COBE


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COBE:

see infrared astronomyinfrared astronomy,
study of celestial objects by means of the infrared radiation they emit, in the wavelength range from about 1 micrometer to about 1 millimeter. All objects, from trees and buildings on the earth to distant galaxies, emit infrared (IR) radiation.
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COBE

(koh -bee) Abbrev. for Cosmic Background Explorer. A NASA orbiting satellite launched Nov. 18 1989 and dedicated to the study of the cosmic microwave background radiation, and hence to cosmology. The mission ran for just over four years, being terminated by NASA on Dec. 23 1993.

COBE's scientific payload consisted of three instruments shielded from the adverse thermal and radiation effects of the Sun and Earth. Two cryogenically cooled instruments observed the sky at infrared wavelengths. DIRBE, the diffuse infrared background experiment, mapped the sky at 10 wavelengths over 1–300 μm in search of the cumulative uniform glow from earliest luminous objects. FIRAS, the far-infrared absolute spectrophotometer, measured the average temperature of the background with unprecedented precision: it showed the spectrum of the microwave background to be a perfect black body curve characteristic of a temperature of 2.735 ± 0.06 K. FIRAS was turned off after 10 months of flight when the helium coolant ran out.

The third detector, the DMR (differential microwave radiometer), consisted of six differential radiometers observing the sky at three radio wavelengths – 3.3, 5.7, and 9.5 mm. They made whole-sky surveys and were designed to detect any fluctuations in the brightness of the microwave background.

The microwave background is not completely uniform, showing a slight dipole anisotropy with an enhancement of one part in a thousand in the direction of the Galaxy's motion and an equal and opposite deficit in the opposite part of the sky. This results from the real motion of the Galaxy relative to the fixed background. It was announced in April 1992 that careful statistical analysis of the COBE measurements also revealed even weaker temperature fluctuations of one part in one hundred thousand on scales of ten degrees and larger. These are the imprints of quantum fluctuations in the early Universe. Further study of such fluctuations by such missions as the Wilkinson Microwave Anisotropy Probe have served to constrain cosmological models that determine how the early inhomogeneities collapsed to form the large-scale structure we see in today's Universe.

References in periodicals archive ?
COBE proved that astronomers could detect the EBL; the next challenge was measuring it precisely enough to make conclusions about the distant universe.
As for the COBE Far Infrared Absolute Spectrophotometer, FIRAS (see Figure 1), it had seemingly produced the most perfect blackbody spectrum ever recorded [23-45].
The final COBE and postacquisition transfer regulations appear to permit A to effect a tax-free spin-off of Y to P without having the initial triangular C reorganization disqualified or recharacterized.
Therefore, our suggestion of the relativistic lowering of the temperature of the Penzias-Wilson microwave background due to the Doppler-like anisotropic effect on it [11], is in good agreement with that observed in the COBE and WMAP space missions.
The COBE images are our first look at the baby picture of the universe," says David N.
4) In addition, the COBE requirement no longer applies to bar the new target from disposing of a significant portion of its assets following the transaction.
In the gas phase, the dimer is known to have a fundamental frequency in the far infrared [7], very close to the region sampled by the COBE FIRAS instrument [13].
added, "This is a tremendous accomplishment for John and for the COBE team.
For recapitalizations, the IRS has long held that the COI and COBE requirements do not apply to transactions involving only a single corporation.
COBE Development today broke ground on Camelback 101 Professional Plaza, a new office development located on four and a half acres on the southeast corner of Camelback Road and Loop 101 Agua Fria Freeway in Phoenix.
It is shown that the EMB decreases with altitude so that the density of its energy at the altitude of the COBE orbit (900km) is 0.
who will represent the COBE team at the opening ceremony of the International Astronomical Union's General Assembly in Prague on August 15.