COBE (astronomy): Difference between revisions
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==Ripples in the space-time fabric== | ==Ripples in the space-time fabric== | ||
One of the most significant aspects of the COBE data was gathered from the DMR (Differential Microwave Radiomters) which | One of the most significant aspects of the COBE data was gathered from the DMR (Differential Microwave Radiomters) which measured difference in radiation. This variation, or anisotropy, in the backgound radiation consists of small temperature fluctuations in the blackbody radiation left over from the Big Bang. The average temperature of CMB radiation radiation is 2.725 degrees Kelvin.<ref>[http://www.astro.ucla.edu/~wright/CMB-DT.html Cosmic Microwave Background Anisotropy] Professor Edward L. Wright, UCLA Astronomy faculty.</ref> The variations in the temperature are very small, thousandths of degrees. | ||
==References== | ==References== | ||
Revision as of 00:43, 30 July 2007
COBE or Cosmic Background Explorer satellite, was launched on November 18, 1989. COBE was designed and developed to investigate the origins of the universe and succeeded in producing images of the universe as it would have been in its infancy some 13.7 billion years ago. [1] The accomplishments of the COBE were so significant that COBE’s originators, John C. Mather (NASA Goddard Space Flight Center) and George F. Smoot (Lawrence Berkeley National Laboratory and the University of California at Berkeley) were awarded the 2006 Nobel Prize for physics.[2]
Instrumentation
COBE was developed by NASA's Goddard Space Flight Center to measure the diffuse infrared and microwave radiation from the early universe. To accomplish this, COBE carried three instruments:
- Diffuse Infrared Background Experiment (DIRBE) to search for the cosmic infrared background radiation;[3][4][5]
- Differential Microwave Radiometer (DMR) to map the cosmic radiation and variations in the radiation;[6]
- Far Infrared Absolute Spectrophotometer (FIRAS) to compare the spectrum of the cosmic microwave background radiation with blackbody radiation.[7]
The extent and precision of the data gathered has shifted the entire field of cosmology. So much so, that the Nobel Foundation of the Royal Swedish Academy of Sciences, went so far as to say, "the COBE-project can also be regarded as the starting point for cosmology as a precision science: For the first time cosmological calculations (like those concerning the relationship between dark matter and ordinary, visible matter) could be compared with data from real measurements. This makes modern cosmology a true science (rather than a kind of philosophical speculation, like earlier cosmology)."[8]
Theoretical Rationale for COBE
The initial premise of the COBE research was that the universe had originated in a sudden expansion from a submicroscopically small point, the Big Bang Theory. The competing theory, called the Steady State Theory, maintained that ours was a consistent and unchanging universe which neither grew smaller or bigger and had never come into being—it was timeless with neither end or beginning. The Big Bang theorist maintained that the universe was expanding, it had begun from something else and could conceivably come to an end.
The Big Bang Theory could be supported if there was evidence of background radiation (referred to as cosmic microwave background radiation, CMB radiation) permeating the entire universe—leftover radiation. The leftover radiation would be evidence that the universe had a beginning at which time it had been filled with intense radiation. This state would have been long before the appearance of matter—elements, gases, stars and galaxies. Although CMB radiation was originally predicted in 1948 by Georgiy “George” Antonovich Gamow,[9] it was not until 1964 that Arno A. Penzias and Robert W.Wilson, researchers at AT&T's Bell Laboratory (Holmdel, N. J. USA), discovered that there is CMB radiation evident in all directions from Earth. A clear example is the radiation evident on a TV screen. Much of the black and white static is in fact CMB, photons of energy still cooling after the Big Bang.[10]
Ripples in the space-time fabric
One of the most significant aspects of the COBE data was gathered from the DMR (Differential Microwave Radiomters) which measured difference in radiation. This variation, or anisotropy, in the backgound radiation consists of small temperature fluctuations in the blackbody radiation left over from the Big Bang. The average temperature of CMB radiation radiation is 2.725 degrees Kelvin.[11] The variations in the temperature are very small, thousandths of degrees.
References
- ↑ Universe Evolution Image from Smoot Group representing the range of time for the COBE background radiation map
- ↑ George Smoot Wins Nobel Prize in Physics
- ↑ DIRBE
- ↑ DIRBE Galactic plane maps shows various exposures depicting the plane of the galaxy in wavelengths from 1.25 to 12 microns
- ↑ DIRBE Galactic plane maps shows various exposures depicting the plane of the galaxy in wavelengths from 25 to 240 microns
- ↑ DMR
- ↑ FIRAS
- ↑ The Nobel Prize in Physics 2006 Information for the public. p. 5. Royal Swedish Academy of Sciences Accessed 30.07.07
- ↑ Alpher, R. A.; Bethe, H.; Gamow, G. (1948). The Origin of Chemical Elements, Physical Review, vol. 73, Issue 7, pp. 803-804
- ↑ Traversing the Universe Castelvecchi, D. (2005) “Let it Rain” Symmetry. Vol 2:1, Feb. A Fermilab SLAC publication.
- ↑ Cosmic Microwave Background Anisotropy Professor Edward L. Wright, UCLA Astronomy faculty.
External Links
- COBE National Aeronautics and Space Administration
- COBE Smoot Group Astrophysics and Cosmology
- “The Big Bang Model” Bernard Sadoulet Lecture, Smoot Group Astrophysics and Cosmology. Places the COBE findings within three different approaches to support the Big Bang model.
- George Smoot Nobel Lecture video
- George Smoot Nobel interview video
- John Mather Nobel Lecture video
- John Mather Nobel interview video
- Arno Penzias and Robert W. Wilson Nobel bio and speeches
- “Cosmic Microwave Background Radiation" Robert Woodrow Wilson Nobel lecture
- “The Origin of Elements” Arno Penzias Nobel Lecture
- Cosmic Background Explorer (COBE) Team Wins Gruber Prize Berkely Lab Research News. Describes the mission findings and significance.