Matches in DBpedia 2014 for { <http://dbpedia.org/resource/Cosmic_microwave_background> ?p ?o. }
Showing items 1 to 44 of
44
with 100 items per page.
- Cosmic_microwave_background abstract "The cosmic microwave background (CMB) is the thermal radiation assumed to be left over from the "Big Bang" of cosmology. In older literature, the CMB is also variously known as cosmic microwave background radiation (CMBR) or "relic radiation." The CMB is a cosmic background radiation that is fundamental to observational cosmology because it is the oldest light in the universe, dating to the epoch of recombination. With a traditional optical telescope, the space between stars and galaxies (the background) is completely dark. However, a sufficiently sensitive radio telescope shows a faint background glow, almost exactly the same in all directions, that is not associated with any star, galaxy, or other object. This glow is strongest in the microwave region of the radio spectrum. The CMB's serendipitous discovery in 1964 by American radio astronomers Arno Penzias and Robert Wilson was the culmination of work initiated in the 1940s, and earned the discoverers the 1978 Nobel Prize.The CMB is a snapshot of the oldest light in our Universe, imprinted on the sky when the Universe was just 380,000 years old. It shows tiny temperature fluctuations that correspond to regions of slightly different densities, representing the seeds of all future structure: the stars and galaxies of today.The CMB is well explained as radiation left over from an early stage in the development of the universe, and its discovery is considered a landmark test of the Big Bang model of the universe. When the universe was young, before the formation of stars and planets, it was denser, much hotter, and filled with a uniform glow from a white-hot fog of hydrogen plasma. As the universe expanded, both the plasma and the radiation filling it grew cooler. When the universe cooled enough, protons and electrons combined to form neutral atoms. These atoms could no longer absorb the thermal radiation, and so the universe became transparent instead of being an opaque fog. Cosmologists refer to the time period when neutral atoms first formed as the recombination epoch, and the event shortly afterwards when photons started to travel freely through space rather than constantly being scattered by electrons and protons in plasma is referred to as photon decoupling. The photons that existed at the time of photon decoupling have been propagating ever since, though growing fainter and less energetic, since the expansion of space causes their wavelength to increase over time (and wavelength is inversely proportional to energy according to Planck's relation). This is the source of the alternative term relic radiation. The surface of last scattering refers to the set of points in space at the right distance from us so that we are now receiving photons originally emitted from those points at the time of photon decoupling.Precise measurements of the CMB are critical to cosmology, since any proposed model of the universe must explain this radiation. The CMB has a thermal black body spectrum at a temperature of 2.72548±0.00057 K. The spectral radiance dEν/dν peaks at 160.2 GHz, in the microwave range of frequencies. (Alternatively if spectral radiance is defined as dEλ/dλ then the peak wavelength is 1.063 mm.)The glow is very nearly uniform in all directions, but the tiny residual variations show a very specific pattern, the same as that expected of a fairly uniformly distributed hot gas that has expanded to the current size of the universe. In particular, the spectral radiance at different angles of observation in the sky contains small anisotropies, or irregularities, which vary with the size of the region examined. They have been measured in detail, and match what would be expected if small thermal variations, generated by quantum fluctuations of matter in a very tiny space, had expanded to the size of the observable universe we see today. This is a very active field of study, with scientists seeking both better data (for example, the Planck spacecraft) and better interpretations of the initial conditions of expansion. Although many different processes might produce the general form of a black body spectrum, no model other than the Big Bang has yet explained the fluctuations. As a result, most cosmologists consider the Big Bang model of the universe to be the best explanation for the CMB.The high degree of uniformity throughout the observable universe and its faint but measured anisotropy lend strong support for the Big Bang model in general and the ΛCDM model in particular. Moreover, the WMAP and BICEP experiments have observed coherence of these fluctuations on angular scales that are larger than the apparent cosmological horizon at recombination. Either such coherence is acausally fine-tuned, or cosmic inflation occurred.On 17 March 2014, astronomers from the California Institute of Technology, the Harvard-Smithsonian Center for Astrophysics, Stanford University, and the University of Minnesota announced their detection of signature patterns of polarized light in the CMB, attributed to gravitational waves in the early universe, which if confirmed would provide strong evidence of cosmic inflation and the Big Bang.".
- Cosmic_microwave_background thumbnail Cmbr.svg?width=300.
- Cosmic_microwave_background wikiPageExternalLink 51553_Planck_CMB_Mollweide_565.jpg.
- Cosmic_microwave_background wikiPageExternalLink thecmb.org.
- Cosmic_microwave_background wikiPageExternalLink the-big-bang-and-cosmic-microwave-background.
- Cosmic_microwave_background wikiPageExternalLink 735683main_pia16873-full_full.jpg.
- Cosmic_microwave_background wikiPageExternalLink theme3.py?level=3&index1=87807.
- Cosmic_microwave_background wikiPageID "7376".
- Cosmic_microwave_background wikiPageRevisionID "605840171".
- Cosmic_microwave_background subject Category:Astronomical_radio_sources.
- Cosmic_microwave_background subject Category:Cosmic_background_radiation.
- Cosmic_microwave_background subject Category:Physical_cosmology.
- Cosmic_microwave_background subject Category:Radio_astronomy.
- Cosmic_microwave_background comment "The cosmic microwave background (CMB) is the thermal radiation assumed to be left over from the "Big Bang" of cosmology. In older literature, the CMB is also variously known as cosmic microwave background radiation (CMBR) or "relic radiation." The CMB is a cosmic background radiation that is fundamental to observational cosmology because it is the oldest light in the universe, dating to the epoch of recombination.".
- Cosmic_microwave_background label "Cosmic microwave background".
- Cosmic_microwave_background label "Fond diffus cosmologique".
- Cosmic_microwave_background label "Hintergrundstrahlung".
- Cosmic_microwave_background label "Kosmische achtergrondstraling".
- Cosmic_microwave_background label "Mikrofalowe promieniowanie tła".
- Cosmic_microwave_background label "Radiación de fondo de microondas".
- Cosmic_microwave_background label "Radiazione cosmica di fondo".
- Cosmic_microwave_background label "Radiação cósmica de fundo em micro-ondas".
- Cosmic_microwave_background label "Реликтовое излучение".
- Cosmic_microwave_background label "إشعاع الخلفية الكونية الميكروي".
- Cosmic_microwave_background label "宇宙マイクロ波背景放射".
- Cosmic_microwave_background label "宇宙微波背景辐射".
- Cosmic_microwave_background sameAs Reliktní_záření.
- Cosmic_microwave_background sameAs Hintergrundstrahlung.
- Cosmic_microwave_background sameAs Ακτινοβολία_υποβάθρου.
- Cosmic_microwave_background sameAs Radiación_de_fondo_de_microondas.
- Cosmic_microwave_background sameAs Fond_diffus_cosmologique.
- Cosmic_microwave_background sameAs Radiasi_latar_belakang_gelombang_mikro_kosmis.
- Cosmic_microwave_background sameAs Radiazione_cosmica_di_fondo.
- Cosmic_microwave_background sameAs 宇宙マイクロ波背景放射.
- Cosmic_microwave_background sameAs 우주_배경_복사.
- Cosmic_microwave_background sameAs Kosmische_achtergrondstraling.
- Cosmic_microwave_background sameAs Mikrofalowe_promieniowanie_tła.
- Cosmic_microwave_background sameAs Radiação_cósmica_de_fundo_em_micro-ondas.
- Cosmic_microwave_background sameAs m.022sf.
- Cosmic_microwave_background sameAs Q15605.
- Cosmic_microwave_background sameAs Q15605.
- Cosmic_microwave_background wasDerivedFrom Cosmic_microwave_background?oldid=605840171.
- Cosmic_microwave_background depiction Cmbr.svg.
- Cosmic_microwave_background isPrimaryTopicOf Cosmic_microwave_background.