The cosmic microwave background ( CMB, CMBR ) is electromagnetic radiation as the remainder of the early stages of the universe in Big Bang cosmology. In older literature, CMB is also known as cosmic microwave cosmic background (CMBR) or "relational radiation". CMB is a vague cosmic background radiation that fills all the space that is an important source of data in the early universe as it is the oldest electromagnetic radiation in the universe, which dates from the era of recombination. With traditional optical telescopes, the space between stars and galaxies ( background ) is really dark. However, quite sensitive radio telescopes show faint background noise, or light, almost isotropic, unrelated to stars, galaxies, or other objects. This light is strongest in the microwave region of the radio spectrum. The unintentional discovery of the CMB in 1964 by the American radio astronomer Arno Penzias and Robert Wilson was the culmination of a work that began in the 1940s, and acquired the inventors of the 1978 Nobel Prize in Physics.
The invention of CMB is an important proof of the origin of the Big Bang of the universe. When the universe was young, before the formation of stars and planets, it was denser, much hotter, and filled with uniform light from the hot-white fog of hydrogen plasma. As the universe expands, both the plasma and the radiation that fill it become cooler. When the universe cools enough, protons and electrons combine to form neutral hydrogen atoms. In contrast to unincorporated protons and electrons, these newly recognizable atoms can not absorb heat radiation, so the universe becomes transparent rather than blurred. The cosmologist refers to the period of time when the neutral atom was first formed as an age of recombination, and the event immediately after that when photons began to travel freely through space rather than continuously scattered by electrons and protons in the plasma is called a photon decoupling. Photons that existed during photon decoupling have spread since then, though increasingly dim and less energetic, since space extensions cause their wavelengths to increase over time (and the wavelength is inversely proportional to the energy according to Planck relation). This is the source of the alternate term radiation relics . The last scattering surface refers to the set of dots in space at the exact distance from us so we now receive the photons originally emitted from the dots at the time of the decoupling photon.
Appropriate CMB measurements are essential for cosmology, as every proposed model of the universe should explain this radiation. CMB has a thermal black body spectrum at 2,725 48 Â ± span 0,000 57 K . Spectral Light dE ? /d? peak at 160.23 GHz, in the microwave frequency range, corresponding to the photon energy of about 6,626 ÃÆ'â € "10 -4 eV. Or, if the spectral rays are defined as dE ? /d?, Then the peak wavelength is 1.063 mm (282 GHz, 1.168 x 10 -3 eV photon). Light is very uniform in all directions, but small residual variations exhibit very specific patterns, just as expected from uniformly distributed hot gases that have expanded to the present size of the universe. In particular, the beam at various angles of observation in the sky contains a small anisotropy, or deviation, which varies with the size of the area examined. They have been measured in detail, and according to what is expected if the small thermal variations, generated by the quantum fluctuations of matter in very small spaces, have expanded to the size of the universe we see today. This is a very active field of study, with scientists looking for better data (eg, Planck spacecraft) and better interpretation of the initial conditions of expansion. Although many different processes can produce a common form of black body spectrum, no other model than the Big Bang has explained the fluctuations. Consequently, most cosmologists consider the Big Bang model in the universe as the best explanation for CMB.
High levels of uniformity across the observable universe and weak but measurable anisotropy provide strong support for the Big Bang model in general and the CDM model ("Lambda Cold Dark Matter") in particular. In addition, coherent fluctuations in angle scales are greater than the cosmological horizons seen in recombination. Either such coherence is aligned with acausally, or there is cosmic inflation.
Video Cosmic microwave background
Features
Radiation cosmic microwave background is the emission of black body heat energy coming from all parts of the sky. The radiation isotropic approximately one part in 100,000: average average root variation is only 18 Ã,ÂμK, after subtracting dipole anisotropy from Doppler background radiation shift. The latter is due to the strange speed of Earth relative to the cosmic residual frames that move as our planet moves at 371 km/sec towards the constellation Leo. The CMB dipole as well as the higher multipolar abnormalities have been measured, consistent with galaxy movement.
In the Big Bang model for the formation of the universe, inflation cosmology predicts that after about 10 -37 seconds, the newborn universe experiences an exponential growth that smooths most of the irregularities. The remaining irregularity is caused by quantum fluctuations in the inflaton field causing inflation events. Before the formation of stars and planets (after 10 -6 sec), the early universe was smaller, much hotter, and filled with uniform light from the hot white fog that interacted with plasma photons, electrons. , and baryon.
As the universe expands, adiabatic cooling causes the plasma energy density to decline until it becomes advantageous for the electrons to join the protons, forming a hydrogen atom. This recombination event occurs when the temperature is about 3000 Â ° K or when the universe is about 379,000 years old. Because photons do not interact with these electrically neutral atoms, the first begins to move freely through space, resulting in separation of matter and radiation.
The color temperature of the separated ensemble of photons has continued to decrease ever since; now down to 2.7260 Ã, Â ± 0.0013Ã, K , it will continue to decline as the universe expands. The intensity of the radiation also corresponds to the black body radiation at 2,726 K because the red-shifted body-black radiation is the same as the black body radiation at lower temperatures. According to the Big Bang model, the radiation from the sky that we measure today comes from the surface of the sphere called the last scattering surface . This is a collection of locations in the space where decoupling events are thought to have occurred and at some point in time so that photons from that distance have just reached the observer. Most of the radiation energy in the universe is in the cosmic microwave background, forming a fraction of about 6 ÃÆ' - 10 -5 of total density universe.
Two of Big Bang's greatest successes are his prediction of the almost perfect black body spectrum and the detailed prediction of his anisotropy in the cosmic microwave background. The CMB spectrum has become the most precisely measured black body spectrum in nature.
The energy density for CMB is 0.25 eV/cm 3 ( 4,005 ÃÆ' - 10 -14 Ã, J/m 3 ) or (400-500 foton/cm 3 ).
Maps Cosmic microwave background
History
The cosmic microwave background was first predicted in 1948 by Ralph Alpher and Robert Herman. Alpher and Herman were able to estimate cosmic microwave temperature temperatures to 5 Â ° K, although two years later they re-estimate at 28 ° C. This high estimate was due to the erroneous estimate of the Hubble constant by Alfred Behr, which could not be replicated and then abandoned for previous estimates. Although there are some previous estimates of room temperature, it suffers from two flaws. First, they measure the effective temperature space and do not indicate that the space is filled with Planck's thermal spectrum. Furthermore, they depend on our existence in a special place on the edge of the Milky Way galaxy and they do not suggest isotropic radiation. Estimates will produce very different predictions if the Earth happens to be elsewhere in the universe.
The 1948 results Alpher and Herman had discussed in many physics settings through about 1955, when both left the Applied Physics Laboratory at Johns Hopkins University. The mainstream astronomical community, however, was not interested in that moment by cosmology. The predictions of Alpher and Herman were rediscovered by Yakov Zel'dovich in the early 1960s, and independently predicted by Robert Dicke at the same time. The first publicized recognition of CMB radiation as a detectable phenomenon appeared in brief papers by US astrophysicist AG Doroshkevich and Igor Novikov, in the spring of 1964. In 1964, David Todd Wilkinson and Peter Roll, Dicke's colleagues at Princeton University, began building a radiometer Dicke to measure the cosmic microwave background. In 1964, Arno Penzias and Robert Woodrow Wilson at the Crawford Hill site in Bell Telephone Laboratories near the town of Holmdel, New Jersey have built a Dicke radiometer intended for use in radio astronomy and satellite communication experiments. On May 20, 1964, they made their first measurements clearly showing the existence of a microwave background, with their instruments having an excess of 4.2K antenna temperatures they could not calculate. After receiving a phone call from Crawford Hill, Dicke said "Boy, we've scooped up." The meeting between the Princeton and Crawford Hill groups determined that the antenna temperature was caused by a microwave background. Penzias and Wilson received the 1978 Nobel Prize in Physics for their discovery.
The interpretation of the cosmic microwave background is a controversial issue in the 1960s with some supporters of the steady state theory which suggest that microwaves are the result of the spreading starlight from distant galaxies. Using this model, and based on the study of the features of narrow line absorption in the spectrum of stars, astronomer Andrew McKellar wrote in 1941: "It can be calculated that the 'rotational temperature' of interstellar space is 2 Â ° C." However, during the 1970s a consensus was established that the cosmic microwave background was the rest of the big bang. This is largely because the new measurements in the frequency range indicate that the spectrum is the thermal spectrum, the black body, consequently the steady state model can not reproduce.
Harrison, Peebles, Yu, and Zel'dovich realized that the early universe had to have inhomogeneities at level -4 or 10 -5 . Rashid Sunyaev then calculated the observable traces that these inhomogeneities would exist on cosmic microwave backgrounds. The increasingly stringent limits on the anisotropy of the cosmic microwave background are determined by ground-based experiments during the 1980s. RELIKT-1, a Soviet-style cosmic microwave anisotropy experiment over the Prognoz 9 satellite (launched July 1, 1983) provides an upper limit on large-scale anisotropy. The NASA COBE mission clearly confirmed the primary anisotropy with the Differential Microwave Radiometer instrument, publishing their findings in 1992. The team received a Nobel Prize in physics for 2006 for this discovery.
Inspired by COBE results, a series of ground-based experiments and balloons measured the anisotropy of cosmic microwave backgrounds at smaller angular scales over the next decade. The main purpose of this experiment is to measure the scale of the first acoustic peak, which COBE does not have enough resolution to complete. This peak corresponds to the diversity of large-scale variations in the early universe created by gravitational instability, resulting in acoustic oscillations in plasma. The first peak in the anisotropy was tentatively detected by the Toco experiment and the results were confirmed by experiments BOOMERanG and MAXIMA. This measurement shows that the geometry of the universe is almost flat, not curved. They override cosmic strings as a major component of cosmic structure formation and suggest cosmic inflation is the correct theory for the formation of structures.
The second peak is tentatively detected by some experiments before it is detected definitively by the WMAP, which also detects a tentative third peak. In 2010, several experiments to improve polarization measurements and microwave backgrounds on a small angle scale are underway. These include Tie, WMAP, BOOMERanG, QUaD, Planck spacecraft, Atacama Cosmology Telescope, South Pole Telescope, and quiet telescope.
Relationship with Big Bang
Radiation of cosmic microwave backgrounds and the cosmological red distance relationship are together considered the best evidence available for the Big Bang theory. CMB measurements have made Big Bang's theory of inflation a Standard Cosmological Model. The invention of CMB in the mid-1960s limited interest in alternatives such as steady state theory.
The CMB essentially confirms the Big Bang theory. In the late 1940s Alpher and Herman reasoned that if there was a massive explosion, the expansion of the universe would stretch and cool the high-energy radiation from the early universe into the microwave region of the electromagnetic spectrum, and drop to a temperature of about 5Ã, Â ° K. with their estimates, but they have the right idea. They predict CMB. It took another 15 years for Penzias and Wilson to discover that the background of the microwaves was actually there.
CMB provides a snapshot of the universe when, according to standard cosmology, the temperature drops sufficiently to allow the electrons and protons to form hydrogen atoms, thus making the universe almost transparent to radiation because light is no longer dispersed from free electrons. When it originated about 380,000 years after the Big Bang - this time commonly known as "the last scattering time" or the recombination or discharge period - the temperature of the universe is around 3000Ã, Â °. This corresponds to an energy of about 0.26 eV, which is much smaller than the ionization energy of 13.6 eV of hydrogen.
Since decoupling, the temperature of background radiation has dropped by a factor of about 1,100 due to the expansion of the universe. When the universe expands, CMB photons change color to red, causing them to decrease energy. This radiation temperature remains inversely proportional to the parameters depicting the relative expansion of the universe over time, known as the long scale. The temperature T r of CMB as a redshift function, z , can be shown to be proportional to the CMB temperature as observed in the present (2,725 Â ° or 0.2348 meV):
- T r = 2,725 (1 z )
For details on the reason that radiation is the evidence of the Big Bang, see the Cosmic background radiation from Big Bang.
Primary anisotropy
Anisotropy, or directional dependence, of the cosmic microwave background is divided into two types: primary anisotropy, due to the effects that occur on the last and previous scattering surfaces; and secondary anisotropy, due to effects such as the interaction of background radiation with hot gas or gravitational potential, which occurs between the last scattering surface and the observer.
The anisotropic structure of the cosmic microwave background is principally determined by two effects: acoustic oscillation and diffusion damping (also called damping without crash or Silk damping). Acoustic oscillations arise because of conflicts in the photon-baryon plasma in the early universe. Photon pressure tends to remove anisotropy, while the gravitational pull of the baryons, moving at much slower speeds than light, makes them prone to collapse to form overdensity. These two effects compete to create acoustic oscillations, which provide the microscope background of the characteristic peak structure. The peak corresponds, roughly, to the resonance in which the photons separate when certain modes are at their peak amplitude.
The peak contains an interesting physical signature. The first peak angle scale determines the curvature of the universe (but not the topology of the universe). The next peak - the odd-peak ratio to even peak-determines the diminished baryon density. The third peak can be used to obtain information about dark matter densities.
The peak location also provides important information about the nature of the primordial density disorder. There are two basic density types called adiabatic and isocurvature . The general density disorder is a mixture of both, and different theories intended to explain the primordial density perturbation spectrum predict different mixtures.
- Adiabatic density perturbations
- In adiabatic density densities, the density of additional fractions of each particle type (baryon, photon...) is the same. That is, if in one place there is a density of 1% higher than baryon than average, then there is also a 1% higher density of photons (and a density of 1% higher in neutrinos) than on average. Cosmic inflation predicts that primordial disorders are adiabatic.
- Isocurvature density disorder
- In the isocurvature density disorder, the number (on various particle types) of the fractional additional density is zero. That is, a disorder where in some places there is 1% more energy in the baryon than on average, 1% more energy in photons than on average, and 2% less energy in neutrino than average average, will be purely an isocurvature disorder. Cosmic strings will produce a primordial isocurvature disorder.
The CMB spectrum can distinguish both because these two types of perturbation produce different peak locations. The density of the isocurvature density produces a series of peaks whose angular scales ( l peak values) are roughly in the ratio of 1: 3: 5:..., while adiabatic density disturbances produce peaks located at a 1: 2 ratio: 3:... Observations are consistent with a fully adiabatic primordial density disorder, providing major support for inflation, and setting aside many models of structure formation involving, for example, cosmic strings.
The attenuation of the collision is caused by two effects, when the primordial plasma treatment as a liquid begins to break down:
- free path means rising from photons as primordial plasmas becomes increasingly clarified in the evolving universe,
- the limited depth of the last scattering surface (LSS), which causes the average free path to rise rapidly during separation, even when some Compton scattering still occurs.
This effect contributes approximately equal to anisotropy suppression on a small scale and gives rise to the exponential dampening tail characteristics seen in very small angular anisotropy.
The depth of LSS refers to the fact that the separation of photons and baryons does not occur instantly, but instead requires a considerable fraction of the age of the universe up to that era. One method to measure how long this process uses is the photon visibility function (PVF). This function is defined so that, denoting PVF by P ( t ), it is likely that the last CMB photon is spread between the time t and < i> t dt is provided by P ( t ) dt
The maximum PVF (the time at which most CMB photons are last scattered) is known to be exact. The first year WMAP result places the time when P ( t ) has a maximum of 372,000 years. This is often regarded as the "time" in which CMB is formed. However, to find out how long it takes photons and baryons to separate, we need a PVF width size. The WMAP team found that PVF was more than half of its maximum value ("full width at half maximum", or FWHM) over an interval of 115,000 years. By this measure, the separation occurs about 115,000 years, and when it is finished, the universe is approximately 487,000 years old.
Anisotropy delay
Since CMB appears, it appears to have been modified by some subsequent physical process, which is collectively referred to as late anisotropy, or secondary anisotropy. When CMB photons become free to travel unimpeded, ordinary matter in the universe is mostly in the form of hydrogen atoms and neutral helium. However, current galaxy observations seem to indicate that most of the volume of intergalactic media (IGM) consists of ionised materials (since there are several absorption paths due to hydrogen atoms). This implies a period of reionization in which some matter of the universe is broken down into hydrogen ions.
CMB Photons are dispersed by free charges like unbound electrons in atoms. In an ionized universe, such charged particles have been liberated from neutral atoms with ionizing radiation (ultraviolet). Currently these free charges are at a fairly low density in most of the volumes of the universe so they do not affect CMB measurably. However, if IGM ionized at a very early time when the universe is still more dense, then there are two main effects on CMB:
- Small scale anisotropy is removed. (Just as when looking at objects through fog, the detail of the object seems blurry.)
- The physics of how photons scattered by free electrons (Thomson's scattering) induces polarization anisotropy at large angular scales. This wide angle polarization is correlated with wide-angle temperature interference.
Both of these effects have been observed by the WMAP spacecraft, providing evidence that the universe was ionized at a very early time, at a redshift of more than 17. The detailed proportions of this initial ionizing radiation remain a matter of scientific debate. This may include starlight from the first star populations (star population III), supernovas when the first stars reach their end of life, or ionizing radiation generated by the accretion of disks from large black holes.
The time after emission from the cosmic microwave background - and before the observation of the first stars - was semi-humorously referred to by cosmologists as the dark ages, and is a period under study by astronomers (see 21 centimeters). radiation).
Two other effects that occur between our reionization and our observations of cosmic microwave backgrounds, and which seem to cause anisotropy, are the effects of Sunyaev-Zel'dovich, in which high-energy electron clouds spread radiation, transfer some of its energy to CMB photons, and the effects of Sachs -Wolfe, which causes photons from the Cosmic Microwave Background to become a gravitational or blue redsition due to gravitational field changes.
Polarization
The cosmic microwave background is polarized at the level of some microkelvin. There are two types of polarization, called E-mode and B-mode. This is in analogy with electrostatics, where an electric field ( E -field) has a vanished arch and a magnetic field ( B -field) has a disappearing difference. E-mode appears naturally from Thomson scattering in heterogeneous plasma. Mode B is not generated by standard scalar type interference. Instead they can be made by two mechanisms: the first is with the E-mode gravity lens, which has been measured by the South Pole Telescope in 2013; the second comes from gravitational waves arising from cosmic inflation. Detecting B-mode is very difficult, especially since the level of foreground contamination is unknown, and the weak gravitational lens signal mixes a relatively strong E-mode signal with the B-mode signal.
E-mode
E-mode was first seen in 2002 by the Angular Scale Interferometer (DASI) Degree.
B-mode
Cosmologists predict two types of B-mode, which were first produced during cosmic inflation shortly after the big bang, and the second was generated by gravity lenses later on.
Primordial gravity waves
Primordial gravity waves are observed gravitational waves in cosmic microwave background polarization and have their origin in the early universe. Cosmic inflation models predict that such gravitational waves will emerge; thus, their detection supports the theory of inflation, and their strengths can confirm and exclude various inflation models. This is the result of three things: the expansion of space inflation itself, reheating after inflation, and the mixing of volatile liquid matter and radiation.
On March 17, 2014 it was announced that the BICEP2 instrument had detected the first type of B-mode, consistent with inflation and gravitational waves in the early universe at r = 0.20 0.07
-0.05 , which is the amount of power present in gravitational waves compared to the amount of power present in other scalar density disorders in the very early universe. If this were confirmed it would provide strong evidence of cosmic and Big Bang inflation, but on June 19, 2014, greatly reduced confidence in confirming the reported findings and on September 19, 2014 new results from the Planck experiment reported that the results of BICEP2 could be entirely associated with cosmic dust. Gravitational coating
The second type of B-mode was discovered in 2013 using the South Pole Telescope with the help of the Herschel Space Observatory. This discovery may help test the theory of the origin of the universe. Scientists use data from Planck's mission by the European Space Agency, to gain a better understanding of these waves.
In October 2014, the B-mode polarization measurements at 150 GHz were published by POLARBEAR experiments. Compared to BICEP2, POLARBEAR focuses on smaller sky areas and is less susceptible to dust effects. The team reported that the polarized B-mode POLARBEAR is cosmologically (and not just because of dust) at 97.2% confidence level.
Observation of microwave background
After the invention of CMB, hundreds of experimental cosmic microwave backgrounds have been performed to measure and characterize radiation signs. The most famous experiment was probably the NASA Cosmic Background Explorer (COBE) satellite that orbited in 1989-1996 and detected and quantified large-scale anisotropes at the limits of its detection ability. Inspired by early COBE results from highly isotropic and homogeneous backgrounds, a series of ball and balloon-based experiments quantified CMOS anisotropy at smaller angular scales over the next decade. The main purpose of this experiment is to measure the scale of the first acoustic peak angle, which COBE does not have sufficient resolution. This measurement is able to override cosmic strings as a leading theory of cosmic structure formation, and suggests cosmic inflation is the right theory. During the 1990s, the first peak was measured by increased sensitivity and in 2000, the BOOMERanG experiment reported that the highest power fluctuations occurred at a scale of about one degree. Along with other cosmological data, this result implies that the geometry of the universe is flat. A number of ground-based interferometers provide fluctuation measurements with higher accuracy over the next three years, including the Very Small Array, Interferometer Scale Datio (DASI), and Cosmic Background Imager (CBI). The tie makes the first detection of CMB and CBI polarization provides the first E-mode polarization spectrum with strong evidence that it is out of phase with the T-mode spectrum.
In June 2001, NASA launched the second CMB space mission, WMAP, to make much more precise measurements of large-scale anisotropes over the full sky. WMAP uses symmetric, fast multi-modulation scanning, fast switching radiometer to minimize non-sky signal interference. The first result of this mission, expressed in 2003, is the detailed measurement of angular power spectrum on a scale of less than one degree, which strictly limits cosmological parameters. The results are broadly consistent with expectations of cosmic inflation as well as other competing theories, and are available in detail at the NASA databank for Cosmic Microwave Background (CMB) (see link below). Although WMAP provides very accurate measurements of large-scale angular fluctuations in CMB (the structure is about as wide in the sky as the moon), it lacks angular resolution to measure the smaller scale fluctuations observed by earlier ground-based soils. interferometer.
The third space mission, ESA (European Space Agency) Planck Surveyor, was launched in May 2009 and conducts a more detailed investigation until it closes in October 2013. Planck uses a HEMT radiometer and bolometer technology and measures CMB on a smaller scale than WMAP. The detectors were tested on the Antarctic Viper telescope as an Arcmarute Cosmology Bolometer Array Receiver (ARB) experiment - which has produced the most precise measurements on a small angle scale to date - and in the Archaeops balloon telescope.
On March 21, 2013, a European-led research team behind the Planck cosmology investigation released an all-sky mission map (565x318 jpeg, 3600x1800 jpeg) from a cosmic microwave background. The map shows that the universe is slightly older than researchers thought. According to the map, subtle fluctuations in temperatures are imprinted in the deep sky when the cosmos is approximately 370 000 years. Traces reflect ripples that appear as early, in the existence of the universe, as the first billions of seconds. Apparently, these ripples give rise to a cluster of galaxy cosmos and vast dark matter. Based on 2013 data, the universe contains 4.9% ordinary matter, 26.8% dark matter and 68.3% dark energy. On 5 February 2015, new data released by Planck's mission, which states that the age of the universe is 13,799 Â ± 10.94> 0.021 billion years and the Hubble constant is measured to 67,74 Ã, Â ± 0.46Ã, (km/s)/Mpc .
Additional ground-based instruments such as the Antarctic Antarctic Telescope in the Antarctic and the proposed Semanggi Project, Atacama Cosmology Telescope and a quiet telescope in Chile will provide additional data not available from satellite observations, possibly including B-mode polarization.
Data reduction and analysis
Raw CMBR data, even from space vehicles such as WMAP or Planck, contain a foreground effect that completely obscures the fine-scale structure of the cosmic microwave background. The fine-scale structure is superimposed on CMBR raw data but is too small to see on the raw data scale. The most prominent of the foreground effect is the dipole anisotropy caused by the Sun's motion relative to the CMBR background. Dipole and other anisotropy due to the Earth's annual motion relative to the Sun and many microwave sources in the field of galaxies and elsewhere should be reduced to reveal very small variations that characterize the fine-grained CMBR background structure.
Detailed analysis of CMBR data to produce maps, spectrum of angular strength, and ultimately cosmological parameters are complicated problems that are computationally complex. Although calculating the power spectrum of the map is essentially a simple Fourier transform, outlining the sky map into a spherical harmonic, in practice it is difficult to take effect from noise and foreground sources into account. In particular, this foreground is dominated by galaxy emissions such as Bremsstrahlung, synchrotron, and dust flowing in microwaves; in practice, the galaxy should be removed, resulting in a CMB map that is not a full sky map. In addition, point sources such as galaxies and clusters are other foreground sources that must be removed so as not to damage the short-scale structure of the CMB power spectrum.
Limitations on many cosmological parameters can be obtained from their effect on the power spectrum, and the results are often calculated using Markov Chain Monte Carlo sampling technique.
CMBR dipole anisotropy
From the CMB data it is seen that the earth appears to move in 2a, km/s relative to the CMB reference frame (also called CMB break). frame, or reference frame where there is no movement through the CMB). The Local Group (the group of galaxies that includes the Milky Way galaxy) seems to be moving at 227 km/s i> = 276Ã, Â ° Ã, Â ± 3Ã, Â ° , b = 30Ã, Â ° Ã , Â ± 3 Â ° . This movement produces anisotropy data (CMB seems slightly warmer to the movement than the reverse direction). From a theoretical point of view, the existence of the CMB break framework destroys the invariant Lorentz even in empty spaces far from any galaxy. The standard interpretation of this temperature variation is a simple redshift of speed and a blue shift due to movement relative to CMB, but alternative cosmological models can account for some fractions of the distribution of dipole temperature observed in CMB.
Low multipoles and other anomalies
With increasingly precise data provided by WMAP, there are numerous claims that CMB shows anomalies, such as large scale anisotropies, anomaly alignments, and non-Gaussian distributions. The longest of these is the low multipole controversy l . Even on the COBE map, it was observed that quadrupole ( l = 2, spherical harmonics) has a low amplitude compared to Big Bang's prediction. In particular, quadrupole and octupole ( l = 3) modes seem to have unexplained parallels with each other and with both ecliptic planes and equinoxes, A number of groups have suggested that this could be a signature. new physics on the largest scale that can be observed; other groups suspect systematic errors in the data. Ultimately, because of the foreground and cosmic variance issues, the greatest mode can never be measured properly like a small angular corner mode. The analysis is done on two maps that have the foreground removed as far as possible: the "internal linear combination" map of the WMAP collaboration and similar maps prepared by Max Tegmark and others. Later analysis showed that this was the mode most susceptible to foreground contamination of synthetic, dust, and Bremsstrahlung emissions, and from experimental uncertainty in monopole and dipole. A full Bayesian analysis of the WMAP power spectrum showed that the Lambda-CDM cosmology quadrupole prediction was consistent with data at the 10% level and that the observed octupole was not remarkable. Carefully calculating the procedure used to remove the foreground from the full sky map further reduces the significance of alignment by ~ 5%. Recent observations with Planck telescopes, which are much more sensitive than WMAP and have larger angular resolutions, record the same anomaly, and instrumental faults (but not foreground contamination) seem to be ruled out. Incidentally is a possible explanation, WMAP's chief scientist Charles L. Bennett suggested coincidence and human psychology were involved, "I think there is little psychological effect; people want to find unusual things."
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