Big Bang
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Big Bang

Timeline of the metric expansion of space, where space, including hypothetical non-observable portions of the universe, is represented at each time by the circular sections. On the left, the dramatic expansion occurs in the inflationary epoch; and at the center, the expansion accelerates (artist's concept; not to scale).

The Big Bang theory is a cosmological model for the observable universe[1][2][3] from the earliest known periods through its subsequent large-scale evolution.[4][5][6] The model describes how the universe expanded from a very high-density and high-temperature state,[7][8] and offers a comprehensive explanation for a broad range of phenomena, including the abundance of light elements, the cosmic microwave background (CMB), large-scale structure and Hubble's law (the farther away galaxies are, the faster they are moving away from Earth).[9] If the observed conditions are extrapolated backwards in time using the known laws of physics, the prediction is that just before a period of very high density there was a singularity which is typically associated with the Big Bang. Current knowledge is insufficient to determine if the singularity was primordial.

Since Georges Lemaître first noted in 1927 that an expanding universe could be traced back in time to an originating single point, scientists have built on his idea of cosmic expansion. The scientific community was once divided between supporters of two different theories, the Big Bang and the steady state theory, but a wide range of empirical evidence has strongly favored the Big Bang which is now universally accepted.[10] In 1929, from analysis of galactic redshifts, Edwin Hubble concluded that galaxies are drifting apart; this is important observational evidence for an expanding universe. In 1964, the cosmic microwave background radiation was discovered, which was crucial evidence in favor of the hot Big Bang model,[11] since that theory predicted the existence of background radiation throughout the universe before it was discovered.

The known physical laws of nature can be used to calculate the characteristics of the universe in detail back in time to an initial state of extreme density and temperature.[12] Detailed measurements of the expansion rate of the universe place the Big Bang at around 13.8 billion years ago, which is thus considered the age of the universe.[13] After its initial expansion, the universe cooled sufficiently to allow the formation of subatomic particles, and later atoms. Giant clouds of these primordial elements (mostly hydrogen, with some helium and lithium) later coalesced through gravity, eventually forming early stars and galaxies, the descendants of which are visible today. Astronomers also observe the gravitational effects of dark matter surrounding galaxies. Most of the matter in the universe seems to be in the form of dark matter, and the Big Bang theory and various observations indicate that it is not conventional baryonic matter (atoms). It is still not known exactly what dark matter is. More recently, measurements of the redshifts of supernovae indicate that the expansion of the universe is accelerating, an observation attributed to dark energy's existence.[14]


External Timeline A graphical timeline is available at
Graphical timeline of the Big Bang

In 1922, Russian mathematician Alexander Friedmann[15] proposed on theoretical grounds that the universe is expanding, which was rederived independently and observationally confirmed soon afterwards by Belgian astronomer and Catholic priest Georges Lemaître in 1927[16][17][18] Lemaître also proposed what became known as the "Big Bang theory" of the creation of the universe, originally calling it the "hypothesis of the primeval atom".:[19] in his paper Annales de la Société Scientifique de Bruxelles (Annals of the Scientific Society of Brussels) under the title "Un Univers homogène de masse constante et de rayon croissant rendant compte de la vitesse radiale des nébuleuses extragalactiques" ("A homogeneous Universe of constant mass and growing radius accounting for the radial velocity of extragalactic nebulae"),[20] he presented his new idea that the universe is expanding and provided the first observational estimation of what is known as the Hubble constant.[21] What later will be known as the "Big Bang theory" of the origin of the universe, he called his "hypothesis of the primeval atom" or the "Cosmic Egg".[22]





Nonetheless, in November 2019, Jim Peebles, awarded the 2019 Nobel Prize in Physics for his theoretical discoveries in physical cosmology.[24] noted, in his award presentation, that he does not support the Big Bang Theory, due to the lack of concrete supporting evidence, and stated, "It's very unfortunate that one thinks of the beginning whereas in fact, we have no good theory of such a thing as the beginning."[25]



Extrapolation of the expansion of the universe backwards in time using general relativity yields an infinite density and temperature at a finite time in the past.[26] This singularity indicates that general relativity is not an adequate description of the laws of physics in this regime. Models based on general relativity alone can not extrapolate toward the singularity beyond the end of the Planck epoch.

This primordial singularity is itself sometimes called "the Big Bang",[27] but the term can also refer to a more generic early hot, dense phase[28][notes 1] of the universe. In either case, "the Big Bang" as an event is also colloquially referred to as the "birth" of our universe since it represents the point in history where the universe can be verified to have entered into a regime where the laws of physics as we understand them (specifically general relativity and the standard model of particle physics) work. Based on measurements of the expansion using Type Ia supernovae and measurements of temperature fluctuations in the cosmic microwave background, the time that has passed since that event -- otherwise known as the "age of the universe" -- is 13.799 ± 0.021 billion years.[29] The agreement of independent measurements of this age supports the ?CDM model that describes in detail the characteristics of the universe.

Despite being extremely dense at this time--far denser than is usually required to form a black hole--the universe did not re-collapse into a black hole. This may be explained by considering that commonly-used calculations and limits for gravitational collapse are usually based upon objects of relatively constant size, such as stars, and do not apply to rapidly expanding space such as the Big Bang.

Inflation and baryogenesis

The earliest phases of the Big Bang are subject to much speculation. In the most common models the universe was filled homogeneously and isotropically with a very high energy density and huge temperatures and pressures and was very rapidly expanding and cooling. Approximately 10-37 seconds into the expansion, a phase transition caused a cosmic inflation, during which the universe grew exponentially and during which time density fluctuations that occurred because of the uncertainty principle were amplified into the seeds that would later form the large-scale structure of the universe.[30] After inflation stopped, reheating occurred until the universe obtained the temperatures required for the production of a quark-gluon plasma as well as all other elementary particles.[31] Temperatures were so high that the random motions of particles were at relativistic speeds, and particle-antiparticle pairs of all kinds were being continuously created and destroyed in collisions.[7] At some point, an unknown reaction called baryogenesis violated the conservation of baryon number, leading to a very small excess of quarks and leptons over antiquarks and antileptons--of the order of one part in 30 million. This resulted in the predominance of matter over antimatter in the present universe.[32]



The universe continued to decrease in density and fall in temperature, hence the typical energy of each particle was decreasing. Symmetry breaking phase transitions put the fundamental forces of physics and the parameters of elementary particles into their present form.[33] After about 10-11 seconds, the picture becomes less speculative, since particle energies drop to values that can be attained in particle accelerators. At about 10-6 seconds, quarks and gluons combined to form baryons such as protons and neutrons. The small excess of quarks over antiquarks led to a small excess of baryons over antibaryons. The temperature was now no longer high enough to create new proton-antiproton pairs (similarly for neutrons-antineutrons), so a mass annihilation immediately followed, leaving just one in 1010 of the original protons and neutrons, and none of their antiparticles. A similar process happened at about 1 second for electrons and positrons. After these annihilations, the remaining protons, neutrons and electrons were no longer moving relativistically and the energy density of the universe was dominated by photons (with a minor contribution from neutrinos).

A few minutes into the expansion, when the temperature was about a billion (one thousand million) kelvin and the density was about that of air, neutrons combined with protons to form the universe's deuterium and helium nuclei in a process called Big Bang nucleosynthesis.[34] Most protons remained uncombined as hydrogen nuclei.[35]

As the universe cooled, the rest mass energy density of matter came to gravitationally dominate that of the photon radiation. After about 379,000 years, the electrons and nuclei combined into atoms (mostly hydrogen); hence the radiation decoupled from matter and continued through space largely unimpeded. This relic radiation is known as the cosmic microwave background radiation.[35] The chemistry of life may have begun shortly after the Big Bang, 13.8 billion years ago, during a habitable epoch when the universe was only 10-17 million years old.[36][37][38]

Structure formation


Over a long period of time, the slightly denser regions of the nearly uniformly distributed matter gravitationally attracted nearby matter and thus grew even denser, forming gas clouds, stars, galaxies, and the other astronomical structures observable today.[7] The details of this process depend on the amount and type of matter in the universe. The four possible types of matter are known as cold dark matter, warm dark matter, hot dark matter, and baryonic matter. The best measurements available, from Wilkinson Microwave Anisotropy Probe (WMAP), show that the data is well-fit by a Lambda-CDM model in which dark matter is assumed to be cold (warm dark matter is ruled out by early reionization),[40] and is estimated to make up about 23% of the matter/energy of the universe, while baryonic matter makes up about 4.6%.[41] In an "extended model" which includes hot dark matter in the form of neutrinos, then if the "physical baryon density" is estimated at about 0.023 (this is different from the 'baryon density' expressed as a fraction of the total matter/energy density, which as noted above is about 0.046), and the corresponding cold dark matter density is about 0.11, the corresponding neutrino density is estimated to be less than 0.0062.[41]

Cosmic acceleration



All of this cosmic evolution after the inflationary epoch can be rigorously described and modeled by the ?CDM model of cosmology, which uses the independent frameworks of quantum mechanics and Einstein's General Relativity. There is no well-supported model describing the action prior to 10-15 seconds or so. Apparently a new unified theory of quantum gravitation is needed to break this barrier. Understanding this earliest of eras in the history of the universe is currently one of the greatest unsolved problems in physics.

Features of the model


These ideas were initially taken as postulates, but today there are efforts to test each of them. For example, the first assumption has been tested by observations showing that largest possible deviation of the fine structure constant over much of the age of the universe is of order 10-5.[42] Also, general relativity has passed stringent tests on the scale of the Solar System and binary stars.[notes 2]

If the large-scale universe appears isotropic as viewed from Earth, the cosmological principle can be derived from the simpler Copernican principle, which states that there is no preferred (or special) observer or vantage point. To this end, the cosmological principle has been confirmed to a level of 10-5 via observations of the CMB. The universe has been measured to be homogeneous on the largest scales at the 10% level.[43]

Expansion of space

General relativity describes spacetime by a metric, which determines the distances that separate nearby points. The points, which can be galaxies, stars, or other objects, are themselves specified using a coordinate chart or "grid" that is laid down over all spacetime. The cosmological principle implies that the metric should be homogeneous and isotropic on large scales, which uniquely singles out the Friedmann-Lemaître-Robertson-Walker metric (FLRW metric). This metric contains a scale factor, which describes how the size of the universe changes with time. This enables a convenient choice of a coordinate system to be made, called comoving coordinates. In this coordinate system, the grid expands along with the universe, and objects that are moving only because of the expansion of the universe, remain at fixed points on the grid. While their coordinate distance (comoving distance) remains constant, the physical distance between two such co-moving points expands proportionally with the scale factor of the universe.[44]

The Big Bang is not an explosion of matter moving outward to fill an empty universe. Instead, space itself expands with time everywhere and increases the physical distance between two comoving points. In other words, the Big Bang is not an explosion in space, but rather an expansion of space.[7] Because the FLRW metric assumes a uniform distribution of mass and energy, it applies to our universe only on large scales--local concentrations of matter such as our galaxy are gravitationally bound and as such do not experience the large-scale expansion of space.[45]






English astronomer Fred Hoyle is credited with coining the term "Big Bang" during a 1949 BBC radio broadcast, saying: "These theories were based on the hypothesis that all the matter in the universe was created in one big bang at a particular time in the remote past."[47]

It is popularly reported that Hoyle, who favored an alternative "steady state" cosmological model, intended this to be pejorative,[48] but Hoyle explicitly denied this and said it was just a striking image meant to highlight the difference between the two models.[49][50][51]:129


XDF size compared to the size of the Moon (XDF is the small box to the left of, and nearly below, the Moon) - several thousand galaxies, each consisting of billions of stars, are in this small view.
XDF (2012) view - each light speck is a galaxy - some of these are as old as 13.2 billion years[52] - the universe is estimated to contain 200 billion galaxies.

The Big Bang theory developed from observations of the structure of the universe and from theoretical considerations. In 1912, Vesto Slipher measured the first Doppler shift of a "spiral nebula" (spiral nebula is the obsolete term for spiral galaxies), and soon discovered that almost all such nebulae were receding from Earth. He did not grasp the cosmological implications of this fact, and indeed at the time it was highly controversial whether or not these nebulae were "island universes" outside our Milky Way.[53][54] Ten years later, Alexander Friedmann, a Russian cosmologist and mathematician, derived the Friedmann equations from Albert Einstein's equations of general relativity, showing that the universe might be expanding in contrast to the static universe model advocated by Einstein at that time.[55] In 1924 Edwin Hubble's measurement of the great distance to the nearest spiral nebulae showed that these systems were indeed other galaxies. Independently deriving Friedmann's equations in 1927, Georges Lemaître, a Belgian physicist, proposed that the inferred recession of the nebulae was due to the expansion of the universe.[56]


Starting in 1924, Hubble painstakingly developed a series of distance indicators, the forerunner of the cosmic distance ladder, using the 100-inch (2.5 m) Hooker telescope at Mount Wilson Observatory. This allowed him to estimate distances to galaxies whose redshifts had already been measured, mostly by Slipher. In 1929 Hubble discovered a correlation between distance and recession velocity--now known as Hubble's law.[23][58] Lemaître had already shown that this was expected, given the cosmological principle.[14]

In the 1920s and 1930s almost every major cosmologist preferred an eternal steady state universe, and several complained that the beginning of time implied by the Big Bang imported religious concepts into physics; this objection was later repeated by supporters of the steady state theory.[59] This perception was enhanced by the fact that the originator of the Big Bang theory, Georges Lemaître, was a Roman Catholic priest.[60]Arthur Eddington agreed with Aristotle that the universe did not have a beginning in time, viz., that matter is eternal. A beginning in time was "repugnant" to him.[61][62] Lemaître, however, thought that


During the 1930s other ideas were proposed as non-standard cosmologies to explain Hubble's observations, including the Milne model,[64] the oscillatory universe (originally suggested by Friedmann, but advocated by Albert Einstein and Richard Tolman)[65] and Fritz Zwicky's tired light hypothesis.[66]

After World War II, two distinct possibilities emerged. One was Fred Hoyle's steady state model, whereby new matter would be created as the universe seemed to expand. In this model the universe is roughly the same at any point in time.[67] The other was Lemaître's Big Bang theory, advocated and developed by George Gamow, who introduced Big Bang nucleosynthesis (BBN)[68] and whose associates, Ralph Alpher and Robert Herman, predicted the CMB.[69] Ironically, it was Hoyle who coined the phrase that came to be applied to Lemaître's theory, referring to it as "this big bang idea" during a BBC Radio broadcast in March 1949.[51][notes 3] For a while, support was split between these two theories. Eventually, the observational evidence, most notably from radio source counts, began to favor Big Bang over Steady State. The discovery and confirmation of the CMB in 1964 secured the Big Bang as the best theory of the origin and evolution of the universe.[71] Much of the current work in cosmology includes understanding how galaxies form in the context of the Big Bang, understanding the physics of the universe at earlier and earlier times, and reconciling observations with the basic theory.

In 1968 and 1970 Roger Penrose, Stephen Hawking, and George F. R. Ellis published papers where they showed that mathematical singularities were an inevitable initial condition of general relativistic models of the Big Bang.[72][73] Then, from the 1970s to the 1990s, cosmologists worked on characterizing the features of the Big Bang universe and resolving outstanding problems. In 1981, Alan Guth made a breakthrough in theoretical work on resolving certain outstanding theoretical problems in the Big Bang theory with the introduction of an epoch of rapid expansion in the early universe he called "inflation".[74] Meanwhile, during these decades, two questions in observational cosmology that generated much discussion and disagreement were over the precise values of the Hubble Constant[75] and the matter-density of the universe (before the discovery of dark energy, thought to be the key predictor for the eventual fate of the universe).[76]


Significant progress in Big Bang cosmology has been made since the late 1990s as a result of advances in telescope technology as well as the analysis of data from satellites such as COBE,[78] the Hubble Space Telescope and WMAP.[79] Cosmologists now have fairly precise and accurate measurements of many of the parameters of the Big Bang model, and have made the unexpected discovery that the expansion of the universe appears to be accelerating.

Observational evidence


Lawrence Krauss[80]


Precise modern models of the Big Bang appeal to various exotic physical phenomena that have not been observed in terrestrial laboratory experiments or incorporated into the Standard Model of particle physics. Of these features, dark matter is currently subjected to the most active laboratory investigations.[83] Remaining issues include the cuspy halo problem and the dwarf galaxy problem of cold dark matter. Dark energy is also an area of intense interest for scientists, but it is not clear whether direct detection of dark energy will be possible.[84]Inflation and baryogenesis remain more speculative features of current Big Bang models. Viable, quantitative explanations for such phenomena are still being sought. These are currently unsolved problems in physics.

Hubble's law and the expansion of space


Hubble's law has two possible explanations. Either we are at the center of an explosion of galaxies--which is untenable given the Copernican principle--or the universe is uniformly expanding everywhere. This universal expansion was predicted from general relativity by Alexander Friedmann in 1922[55] and Georges Lemaître in 1927,[56] well before Hubble made his 1929 analysis and observations, and it remains the cornerstone of the Big Bang theory as developed by Friedmann, Lemaître, Robertson, and Walker.

The theory requires the relation to hold at all times, where is the comoving distance, v is the recessional velocity, and , , and vary as the universe expands (hence we write to denote the present-day Hubble "constant"). For distances much smaller than the size of the observable universe, the Hubble redshift can be thought of as the Doppler shift corresponding to the recession velocity . However, the redshift is not a true Doppler shift, but rather the result of the expansion of the universe between the time the light was emitted and the time that it was detected.[85]


Measurements of the effects of the cosmic microwave background radiation on the dynamics of distant astrophysical systems in 2000 proved the Copernican principle, that, on a cosmological scale, the Earth is not in a central position.[86] Radiation from the Big Bang was demonstrably warmer at earlier times throughout the universe. Uniform cooling of the CMB over billions of years is explainable only if the universe is experiencing a metric expansion, and excludes the possibility that we are near the unique center of an explosion.

Cosmic microwave background radiation

The cosmic microwave background spectrum measured by the FIRAS instrument on the COBE satellite is the most-precisely measured black body spectrum in nature.[87] The data points and error bars on this graph are obscured by the theoretical curve.


The surface of last scattering corresponding to emission of the CMB occurs shortly after recombination, the epoch when neutral hydrogen becomes stable. Prior to this, the universe comprised a hot dense photon-baryon plasma sea where photons were quickly scattered from free charged particles. Peaking at around ,[40] the mean free path for a photon becomes long enough to reach the present day and the universe becomes transparent.

9 year WMAP image of the cosmic microwave background radiation (2012).[88][89] The radiation is isotropic to roughly one part in 100,000.[90]

In 1989, NASA launched the Cosmic Background Explorer satellite (COBE), which made two major advances: in 1990, high-precision spectrum measurements showed that the CMB frequency spectrum is an almost perfect blackbody with no deviations at a level of 1 part in 104, and measured a residual temperature of 2.726 K (more recent measurements have revised this figure down slightly to 2.7255 K); then in 1992, further COBE measurements discovered tiny fluctuations (anisotropies) in the CMB temperature across the sky, at a level of about one part in 105.[78]John C. Mather and George Smoot were awarded the 2006 Nobel Prize in Physics for their leadership in these results.

During the following decade, CMB anisotropies were further investigated by a large number of ground-based and balloon experiments. In 2000-2001 several experiments, most notably BOOMERanG, found the shape of the universe to be spatially almost flat by measuring the typical angular size (the size on the sky) of the anisotropies.[91][92][93]

In early 2003, the first results of the Wilkinson Microwave Anisotropy Probe (WMAP) were released, yielding what were at the time the most accurate values for some of the cosmological parameters. The results disproved several specific cosmic inflation models, but are consistent with the inflation theory in general.[79] The Planck space probe was launched in May 2009. Other ground and balloon based cosmic microwave background experiments are ongoing.

Abundance of primordial elements

Using the Big Bang model it is possible to calculate the concentration of helium-4, helium-3, deuterium, and lithium-7 in the universe as ratios to the amount of ordinary hydrogen.[34] The relative abundances depend on a single parameter, the ratio of photons to baryons. This value can be calculated independently from the detailed structure of CMB fluctuations. The ratios predicted (by mass, not by number) are about 0.25 for , about 10-3 for , about 10-4 for and about 10-9 for .[34]

The measured abundances all agree at least roughly with those predicted from a single value of the baryon-to-photon ratio. The agreement is excellent for deuterium, close but formally discrepant for , and off by a factor of two for ; in the latter two cases there are substantial systematic uncertainties. Nonetheless, the general consistency with abundances predicted by Big Bang nucleosynthesis is strong evidence for the Big Bang, as the theory is the only known explanation for the relative abundances of light elements, and it is virtually impossible to "tune" the Big Bang to produce much more or less than 20-30% helium.[94] Indeed, there is no obvious reason outside of the Big Bang that, for example, the young universe (i.e., before star formation, as determined by studying matter supposedly free of stellar nucleosynthesis products) should have more helium than deuterium or more deuterium than , and in constant ratios, too.[95]:182-185

Galactic evolution and distribution



Primordial gas clouds

Focal plane of BICEP2 telescope under a microscope - used to search for polarization in the CMB.[98][99][100][101]

In 2011, astronomers found what they believe to be pristine clouds of primordial gas by analyzing absorption lines in the spectra of distant quasars. Before this discovery, all other astronomical objects have been observed to contain heavy elements that are formed in stars. These two clouds of gas contain no elements heavier than hydrogen and deuterium.[102][103] Since the clouds of gas have no heavy elements, they likely formed in the first few minutes after the Big Bang, during Big Bang nucleosynthesis.

Other lines of evidence


The prediction that the CMB temperature was higher in the past has been experimentally supported by observations of very low temperature absorption lines in gas clouds at high redshift.[105] This prediction also implies that the amplitude of the Sunyaev-Zel'dovich effect in clusters of galaxies does not depend directly on redshift. Observations have found this to be roughly true, but this effect depends on cluster properties that do change with cosmic time, making precise measurements difficult.[106][107]

Future observations

Future gravitational waves observatories might be able to detect primordial gravitational waves, relics of the early universe, up to less than a second after the Big Bang.[108][109]

Problems and related issues in physics


Baryon asymmetry

It is not yet understood why the universe has more matter than antimatter.[114] It is generally assumed that when the universe was young and very hot it was in statistical equilibrium and contained equal numbers of baryons and antibaryons. However, observations suggest that the universe, including its most distant parts, is made almost entirely of matter. A process called baryogenesis was hypothesized to account for the asymmetry. For baryogenesis to occur, the Sakharov conditions must be satisfied. These require that baryon number is not conserved, that C-symmetry and CP-symmetry are violated and that the universe depart from thermodynamic equilibrium.[115] All these conditions occur in the Standard Model, but the effects are not strong enough to explain the present baryon asymmetry.

Dark energy




The dark energy component of the universe has been explained by theorists using a variety of competing theories including Einstein's cosmological constant but also extending to more exotic forms of quintessence or other modified gravity schemes.[116] A cosmological constant problem, sometimes called the "most embarrassing problem in physics", results from the apparent discrepancy between the measured energy density of dark energy, and the one naively predicted from Planck units.[117]

Dark matter




Additionally, there are outstanding problems associated with the currently favored cold dark matter model which include the dwarf galaxy problem[120] and the cuspy halo problem.[121] Alternative theories have been proposed that do not require a large amount of undetected matter, but instead modify the laws of gravity established by Newton and Einstein; yet no alternative theory has been as successful as the cold dark matter proposal in explaining all extant observations.[122]

Horizon problem

The horizon problem results from the premise that information cannot travel faster than light. In a universe of finite age this sets a limit--the particle horizon--on the separation of any two regions of space that are in causal contact.[123] The observed isotropy of the CMB is problematic in this regard: if the universe had been dominated by radiation or matter at all times up to the epoch of last scattering, the particle horizon at that time would correspond to about 2 degrees on the sky. There would then be no mechanism to cause wider regions to have the same temperature.[95]:191-202


Heisenberg's uncertainty principle predicts that during the inflationary phase there would be quantum thermal fluctuations, which would be magnified to cosmic scale. These fluctuations serve as the seeds of all current structure in the universe.[95]:207 Inflation predicts that the primordial fluctuations are nearly scale invariant and Gaussian, which has been accurately confirmed by measurements of the CMB.[124]:sec 6

If inflation occurred, exponential expansion would push large regions of space well beyond our observable horizon.[30]:180-186


Magnetic monopoles


Flatness problem


The flatness problem (also known as the oldness problem) is an observational problem associated with a Friedmann-Lemaître-Robertson-Walker metric (FLRW).[123] The universe may have positive, negative, or zero spatial curvature depending on its total energy density. Curvature is negative if its density is less than the critical density; positive if greater; and zero at the critical density, in which case space is said to be flat.

The problem is that any small departure from the critical density grows with time, and yet the universe today remains very close to flat.[notes 4] Given that a natural timescale for departure from flatness might be the Planck time, 10-43 seconds,[7] the fact that the universe has reached neither a heat death nor a Big Crunch after billions of years requires an explanation. For instance, even at the relatively late age of a few minutes (the time of nucleosynthesis), the density of the universe must have been within one part in 1014 of its critical value, or it would not exist as it does today.[126]

Ultimate fate of the universe


Alternatively, if the density in the universe were equal to or below the critical density, the expansion would slow down but never stop. Star formation would cease with the consumption of interstellar gas in each galaxy; stars would burn out, leaving white dwarfs, neutron stars, and black holes. Very gradually, collisions between these would result in mass accumulating into larger and larger black holes. The average temperature of the universe would asymptotically approach absolute zero--a Big Freeze.[127] Moreover, if the proton were unstable, then baryonic matter would disappear, leaving only radiation and black holes. Eventually, black holes would evaporate by emitting Hawking radiation. The entropy of the universe would increase to the point where no organized form of energy could be extracted from it, a scenario known as heat death.[128]



The following is a partial list of misconceptions about the Big Bang model:

The Big Bang as the origin of the universe: One of the common misconceptions about the Big Bang model is that it fully explains the origin of the universe. However, the Big Bang model does not describe how energy, time, and space was caused, but rather it describes the emergence of the present universe from an ultra-dense and high-temperature initial state.[130]

The Big Bang was "small": It is misleading to visualize the Big Bang by comparing its size to everyday objects. When the size of the universe at Big Bang is described, it refers to the size of the observable universe, and not the entire universe.[131]

Hubble's law violates the special theory of relativity: Hubble's law predicts that galaxies that are beyond Hubble distance recede faster than the speed of light. However, special relativity does not apply beyond motion through space. Hubble's law describes velocity that results from expansion of space, rather than through space.[131]

Doppler redshift vs cosmological redshift: Astronomers often refer to the cosmological redshift as a Doppler shift which can lead to a misconception.[131] Although similar, the cosmological redshift is not identical to the classically derived Doppler redshift because most elementary derivations of the Doppler redshift do not accommodate the expansion of space. Accurate derivation of the cosmological redshift requires the use of general relativity, and while a treatment using simpler Doppler effect arguments gives nearly identical results for nearby galaxies, interpreting the redshift of more distant galaxies as due to the simplest Doppler redshift treatments can cause confusion.[131]

Beyond the Big Bang

The Big Bang explains the evolution of the universe from a density and temperature that is well-beyond humanity's capability to replicate, so extrapolations to most extreme conditions and earliest times are necessarily more speculative. Georges Lemaître called this initial state the "primeval atom" while George Gamow called the material "ylem". How the initial state of the universe originated is still an open question, but the Big Bang model does constrain some of its characteristics. For example, observations indicate the universe is consistent with being flat which implies a balance between gravitational potential energy and other forms requiring no additional energy to be created,[132][133] while quantum fluctuations in the early universe can provide the circumstances for dense regions of matter (such as superclusters) to form. Ultimately, the Big Bang theory, built upon the equations of classical general relativity, indicates a singularity at the origin of cosmic time, and such an infinite energy density may be a physical impossibility. In any case, the physical theories of general relativity and quantum mechanics as currently realized are not applicable before the Planck Epoch, and correcting this will require the development of a correct treatment of quantum gravity.[134] Certain quantum gravity treatments, such as the Wheeler-DeWitt equation, imply that time itself could be an emergent property.[135] As such, physics may conclude that time did not exist before the Big Bang so there might be no beginning or before.[136][137]

While it is not known what could have preceded the hot dense state of the early universe or how and why it originated, or even whether such questions are sensible, speculation abounds as the subject of "cosmogony".

Some speculative proposals in this regard, each of which entails untested hypotheses, are:

  • Models including the Hartle-Hawking no-boundary condition, in which the whole of space-time is finite; the Big Bang does represent the limit of time but without any singularity.[138]

Proposals in the last two categories see the Big Bang as an event in either a much larger and older universe or in a multiverse.

Religious and philosophical interpretations

As a description of the origin of the universe, the Big Bang has significant bearing on religion and philosophy.[145][146] As a result, it has become one of the liveliest areas in the discourse between science and religion.[147] Some believe the Big Bang implies a creator,[148][149] and some see its mention in their holy books,[150] while others argue that Big Bang cosmology makes the notion of a creator superfluous.[146][151]

See also


  1. ^ There is no consensus about how long the Big Bang phase lasted. For some writers, this denotes only the initial singularity, for others the whole history of the universe. Usually, at least the first few minutes (during which helium is synthesized) are said to occur "during the Big Bang".
  4. ^ Strictly, dark energy in the form of a cosmological constant drives the universe towards a flat state; however, our universe remained close to flat for several billion years before the dark energy density became significant.


  2. ^ Kurki-Suonio, Hannu (2018). "Cosmology I" (PDF). University of Helsinki. p. 9-10. Retrieved 2019.
  3. ^ Kornreich, Dave (27 June 2015). "Can we find the place where the Big Bang happened? (Intermediate)". Ask an Astronomer, Cornell University. Retrieved 2018.
  4. ^ Silk, Joseph (2009). Horizons of Cosmology. Templeton Press. p. 208.
  5. ^ Singh, Simon (2005). Big Bang: The Origin of the Universe. Harper Perennial. p. 560. Bibcode:2004biba.book.....S.
  6. ^ Wollack, Edward J. (10 December 2010). "Cosmology: The Study of the Universe". Universe 101: Big Bang Theory. NASA. Archived from the original on 14 May 2011. Retrieved 2017. The second section discusses the classic tests of the Big Bang theory that make it so compelling as the likely valid description of our universe.
  8. ^ "Big-bang model". Encyclopædia Britannica. Retrieved 2015.
  10. ^ Kragh, Helge (1996). Cosmology and Controversy. Princeton University Press. pp. 318, 319. ISBN 978-0-691-02623-7. At the same time that observations tipped the balance definitely in favor of relativistic big-bang theory, ...
  13. ^ "Planck reveals an almost perfect universe". PLANCK. ESA. 21 March 2013. Retrieved 2017.
  14. ^ a b c d e f Peebles, P. J. E.; Ratra, Bharat (2003). "The cosmological constant and dark energy". Reviews of Modern Physics. 75 (2): 559-606. arXiv:astro-ph/0207347. Bibcode:2003RvMP...75..559P. doi:10.1103/RevModPhys.75.559.
  15. ^ Friedman, A. (1922). "Über die Krümmung des Raumes". Zeitschrift für Physik. 10 (1): 377-386. Bibcode:1922ZPhy...10..377F. doi:10.1007/BF01332580. Translated in Friedmann, A. (1999). "On the Curvature of Space". General Relativity and Gravitation. 31 (12): 1991-2000. Bibcode:1999GReGr..31.1991F. doi:10.1023/A:1026751225741.
  16. ^ Block, David L. (2012). Georges Lemaître and Stigler's Law of Eponymy. Astrophysics and Space Science Library. 395. pp. 89-96. arXiv:1106.3928v2. Bibcode:2012ASSL..395...89B. doi:10.1007/978-3-642-32254-9_8. ISBN 978-3-642-32253-2.
  17. ^ Reich, Eugenie Samuel (27 June 2011). "Edwin Hubble in translation trouble". Nature. doi:10.1038/news.2011.385. ISSN 1476-4687.
  18. ^ Livio, Mario (1 November 2011). "Mystery of the missing text solved". Nature. 479 (7372): 171-173. Bibcode:2011Natur.479..171L. doi:10.1038/479171a. PMID 22071745.
  19. ^ "Big bang theory is introduced - 1927". A Science Odyssey. WGBH. Retrieved 2014.
  21. ^ Belenkiy, Ari (2012). "Alexander Friedmann and the origins of modern cosmology". Physics Today. 65 (10): 38. Bibcode:2012PhT....65j..38B. doi:10.1063/PT.3.1750.
  23. ^ a b c d Hubble, E. (1929). "A Relation Between Distance and Radial Velocity Among Extra-Galactic Nebulae". Proceedings of the National Academy of Sciences. 15 (3): 168-73. Bibcode:1929PNAS...15..168H. doi:10.1073/pnas.15.3.168. PMC 522427. PMID 16577160.
  24. ^ Hooper, Dan (12 October 2019). "A Well-Deserved Physics Nobel - Jim Peebles' award honors modern cosmological theory at last". Scientific American. Retrieved 2019.
  25. ^ Couronne, Ivan (14 November 2019). "Top cosmologist's lonely battle against 'Big Bang' theory". Phys.org. Retrieved 2019.
  26. ^ Hawking, S. W.; Ellis, G. F. R. (1973). The Large-Scale Structure of Space-Time. Cambridge University Press. ISBN 978-0-521-20016-5.
  27. ^ Roos, M. (2008). "Expansion of the Universe - Standard Big Bang Model". In Engvold, O.; Stabell, R.; Czerny, B.; Lattanzio, J. (eds.). Astronomy and Astrophysics. Encyclopedia of Life Support Systems. UNESCO. arXiv:0802.2005. Bibcode:2008arXiv0802.2005R. This singularity is termed the Big Bang.
  28. ^ Drees, W. B. (1990). Beyond the big bang: quantum cosmologies and God. Open Court Publishing. pp. 223-224. ISBN 978-0-8126-9118-4.
  29. ^ Planck Collaboration (2016). "Planck 2015 results. XIII. Cosmological parameters (See PDF, page 32, Table 4, Age/Gyr, last column)". Astronomy & Astrophysics. 594: A13. arXiv:1502.01589. Bibcode:2016A&A...594A..13P. doi:10.1051/0004-6361/201525830.
  31. ^ Schewe, P. (2005). "An Ocean of Quarks". Physics News Update. 728 (1). Archived from the original on 23 April 2005.
  32. ^ Kolb and Turner (1988), chapter 6
  33. ^ Kolb and Turner (1988), chapter 7
  34. ^ a b c Kolb and Turner (1988), chapter 4
  35. ^ a b Peacock (1999), chapter 9
  36. ^ Loeb, Abraham (24 September 2014). "The Habitable Epoch of the Early Universe" (PDF). International Journal of Astrobiology. Cambridge University Press / Astronomy Department, Harvard University. 13 (4): 337-339. arXiv:1312.0613. Bibcode:2014IJAsB..13..337L. CiteSeerX doi:10.1017/S1473550414000196.
  40. ^ a b Spergel, D. N.; et al. (2003). "First year Wilkinson Microwave Anisotropy Probe (WMAP) observations: determination of cosmological parameters". The Astrophysical Journal Supplement. 148 (1): 175-194. arXiv:astro-ph/0302209. Bibcode:2003ApJS..148..175S. doi:10.1086/377226.
  41. ^ a b c d Jarosik, N.; et al. (2011). "Seven-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Sky Maps, Systematic Errors, and Basic Results" (PDF). The Astrophysical Journal Supplement Series. 192 (2): 39, Table 8. arXiv:1001.4744. Bibcode:2011ApJS..192...14J. doi:10.1088/0067-0049/192/2/14. Retrieved 2010.
  42. ^ Ivanchik, A. V.; Potekhin, A. Y.; Varshalovich, D. A. (1999). "The Fine-Structure Constant: A New Observational Limit on Its Cosmological Variation and Some Theoretical Consequences". Astronomy and Astrophysics. 343: 459. arXiv:astro-ph/9810166. Bibcode:1999A&A...343..439I.
  43. ^ Goodman, J. (1995). "Geocentrism Reexamined" (PDF). Physical Review D. 52 (4): 1821-1827. arXiv:astro-ph/9506068. Bibcode:1995PhRvD..52.1821G. doi:10.1103/PhysRevD.52.1821.
  44. ^ d'Inverno, R. (1992). "Chapter 23". Introducing Einstein's Relativity. Oxford University Press. ISBN 978-0-19-859686-8.
  46. ^ a b c Kolb and Turner (1988), chapter 3
  47. ^ "Hoyle on the Radio: Creating the 'Big Bang'". BBC News. Archived from the original on 26 May 2014. Retrieved 2017.
  48. ^ "Hoyle Scoffs at "Big Bang"". Cosmic Times. Archived from the original on 14 December 2016. Retrieved 2017.
  51. ^ a b Mitton (24 February 2011). Fred Hoyle: A Life in Science. Cambridge University Press. ISBN 978-1-139-49595-0."To create a picture in the mind of the listener, Hoyle had likened the explosive theory of the universe's origin to a 'big bang'"
  52. ^ Moskowitz, C. (25 September 2012). "Hubble Telescope Reveals Farthest View Into Universe Ever". Space.com. Retrieved 2012.
  53. ^ Slipher, V. M. (1913). "The Radial Velocity of the Andromeda Nebula". Lowell Observatory Bulletin. 1: 56-57. Bibcode:1913LowOB...2...56S.
  54. ^ Slipher, V. M. (1915). "Spectrographic Observations of Nebulae". Popular Astronomy. 23: 21-24. Bibcode:1915PA.....23...21S.
    (Translated in: Lemaître, G. (1931). "A Homogeneous Universe of Constant Mass and Growing Radius Accounting for the Radial Velocity of Extragalactic Nebulae". Monthly Notices of the Royal Astronomical Society. 91 (5): 483-490. Bibcode:1931MNRAS..91..483L. doi:10.1093/mnras/91.5.483.)
  57. ^ Lemaître, G. (1931). "The Evolution of the Universe: Discussion". Nature. 128 (3234): 699-701. Bibcode:1931Natur.128..704L. doi:10.1038/128704a0.
  58. ^ Christianson, E. (1995). Edwin Hubble: Mariner of the Nebulae. Farrar, Straus and Giroux. ISBN 978-0-374-14660-3.
  59. ^ Kragh, H. (1996). Cosmology and Controversy. Princeton University Press. ISBN 978-0-691-02623-7.
  60. ^ "People and Discoveries: Big Bang Theory". A Science Odyssey. PBS. Retrieved 2012.
  61. ^ Eddington, A. (1931). "The End of the World: from the Standpoint of Mathematical Physics". Nature. 127 (3203): 447-453. Bibcode:1931Natur.127..447E. doi:10.1038/127447a0.
  65. ^ Tolman, R. C. (1934). Relativity, Thermodynamics, and Cosmology. Clarendon Press. ISBN 978-0-486-65383-9. LCCN 34032023.
  66. ^ Zwicky, F. (1929). "On the Red Shift of Spectral Lines through Interstellar Space". Proceedings of the National Academy of Sciences. 15 (10): 773-779. Bibcode:1929PNAS...15..773Z. doi:10.1073/pnas.15.10.773. PMC 522555. PMID 16577237.
  67. ^ Hoyle, F. (1948). "A New Model for the Expanding Universe". Monthly Notices of the Royal Astronomical Society. 108 (5): 372-382. Bibcode:1948MNRAS.108..372H. doi:10.1093/mnras/108.5.372.
  68. ^ Alpher, R. A.; Bethe, H.; Gamow, G. (1948). "The Origin of Chemical Elements". Physical Review. 73 (7): 803-804. Bibcode:1948PhRv...73..803A. doi:10.1103/PhysRev.73.803.
  69. ^ Alpher, R. A.; Herman, R. (1948). "Evolution of the Universe". Nature. 162 (4124): 774-775. Bibcode:1948Natur.162..774A. doi:10.1038/162774b0.
  73. ^ Hawking, S.; Penrose, R. (27 January 1970). "The Singularities of Gravitational Collapse and Cosmology". Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences. 314 (1519): 529-548. Bibcode:1970RSPSA.314..529H. doi:10.1098/rspa.1970.0021. Retrieved 2015.
  74. ^ Guth, Alan (15 January 1981). "Inflationary universe: A possible solution to the horizon and flatness problems". Phys. Rev. D. 23 (2): 347-356. Bibcode:1981PhRvD..23..347G. doi:10.1103/PhysRevD.23.347.
  77. ^ Navabi, A. A.; Riazi, N. (2003). "Is the Age Problem Resolved?". Journal of Astrophysics and Astronomy. 24 (1-2): 3-10. Bibcode:2003JApA...24....3N. doi:10.1007/BF03012187.
  79. ^ a b Spergel, D. N.; et al. (2007). "Wilkinson Microwave Anisotropy Probe (WMAP) Three Year Results: Implications for Cosmology". Astrophysical Journal Supplement. 170 (2): 377-408. arXiv:astro-ph/0603449. Bibcode:2007ApJS..170..377S. doi:10.1086/513700.
  81. ^ Gladders, M. D.; et al. (2007). "Cosmological Constraints from the Red-Sequence Cluster Survey". The Astrophysical Journal. 655 (1): 128-134. arXiv:astro-ph/0603588. Bibcode:2007ApJ...655..128G. doi:10.1086/509909.
  82. ^ "Four Pillars". Cambridge Cosmology: Hot Big Bang. Retrieved 2016.
  84. ^ Cahn, R. (2010). "For a Comprehensive Space-Based Dark Energy Mission". Astro2010: The Astronomy and Astrophysics Decadal Survey. National Academies Press. 2010: 35. Bibcode:2009astro2010S..35B. Retrieved 2012.
  85. ^ Peacock (1999), chapter 3
  86. ^ Srianand, R.; Petitjean, P.; Ledoux, C. (2000). "The microwave background temperature at the redshift of 2.33771". Nature. 408 (6815): 931-935. arXiv:astro-ph/0012222. Bibcode:2000Natur.408..931S. doi:10.1038/35050020. PMID 11140672. Lay summaryEuropean Southern Observatory (December 2000).
  90. ^ Wright, E. L. (2004). "Theoretical Overview of Cosmic Microwave Background Anisotropy". In W. L. Freedman (ed.). Measuring and Modeling the Universe. Measuring and Modeling the Universe. Carnegie Observatories Astrophysics Series. Cambridge University Press. p. 291. arXiv:astro-ph/0305591. Bibcode:2004mmu..symp..291W. ISBN 978-0-521-75576-4.
  91. ^ Melchiorri, A.; et al. (1999). "A measurement of Omega from the North American test flight of BOOMERANG". The Astrophysical Journal. 536 (2): L63-L66. arXiv:astro-ph/9911445. Bibcode:2000ApJ...536L..63M. doi:10.1086/312744. PMID 10859119.
  92. ^ de Bernardis, P.; et al. (2000). "A Flat Universe from High-Resolution Maps of the Cosmic Microwave Background Radiation" (PDF). Nature. 404 (6781): 955-959. arXiv:astro-ph/0004404. Bibcode:2000Natur.404..955D. doi:10.1038/35010035. hdl:10044/1/60851. PMID 10801117.
  93. ^ Miller, A. D.; et al. (1999). "A Measurement of the Angular Power Spectrum of the Cosmic Microwave Background from l = 100 to 400". The Astrophysical Journal Letters. 524 (1): L1-L4. arXiv:astro-ph/9906421. Bibcode:1999ApJ...524L...1M. doi:10.1086/312293.
  94. ^ Steigman, G. (2006). "Primordial Nucleosynthesis: Successes And Challenges". International Journal of Modern Physics E. 15 (1): 1-36. arXiv:astro-ph/0511534. Bibcode:2006IJMPE..15....1S. CiteSeerX doi:10.1142/S0218301306004028.
  96. ^ a b Bertschinger, E. (2001). "Cosmological Perturbation Theory and Structure Formation". arXiv:astro-ph/0101009.
  97. ^ Bertschinger, E. (1998). "Simulations of Structure Formation in the Universe". Annual Review of Astronomy and Astrophysics. 36 (1): 599-654. Bibcode:1998ARA&A..36..599B. doi:10.1146/annurev.astro.36.1.599.
  98. ^ "BICEP2 2014 Results Release". National Science Foundation. 17 March 2014. Retrieved 2014.
  99. ^ Clavin, Whitney (17 March 2014). "NASA Technology Views Birth of the Universe". NASA. Retrieved 2014.
  102. ^ Fumagalli, M.; O'Meara, J. M.; Prochaska, J. X. (2011). "Detection of Pristine Gas Two Billion Years After the Big Bang". Science. 334 (6060): 1245-9. arXiv:1111.2334. Bibcode:2011Sci...334.1245F. doi:10.1126/science.1213581. PMID 22075722.
  105. ^ Srianand, R.; Noterdaeme, P.; Ledoux, C.; Petitjean, P. (2008). "First detection of CO in a high-redshift damped Lyman-? system". Astronomy and Astrophysics. 482 (3): L39. Bibcode:2008A&A...482L..39S. doi:10.1051/0004-6361:200809727.
  106. ^ Avgoustidis, A.; Luzzi, G.; Martins, C. J. A. P.; Monteiro, A. M. R. V. L. (2011). "Constraints on the CMB temperature-redshift dependence from SZ and distance measurements". Journal of Cosmology and Astroparticle Physics. 2012 (2): 013. arXiv:1112.1862. Bibcode:2012JCAP...02..013A. CiteSeerX doi:10.1088/1475-7516/2012/02/013.
  107. ^ Belusevic, R. (2008). Relativity, Astrophysics and Cosmology. Wiley-VCH. p. 16. ISBN 978-3-527-40764-4.
  108. ^ Ghosh, Pallab (11 February 2016). "Einstein's gravitational waves 'seen' from black holes". bbc.com. Retrieved 2017.
  109. ^ Billings, Lee (12 February 2016). "The Future of Gravitational Wave Astronomy". scientificamerican.com. Retrieved 2017.
  110. ^ Earman, John; Mosterín, Jesús (March 1999). "A Critical Look at Inflationary Cosmology". Philosophy of Science. 66 (1): 1-49. doi:10.1086/392675. JSTOR 188736.
  111. ^ Penrose, R. (1979). Hawking, S. W.; Israel, W. (eds.). Singularities and Time-Asymmetry. General Relativity: An Einstein Centenary Survey. Cambridge University Press. pp. 581-638.
  112. ^ Penrose, R. (1989). Fergus, E. J. (ed.). Difficulties with Inflationary Cosmology. Proceedings of the 14th Texas Symposium on Relativistic Astrophysics. New York Academy of Sciences. pp. 249-264. Bibcode:1989NYASA.571..249P. doi:10.1111/j.1749-6632.1989.tb50513.x.
  114. ^ Kolb and Turner, chapter 6
  116. ^ Mortonson, Michael J.; Weinberg, David H.; White, Martin (December 2013). "Dark Energy: A Short Review". Particle Data Group 2014 Review of Particle Physics. arXiv:1401.0046. Bibcode:2014arXiv1401.0046M.
    Mortonson, Michael J.; Weinberg, David H.; White, Martin (27 June 2014). "Dark Energy: A Short Review". LEVEL 5 -- A Knowledgebase for Extragalactic Astronomy and Cosmology, NASA/IPAC Extragalactic Database (NED). Jet Propulsion Laboratory, California Institute of Technology. arXiv:1401.0046. Bibcode:2014arXiv1401.0046M. Retrieved 2017.
  117. ^ Rugh, S. E.; Zinkernagel, H. (December 2002). "The quantum vacuum and the cosmological constant problem". Studies in History and Philosophy of Science Part B. 33 (4): 663-705. arXiv:hep-th/0012253. Bibcode:2002SHPMP..33..663R. doi:10.1016/S1355-2198(02)00033-3.
  118. ^ Keel, B. (October 2009) [Last changes: February 2015]. "Dark Matter". Retrieved 2013.
  119. ^ Yao, W. M.; et al. (2006). "Review of Particle Physics: Dark Matter" (PDF). Journal of Physics G. 33 (1): 1-1232. arXiv:astro-ph/0601168. Bibcode:2006JPhG...33....1Y. doi:10.1088/0954-3899/33/1/001.
  120. ^ Bullock, James (2010). "Notes on the Missing Satellites Problem". XX Canary Islands Winter School of Astrophysics on Local Group Cosmology. arXiv:1009.4505. Bibcode:2010arXiv1009.4505B.
  121. ^ Diemand, Jürg; Zemp, Marcel; Moore, Ben; Stadel, Joachim; Carollo, C. Marcella (December 2005). "Cusps in cold dark matter haloes". Monthly Notices of the Royal Astronomical Society. 364 (2): 665-673. arXiv:astro-ph/0504215. Bibcode:2005MNRAS.364..665D. doi:10.1111/j.1365-2966.2005.09601.x.
  122. ^ Dodelson, Scott (December 2011). "The Real Problem with MOND". International Journal of Modern Physics D. 20 (14): 2749-2753. arXiv:1112.1320. Bibcode:2011IJMPD..20.2749D. doi:10.1142/S0218271811020561.
  123. ^ a b c Kolb and Turner (1988), chapter 8
  124. ^ Spergel, D. N.; et al. (2007). "Three-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Implications for Cosmology" (PDF). The Astrophysical Journal Supplement Series. 170 (2): 377-408. arXiv:astro-ph/0603449. Bibcode:2007ApJS..170..377S. doi:10.1086/513700.
  125. ^ R. Penrose (2007). The Road to Reality. Vintage books. ISBN 978-0-679-77631-4.
  126. ^ Dicke, R. H.; Peebles, P. J. E. Hawking, S. W.; Israel, W. (eds.). The big bang cosmology--enigmas and nostrums. General Relativity: an Einstein centenary survey. Cambridge University Press. pp. 504-517.
  128. ^ Adams, Fred C. & Laughlin, Gregory (1997). "A dying Universe: the long-term fate and evolution of astrophysical objects". Reviews of Modern Physics. VI.D. 69 (2): 337-372. arXiv:astro-ph/9701131. Bibcode:1997RvMP...69..337A. doi:10.1103/RevModPhys.69.337..
  130. ^ "Brief Answers to Cosmic Questions". www.cfa.harvard.edu. Archived from the original on 13 April 2016. Retrieved 2017.
  131. ^ a b c d Davis, Tamara M.; Lineweaver, Charles H. (January 2004). "Expanding Confusion: Common Misconceptions of Cosmological Horizons and the Superluminal Expansion of the Universe". Publications of the Astronomical Society of Australia. 21 (1): 97-109. arXiv:astro-ph/0310808. Bibcode:2004PASA...21...97D. doi:10.1071/as03040.
  132. ^ "A Universe from Nothing". Astronomical Society of the Pacific. Archived from the original on 22 October 2013. Retrieved 2010. by Alexei V. Filippenko and Jay M. Pasachoff
  133. ^ "A Universe From Nothing lecture by Lawrence Krauss at AAI". 2009. Retrieved 2011.
  135. ^ Carroll, Sean M. (6 February 2018). "Why Is There Something, Rather Than Nothing?". Routledge Companion to the Philosophy of Physics. p. 9. arXiv:1802.02231v2.
  136. ^ "No Big Bang? Quantum equation predicts universe has no beginning". Retrieved 2017.
  137. ^ "The Beginning of TIme". Stephen Hawking. Retrieved 2017.
  138. ^ Hartle, J. H.; Hawking, S. (1983). "Wave Function of the Universe". Physical Review D. 28 (12): 2960-2975. Bibcode:1983PhRvD..28.2960H. doi:10.1103/PhysRevD.28.2960.
  139. ^ Langlois, D. (2003). "Brane Cosmology: An Introduction". Progress of Theoretical Physics Supplement. 148: 181-212. arXiv:hep-th/0209261. Bibcode:2002PThPS.148..181L. doi:10.1143/PTPS.148.181.
  141. ^ Than, K. (2006). "Recycled Universe: Theory Could Solve Cosmic Mystery". Space.com. Retrieved 2007.
  143. ^ Linde, A. (1986). "Eternal Chaotic Inflation". Modern Physics Letters A. 1 (2): 81-85. Bibcode:1986MPLA....1...81L. doi:10.1142/S0217732386000129.
  144. ^ Linde, A. (1986). "Eternally Existing Self-Reproducing Chaotic Inflationary Universe". Physics Letters B. 175 (4): 395-400. Bibcode:1986PhLB..175..395L. doi:10.1016/0370-2693(86)90611-8.
  146. ^ a b Frame, T. (2009). Losing my religion. UNSW Press. pp. 137-141. ISBN 978-1-921410-19-2.
  148. ^ Harris 2002, p. 129
  149. ^ Craig, William Lane (1999). "The ultimate question of origins: God and the beginning of the Universe". Astrophysics and Space Science. 269-270 (1-4): 723-740. doi:10.1007/978-94-011-4114-7_85. ISBN 978-94-010-5801-8.
  150. ^ Asad, Muhammad (1984). The Message of the Qu'rán. Gibraltar, Spain: Dar al-Andalus Limited. ISBN 978-1904510000.
  151. ^ Sagan, C. (1988). introduction to A Brief History of Time by Stephen Hawking. Bantam Books. pp. X. ISBN 978-0-553-34614-5. ... a universe with no edge in space, no beginning or end in time, and nothing for a Creator to do.


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