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Topic: Cosmic microwave background radiation


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CMB

In the News (Fri 24 May 19)

  
  Blackbody Radiation
A uniform background radiation in the microwave region of the spectrum is observed in all directions in the sky.
The discovery of the 3K microwave background radiation was one of the crucial steps leading to the calculation of the standard "Big Bang" model of cosmology, its role being that of providing estimates of relative populations of particles and photons.
The scale of the fluctuations is larger than the horizon at the time the background radiation was emitted, indicating that the fluctuations are primordial, dating from a time before the separation of radiation and matter, the transparency point.
hyperphysics.phy-astr.gsu.edu /hbase/bkg3k.html   (947 words)

  
  PlanetPhysics: cosmic microwave background radiation   (Site not responding. Last check: 2007-10-07)
The cosmic microwave background was predicted by George Gamow, Ralph Alpher, and Robert Herman in 1948.
The interpretation of the cosmic microwave background was a controversial issue in the 1960s with some proponents of the steady state theory arguing that the microwave background was the result of scattered starlight from distant galaxies.
The period after the emission of the cosmic microwave background and before the observation of the first stars is semi-humorously referred to by cosmologists as the dark age, and is a period which is under intense study by astronomers (See 21 centimeter radiation).
planetphysics.org /encyclopedia/CosmicMicrowaveBackgroundRadiation.html   (3304 words)

  
 Cosmic microwave background radiation
The Cosmic Microwave Background Radiation is a form of electromagnetic radiation that fills the whole of the universe.
This radiation is regarded as the best available evidence of the Big Bang theory -- it gives a snapshot of the Universe when the temperature dropped enough to allow electrons and protons to form hydrogen atoms, thus making the universe transparent to radiation.
Probably still the most famous of these is the Cosmic Background Explorer (COBE) satellite that was flown in 1989-1996, which made the first detection of anisotropies (other than the dipole).
www.ebroadcast.com.au /lookup/encyclopedia/cm/CMB.html   (464 words)

  
 Cosmic microwave background radiation Summary
The cosmic microwave background was predicted by George Gamow, Ralph Alpher, and Robert Hermann in 1948.
The interpretation of the cosmic microwave background was a controversial issue in the 1960s with some proponents of the steady state theory arguing that the microwave background was the result of scattered starlight from distant galaxies.
The period after the emission of the cosmic microwave background and before the observation of the first stars is semi-humorously referred to by cosmologists as the dark age, and is a period which is under intense study by astronomers (See 21 centimeter radiation).
www.bookrags.com /Cosmic_microwave_background_radiation   (5849 words)

  
 Cosmic sound - curvature and the microwave background radiation
The photons that were set free in the transition from a cosmic plasma to stable atoms make up the cosmic microwave background radiation which is present everywhere in the cosmos.
The radiation is thermal - its spectrum depends only on a single parameter, the radiation temperature (further information about this type of radiation can be found in the spotlight text Heat that meets the eye).
When the first stable atoms formed, the sound waves in the cosmic plasma caused tiny fluctuations in the temperature of the cosmic microwave background: The temperatures of the radiation reaching us from different regions in the sky typically differ by some hundredth or tenth of a thousandth Kelvin (equivalently, degrees Celsius).
www.einstein-online.info /en/spotlights/cosmic_sound/index.html   (1368 words)

  
 The Astrophysics Spectator: The Cosmic Microwave Background   (Site not responding. Last check: 2007-10-07)
The radiation at this time behaved like radiation trapped within the interior of a star: the radiation stayed in thermal equilibrium with the matter, and so was characterized by a fl body spectrum.
The radiative processes are the same as found at the centers of stars: radiation scatters with free electrons (Compton scattering), and the emission and absorption of radiation as free electrons pass by ions (bremsstrahlung emission and absorption).
The microwave background is an important feature of the big bang theory of the universe, and its detection proved to be the most persuasive piece of evidence for the theory.
www.astrophysicsspectator.com /topics/cosmology/MicrowaveBackground.html   (780 words)

  
 Research at KICP: Cosmic Background Radiations
This radiation was produced at a specific epoch in the history of the Universe - when the matter had cooled enough that light could stream freely though the Universe without being scattered by electrons.
Since this radiation was emitted at a specific time in the history of the expansion of the Universe it carries with it the signatures of the structure of the Universe at that epoch.
The Cosmic Infrared Background Radiation (CIB) is the integrated light from all such dust in the line-of-sight and not from protogalaxies at a specific redshift (unlike the CMB radiation).
cfcp.uchicago.edu /research/cosmicradiation   (823 words)

  
 ipedia.com: Cosmic microwave background radiation Article   (Site not responding. Last check: 2007-10-07)
Cosmic microwave background radiation June 2001 The Cosmic Microwave Background Radiation is a form of electromagnetic radiation that fills the whole of the universe.
This radiation is regarded as the best available evidence of the Big Bang (BB) theory and its discovery in the mid-1960s marked the end of general interest for alternatives such as the steady state theory.
Of these experiments, the 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).
www.ipedia.com /cosmic_microwave_background_radiation.html   (1071 words)

  
 COSMIC MICROWAVE BACKGROUND RADIATION.
The CMBR monopole spectrum graph is supposedly the expanded flbody temperature plot of the early universe after it had evolved for 300,000 or 10 million years (the goal posts keep changing), at which time it had cooled to 4000 degrees K, being the temperature threshold where hydrogen was no longer ionized.
Background radiation curves can then be plotted within the parameters of, infinite background emissions of zero energy (1 x 0), and zero background emission in the present (0 x 1).
That represents a substantial velocity relative to the cosmic background.
members.optusnet.com.au /~maxkeon/cmbr.html   (1840 words)

  
 COBE - Cosmic Background Explorer
NASA's COBE (Cosmic Bakground Explorer) satellite was developed to measure the diffuxe infrared and cosmic microwave background radiation from the early Universe to the limits set by our astrophysical environment.
1992) has found anisotropies in the cosmic microwave background on all scales from the nominal beam size of 7-degrees up to the full sky at a typical level of one part in 100,000 to a few parts per million.
FIRAS has shown that the cosmic microwave background spectrum matches that of a flbody of temperature 2.726K with a precision of 0.03% of the peak intensity over a wavelength range 0.1 to 5 mm.
aether.lbl.gov /www/projects/cobe   (520 words)

  
 Scientific American: Ask the Experts: Astronomy: What is the cosmic microwave background radiation?
The Cosmic Microwave Background radiation, or CMB for short, is a faint glow of light that fills the universe, falling on Earth from every direction with nearly uniform intensity.
This residual radiation is critical to the study of cosmology because it bears on it the fossil imprint of those particles, a pattern of miniscule intensity variations from which we can decipher the vital statistics of the universe, like identifying a suspect from his fingerprint.
When this cosmic background light was released billions of years ago, it was as hot and bright as the surface of a star.
www.sciam.com /askexpert_question.cfm?chanID=sa007&articleID=00065CD0-F889-1F60-905980A84189EEDF   (623 words)

  
 Cosmology
The uniformity of the background radiation is evidence for the cosmological principle.
This background radiation is interpreted to be the relic of the early universe.
Notice that the background appears completely uniform at a temperature of 2.728 K. The colors for the temperatures range from blue for 2.724 K to red for 2.732 K. The double-lobe pattern shows the doppler effect from the motion of the Sun with respect to the background radiation.
www.astronomynotes.com /cosmolgy/s5.htm   (1289 words)

  
 IEEEVM: Cosmic Background Radiation
Gamow calculated the intensity of this remnant radiation to be equal to the radiation from a body kept at a temperature of approximately 3 °K (—270 °C, —454 °F).
At this point, radiation split from matter and was released in a flash at 3000 °K. These photons have since traveled some 15 billion years and account for the radiation bathing the universe.
As a result of the large-scale dissimilarity in the distribution of matter in the universe, the cosmological theories require that the intensity (and hence the “temperature”) of the cosmic microwave background radiation vary with direction in the sky.
www.ieee-virtual-museum.org /collection/event.php?id=3456993&lid=1   (830 words)

  
 Cosmic Microwave Background Radiation
Cosmic Microwave Background Radiation (CMBR) is a messenger from this soup.
Primer matter was immersed in radiation (gamma rays, X rays, light) and they were constantly in interaction with those particles, then the universe get cool enough as for forming the atoms, and the radiation didn't interact again.
Figure: Radiation chart from shortly after big Bang, x axis corresponds to the frequency of the radiation, and the vertical axis to the intensity.
library.thinkquest.org /C0114565/content.php?id=191   (366 words)

  
 The Cosmic Background Radiation
If the Earth moves with respect to the microwave background, it will be blue shifted to a higher effective temperature in the direction of the Earth's motion and red shifted to a lower effective temperature in the direction opposite the Earth's motion.
The cosmic background radiation (sometimes called the CBR), is the afterglow of the big bang, cooled to a faint whisper in the microwave spectrum by the expansion of the Universe for 15 billion years (which causes the radiation originally produced in the big bang to redshift to longer wavelengths).
As shown in the adjacent intensity map of the background radiation in different directions taken by the Differential Microwave Radiometer on NASA's COBE satellite, it is not completely uniform, though it is very nearly so (Ref).
csep10.phys.utk.edu /astr162/lect/cosmology/cbr.html   (660 words)

  
 Cosmic Microwave Background Radiation
In addition to this cosmic microwave background radiation, the early universe was filled with hot hydrogen gas with a density of about 1000 atoms per cubic centimeter (a teaspoon is roughly 3 cubic centimeters).
The behavior of cosmic microwave background photons moving through the early universe is analogous to the propagation of optical light through the Earth's atmosphere.
Cosmologists studying the cosmic microwave background radiation can look through much of the universe back to when it was opaque: a view back to 500,000 years after the Big Bang.
vista.lbl.gov /~barnett/universe.adventure/cbr.htm   (901 words)

  
 Frequency of the Cosmic Microwave Background
The Cosmic Microwave Background (CMB) is the isotropic, electromagnetic radiation which resulted from the explosion of the universe between 15 and 18 billion years ago.
Cosmic Microwave Background is the greatest evidence in support of the Big Bang theory.
Due to the constant expansion of the universe, the radiation had cooled to 2.73 K. The cmB is isotropic, meaning that it is uniform throughout the universe in all directions.
hypertextbook.com /facts/2004/HeatherFriedberg.shtml   (600 words)

  
 CMBR, Cosmic Microwave Background Radiation, Origin and Evolution - Bad Astronomy and Universe Today Forum   (Site not responding. Last check: 2007-10-07)
But in all of those cases the thermal background is an exceptional acident, with "thermal" being a special case of "background", which has to be contrived.
In current mainstream (big bang) cosmology, it is the cosmic infrared background which represents the light from the first generation of stars.
If you or Coldcreation are claiming that the measured background radiation is a result of "background starlight", well, clearly the existing stars and other bright objects are not ALL in thermal equilibrium with each other.
www.bautforum.com /showthread.php?t=51544   (4182 words)

  
 Temperature of the Cosmic Background Radiation
Going through different sources, I found the cosmic background radiataion varies from 2.7 K to 3 K. After further study, I believe the cosmic background radiation should be around 2.7 K because the texts that state this value give more accurate and detailed information than other texts.
All of my research sources agree that the cosmic background radiation must have been thermalized when the universe was denser and hotter than it is now.
According to Big Bang, the temperature of the microwave background increases linearly with redshift, a measure of the distance to faraway objects.
www.hypertextbook.com /facts/1997/SilinYang.shtml   (506 words)

  
 Radiation Technologies, Inc. Background and Qualifications
Radiation Technologies, Inc. (RTI) is a woman-owned small business that provides research, development and professional services to government, university, and industry customers.
Radiation Technologies specializes in design, fabrication and fielding of specialized systems for data acquisition where the application requirements are not well met by existing commercial systems.
Knowledge of radiation detection and measurement is coupled with an agility in design and allows us to understand the instrumentation needs and respond with a design which meets those needs.
www.radiationtechnologies.com /background.html   (522 words)

  
 SPACE.com -- About WMAP and the Cosmic Microwave Background
The cosmic microwave background provides a picture of the universe at a time prior to anything that can be seen with conventional telescopes that monitor visible light or even X-rays
The Microwave Anisotropy Probe (MAP) observatory, launched June 30, 2001, measures the microwave background's extremely tiny variations.
Scientists study the variations for clues about the size and geometry of the early universe, as well as the matter that was present when the microwave background was released.
www.space.com /scienceastronomy/map_mission_basics_030211.html   (916 words)

  
 Smoot Cosmology Group
NASA's COBE (Cosmic Background Explorer) satellite was developed to measure the diffuse infrared and cosmic microwave background radiation from the early Universe to the limits set by our astrophysical environment.
1992) has found anisotropies in the cosmic microwave background on all scales from the nominal beam size of 7-degrees up to the full sky at a typical level of one part in 100,000 to a few parts per million.
FIRAS has shown that the cosmic microwave background spectrum matches that of a flbody of temperature 2.726K with a precision of 0.03% of the peak intensity over a wavelength range 0.1 to 5 mm.
cosmos.lbl.gov /cobehome.html   (500 words)

  
 The Expanding Universe
The radiation that Penzias and Wilson discovered, called the Cosmic Microwave Background Radiation, convinced most astronomers that the Big Bang theory was correct.
After Penzias and Wilson found the Cosmic Microwave Background Radiation, astrophysicists began to study whether they could use its properties to study what the universe was like long ago.
These particles constantly collided with the photons that made up the background radiation, which then had a temperature of over 3000 C. Soon after, the Universe expanded enough, and thus the background radiation cooled enough, so that the electrons could combine with the nuclei to form atoms.
cas.sdss.org /dr4/en/astro/universe/universe.asp   (1911 words)

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