Astrophysics (Index)About

cosmic microwave background

(CMB, CMBR, CBR, MBR, cosmic microwave background radiation)
(microwave radiation coming from every direction)

Cosmic microwave background (CMB or CMBR, CBR, MBR) radiation is weak microwave electromagnetic radiation detectable in all directions, presumed to be a result of the Big Bang. It is quite uniform (showing just 0.04% wavelength-variation in its peak strength, throughout the celestial sphere) but the variation that exists (CMB anisotropies) is studied as a means of studying the early universe. The CMB was discovered by accident in 1964 by Arno Penzias and Robert Wilson, earning them the 1978 Nobel Prize, having been predicted in 1948 by Ralph Alpher and Robert Herman.

The photons date to the time of recombination, representing a "picture" of that time, at about redshift 1090. At that time, the universe became transparent as the combination of electrons and protons throughout space yielded neutral hydrogen, which is much less likely to scatter photons. The photons reaching us now have traveled directly from a spherical shell-shaped portion of the universe termed the surface of last scattering. The spectrum is basically a redshifted 3000 K black-body spectrum, appearing now as a 2.725 K black body spectrum.

Other types of radiation from every direction (cosmic background radiation) have also been found, though the phrase cosmic background radiation is sometimes used to mean specifically the CMB.

The phrase CMB foreground refers to microwave emission from nearer sources at the same frequencies. Such nearer sources are of interest to CMB researchers so they can be accounted for to work out an accurate picture of the CMB.


In planetary science, the initials CMB are also used to abbreviate an entirely different phrase: core-mantle boundary, i.e., the border of a planet's core.


(EMR,microwave,CBR,background,early universe,recombination)
Further reading:
http://en.wikipedia.org/wiki/CMB
WaveLFreqPhoton
Energy
  
1.1mm282.2GHz1.2meVcosmic microwave background
RedshiftParsecs
/Distance
Lightyears
/Lookback Years
  
10904.29Gpc13.98Glycosmic microwave background

Referenced by pages:
Atacama B-Mode Search (ABS)
ACBAR
Atacama Cosmology Telescope (ACT)
alternative cosmologies
anomalous microwave emission (AME)
Arcminute Microkelvin Imager (AMI)
angular power spectrum
anisotropy
ARCADE
Archeops
baryon acoustic oscillations (BAO)
BOOMERanG
C-BASS
Cosmic Background Imager (CBI)
cosmic background radiation (CBR)
CCAT-prime (CCAT-p)
cosmic infrared background (CIB)
CMB anisotropies
CMB lensing
CMB polarization
cosmic optical background (COB)
Cosmic Background Explorer (COBE)
cold spot
Compton scattering
computational astrophysics
COPSS
cosmological simulation
dark energy
dark matter
DASI
decoupling
destriping
DGP gravity
diffuse emission
diffusion damping
Dragone telescope
extragalactic background light (EBL)
epoch of reionization (EOR)
foreground subtraction
free streaming
Fsky (fsky)
Galactic Emission Mapping (GEM)
gravitational wave background (GWB)
gravitational-wave detector
GZK limit
HEALPix
inflation
initial fluctuations
initial fluctuation spectrum
intensity mapping
isotropy
LAMBDA
light cone
LiteBIRD
magnetic energy spectrum
MAXIMA
microwave
millimeter astronomy
maximum likelihood mapmaking
multipole expansion
non-Gaussian (NG)
N-point function
Planck
polarimetry
polarization
polarization modes
primordial gravitational waves
QMAP
QUIJOTE
Rayleigh scattering
recombination
relic
RELIKT-1
spectral energy distribution (SED)
Simons Observatory (SO)
spherical harmonics
spinning dust emission
South Pole Telescope (SPT)
surface brightness (SB)
surface of last scattering
Sachs-Wolfe effect (SWE)
Sunyaev-Zel'dovich Array (SZA)
Sunyaev-Zel'dovich effect (SZ effect)
thermal dust emission
Thomson optical depth (τT)
Thomson scattering
time-ordered data (TOD)
TopHat
topological defect
Very Small Array (VSA)
weak lensing (WL)
Wilkinson Microwave Anisotropy Probe (WMAP)

Index