angular scales over the next decade. The primary goal of these experiments was to measure the scale of the first acoustic peak, which COBE did not have sufficient resolution to resolve. These measurements were able to rule out cosmic strings as a theory of cosmic structure formation, and suggested cosmic inflation was the right theory. The first peak was measured with increasing sensitivity and by 2000 the BOOMERanG experiment reported that the highest power fluctions occur at one degree scales. Together with other cosmological data, these results implied that the geometry of the Universe is flat. A number of ground-based interferometers provided measurements of the fluctuations with higher accuracy over the next three years, including the Very Small Array and the Cosmic Background Imager. In fact, the Cosmic Background Imager has made the first detection of the CMB polarization. When any patch of the sky is observed where no individual sources can be discerned, and the effects of interplanetary dust, and interstellar matter are taken into account, there is still radiation. ... Arno Allan Penzias (born April 26, American physicist. ... Robert Woodrow Wilson (born January 10, 1936) is an American physicist. ... Bell Telephone Laboratories or Bell Labs was originally the research and development arm of the United States Bell System, and was the premier corporate facility of its type, developing a range of revolutionary technologies from telephone switches to specialized coverings for telephone cables, to the transistor. ... For the Nintendo 64 emulator, see 1964 (Emulator). ... NASA Logo Listen to this article Â· (info) This audio file was created from the revision dated 2005-09-01, and does not reflect subsequent edits to the article. ... The Cosmic Background Explorer (COBE), also referred to as Explorer 66, was the first satellite built dedicated to cosmology. ... 1989 (MCMLXXXIX) is a common year starting on Sunday of the Gregorian calendar. ... 1996 (MCMXCVI) is a leap year starting on Monday of the Gregorian calendar, and was designated the International Year for the Eradication of Poverty. ... A cosmic string is a hypothetical 1-dimensional topological defect in the fabric of spacetime. ... Cosmic inflation is the idea, first proposed by Alan Guth in 1981, that the nascent universe passed through a phase of exponential expansion (the inflationary epoch) that was driven by a negative pressure vacuum energy density. ... The Boomerang experiment measured the cosmic microwave background radiation during three sub_orbital balloon flights. ... The intuitive idea of flatness is important in several fields. ... Interferometry is the applied science of combining two or more input points of a particular data type, such as optical measurements, to form a greater picture based on the combination of the two sources. ... The Very Small Array is a 14-element interferometer perched at an elevation of 3000 metres on Tenerife in the Canary Islands. ... The Cosmic Background Imager (or CBI) is a 13-element interferometer perched at an elevation of 5000 metres on the Chajnantor plateau in the Chilean Andes. ...

In June 2001, NASA launched a second CBR space mission, WMAP, to make much more accurate measurements of the large scale anisotropies over the full sky. Results from this mission disclosed in 2003 provided a detailed measurement of the angular power spectrum down to degree scales, tightly constraining various cosmological parameters. The results are broadly consistent with those expected from cosmic inflation as well as various other competing theories, and are available in detail at NASA's data center for Cosmic Microwave Background (CMB) (see links below). Although WMAP provided very accurate measurements of the large angular-scale fluctuations in the CMB (structures about as large in the sky as the moon), it did not have the angular resolution to measure the small scale fluctuations which had been observed using previous ground-based interferometers. 2001 : January - February - March - April - May - June - July - August - September - October - November - December Events: June 5-June 9 - Houston, Texas is devastated by flooding when Tropical Storm Allison dumps 36 inches of rain on the city. ... NASA Logo Listen to this article Â· (info) This audio file was created from the revision dated 2005-09-01, and does not reflect subsequent edits to the article. ... Alternate meaning: WMAP (AM) Artist depiction of the WMAP satellite at the L2 point The Wilkinson Microwave Anisotropy Probe (WMAP) is a NASA satellite whose mission is to survey the sky to measure the temperature of the radiant heat left over from the Big Bang. ... Cosmic inflation is the idea, first proposed by Alan Guth in 1981, that the nascent universe passed through a phase of exponential expansion (the inflationary epoch) that was driven by a negative pressure vacuum energy density. ... Interferometry is the applied science of combining two or more input points of a particular data type, such as optical measurements, to form a greater picture based on the combination of the two sources. ...

A third space mission, the Planck Surveyor, is to be launched in 2007. Planck employs both HEMT radiometers as well as bolometer technology and will measure the CMB on smaller scales than WMAP. Unlike the previous two space missions, Planck is a collaboration between NASA and ESA (the European Space Agency). Its detectors got a trial run at the Antarctic Viper telescope as ACBAR (Arcminute Cosmology Bolometer Array Receiver) experiment – which has produced the most precise measurements at small angular scales to date – and at the Archeops balloon telescope. WMAP image, unrelated to Planck The Planck Surveyor is the third Medium-Sized Mission (M3) of ESAs Horizon 2000 Scientific Programme. ... HEMT stands for High Electron Mobility Transistor, and is also called heterostructure FET (HFET). ... A bolometer is a device for measuring incident electromagnetic radiation. ... The European Space Agency (ESA), established in 1975,is an inter-governmental organisation dedicated to exploration of space with currently 17 member states. ... Redirect page ...

Additional ground-based instruments such as the CLOVER array and South Pole Telescope in Antarctica and the Atacama Cosmology Telescope in Chile will provide additional data not available from satellite observations, possibly including B-mode polarization component. CLOVER array Clover is a new instrument which has been designed to measure the B-mode polarization of the Cosmic Microwave Background down to a sensitivity limited by the foreground contamination due to lensing, allowing the detection of primordial gravitational waves in the Universe. ... The South Pole Telescope or (SPT) is a project whose goal is to build a 10 meter diameter sub-millimeter quality telescope at the South Pole. ... The Atacama Cosmology Telescope (ACT) is currently under construction on Cerro Toco in Chile, and is scheduled to see first light in 2006. ...

List of experiments in approximate chronological order

Each experiment provided improved data quality when compared with previous experiments.

Cosmic Background Explorer - measured the very large scale fluctuations
Saskatoon experiment - an experiment in Saskatchewan
Cosmic Anisotropy Telescope - measured the very small scale fluctuations in small regions of the sky
MAXIMA - measured intermediate scale fluctuations with improved precision
BOOMERanG experiment - measured intermediate scale fluctuations with improved precision
BEAST - A ground-based single dish CMB observatory at the University of California's White Mountain Research station.
Archeops - measured large and intermediate scale with improved precision at the larger scales
Cosmic Background Imager - measured the very small scale fluctuations with improved precision in small regions of the sky
Very Small Array - measured intermediate and small scale fluctuations with improved precision in small regions of the sky
Degree Angular Scale Interferometer - a temperature and polarization telescope at the South Pole
Arcminute Cosmology Bolometer Array Receiver - measured intermediate and small scale fluctuations with improved precision
Wilkinson Microwave Anisotropy Probe - measured intermediate and large scale fluctuations with improved precision
QuaD (ongoing) - measured intermediate scale polarization with improved precision (South Pole).
[Robinson Gravitational Wave Background Telescope (formerly BICEP)] (dec 2005) - measured large scale polarization with improved precision (South Pole).
Atacama Pathfinder EXperiment /SZ - (2005/2006) new telescope, prototype of ALMA, will be used partly to measure small scale fluctuations -part of the APEX experiment which will measure the CMB small scale fluctuations, mainly produce by Sunyaev-Zeldovich effect (SZ effect), for more information see http://bolo.berkeley.edu/apexsz
Atacama Cosmology Telescope - (2006) new telescope for measuring the small scale fluctuations being built in the Atacama Desert in Chile
South Pole Telescope - (2006) a new telescope for measuring the small scale fluctuations and polarization, located at the South Pole
SPIDER (2009?) - balloon-borne, will measure very large scale polarization.
CLOVER - (2008?) - improved precision for small scale fluctuations and B-mode polarization measurements
Planck - (2009?) - will give improved precision and polarization data at all scales

The Cosmic Background Explorer (COBE), also referred to as Explorer 66, was the first satellite built dedicated to cosmology. ... Motto: Multis E Gentibus Vires (From many peoples, strength) Other Canadian provinces and territories Capital Regina Largest city Saskatoon Lieutenant-Governor Lynda M. Haverstock Premier Lorne Calvert (NDP) Area 651,036 kmÂ² (7th) â€¢ Land 591,670 kmÂ² â€¢ Water 59,366 kmÂ² (9. ... The Cosmic Anisotropy Telescope CAT was a three-element interferometer for cosmic microwave background observations at 13 to 17 GHz, based at the Mullard Radio Astronomy Observatory. ... The Boomerang experiment measured the cosmic microwave background radiation during three sub_orbital balloon flights. ... White Mountain is a peak in Mono County, California. ... The Cosmic Background Imager (or CBI) is a 13-element interferometer perched at an elevation of 5000 metres on the Chajnantor plateau in the Chilean Andes. ... The Very Small Array is a 14-element interferometer perched at an elevation of 3000 metres on Tenerife in the Canary Islands. ... Artist depiction of the WMAP satellite at the L2 point The Wilkinson Microwave Anisotropy Probe (WMAP) is a NASA satellite whose mission is to survey the sky to measure the temperature of the radiant heat left over from the Big Bang. ... Alma my refer to: ALMA, Atacama Large Millimeter Array, an array of radio telescopes in Chile. ... WMAP image of the CMB anisotropy,Cosmic microwave background radiation(June 2003) The cosmic microwave background radiation (CMB) is a form of electromagnetic radiation that fills the whole of the universe. ... The Sunyaev-Zeldovich effect (SZ effect or Sunyaev-Zeldovich theory) is due to high energy electrons distorting the cosmic microwave background radiation (CMB) through the inverse Compton effect, in which some of the high energy of the electrons is transferred to the low energy photons. ... The Atacama Cosmology Telescope (ACT) is currently under construction on Cerro Toco in Chile, and is scheduled to see first light in 2006. ... The Atacama desert of Chile is a virtually rainless plateau made up of salt basins (salares), sand, and lava flows, extending from the Andes mountains to the Pacific Ocean. ... The South Pole Telescope or (SPT) is a project whose goal is to build a 10 meter diameter sub-millimeter quality telescope at the South Pole. ... Location of the South Pole in the Antarctic continent. ... CLOVER array Clover is a new instrument which has been designed to measure the B-mode polarization of the Cosmic Microwave Background down to a sensitivity limited by the foreground contamination due to lensing, allowing the detection of primordial gravitational waves in the Universe. ... Planck is a European Space Agency satellite to be launched in 2007. ...

List of experiments in approximate chronological order

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