This verification is a strong indication that our model of the universe is accurate. was approximately the particle wavelength squared, which is roughly As this field settled into its lowest energy state throughout the universe, it generated an enormous repulsive force that led to a rapid expansion of the metric that defines space itself. a About 4 billion years ago, it began slightly speeding up again. This page was last edited on 12 December 2020, at 00:34 (UTC). The picture shows the galaxy cluster XLSSC 006. The first generation of stars, known as Population III stars, formed within a few hundred million years after the Big Bang. If so, then a popular theory is that the universe will cool as it expands, eventually becoming too cold to sustain life. The Standard Model of cosmology is based on a model of spacetime called the Friedmann–Lemaître–Robertson–Walker (FLRW) metric. [32] (Much of the rest of its mass-energy is in the form of neutrinos and other relativistic particles[citation needed]). Einstein's theory of general relativity, announced in 1916, had led to various cosmological models, including Einstein's own model of a static universe. Current particle physics suggests asymmetries under which these conditions would be met, but these asymmetries appear to be too small to account for the observed baryon-antibaryon asymmetry of the universe. More exact knowledge of our current universe will allow these to be better understood. Aristotle's cosmology belonged to the class of steady-state theories in so far … In theory, the decoupled neutrinos should have had a very slight effect on the phase of the various CMB fluctuations. We know the quark soup exists because we have created similar conditions inside particle accelerators. After that moment, all distances throughout the universe began to increase from (perhaps) zero because the FLRW metric itself changed over time, affecting distances between all non-bound objects everywhere. It is not known exactly when the inflationary epoch ended, but it is thought to have been between 10−33 and 10−32 seconds after the Big Bang. ... the worldview of scientists also influences the development and progress of scientific theories. into our In Waves (Huygens Principle) which then explains Mach's Collisions between particles were too energetic to allow quarks to combine into mesons or baryons. Chemical equilibrium in QCD gas in the early universe. Just before recombination, the baryonic matter in the universe was at a temperature where it formed a hot ionized plasma. Read about Copernicus' heliocentric view, Descartes' vortices, Einstein's relativity revolution, the first big bang models and the startling new inflation and multiverse hypotheses. (Such dense pockets, if they existed, would have been extremely rare.) To explain the observed homogeneity of the universe, the duration in these models must be longer than 10−32 seconds. [55], These observations have narrowed down the period of time during which reionization took place, but the source of the photons that caused reionization is still not completely certain. ", "Scientists confirm most distant galaxy ever", "Astronomers Claim to Find the Most Distant Known Galaxies", "Hobby-Eberly Telescope Helps Astronomers Learn Secrets of One of Universe's Most Distant Objects", "Astronomers Spot Most Distant Galaxy—At Least For Now", "Cosmos Controversy: The Universe Is Expanding, but How Fast? Gravitational attraction also gradually pulls galaxies towards each other to form groups, clusters and superclusters. The spherical volume inside it is commonly referred to as the observable universe. The concept of inflation was introduced by cosmologist Alan Guth in … Red shifting describes the photons acquiring longer wavelengths and lower frequencies as the universe expanded over billions of years, so that they gradually changed from visible light to radio waves. The lepton epoch follows a similar path to the earlier hadron epoch. 800 B.C.E. Since the interaction was strong, the cross section Because this process was gradual, the Dark Ages only fully ended around 1 billion years, as the universe took its present appearance. Therefore dark matter collapses into huge but diffuse filaments and haloes, and not into stars or planets. Their light shows evidence of elements such as carbon, magnesium, iron and oxygen. As a result, the universe was opaque or "foggy". The rate of collisions per particle species can thus be calculated from the mean free path, giving approximately: For comparison, since the cosmological constant was negligible at this stage, the Hubble parameter was: where x ~ 102 was the number of available particle species. At this point non-linear structures begin to form, and the computational problem becomes much more difficult, involving, for example, N-body simulations with billions of particles. Steady-state theories. This release of photons is known as photon decoupling. ∼ The matter in the universe is around 84.5% cold dark matter and 15.5% "ordinary" matter. The present-day universe is understood quite well, but beyond about 100 billion years of cosmic time (about 86 billion years in the future), uncertainties in current knowledge mean that we are less sure which path our universe will take. This timeline of cosmological theories and discoveries is a chronological record of the development of humanity's understanding of the cosmos over the last two-plus millennia. The quark–gluon plasma that composes the universe cools until hadrons, including baryons such as protons and neutrons, can form. During the Dark Ages, the temperature of the universe cooled from some 4000 K to about 60 K (3727 Â°C to about −213 Â°C), and only two sources of photons existed: the photons released during recombination/decoupling (as neutral hydrogen atoms formed), which we can still detect today as the cosmic microwave background (CMB), and photons occasionally released by neutral hydrogen atoms, known as the 21 cm spin line of neutral hydrogen. This could result in a new big bang from the cyclic universe scenario. 3,100 B.C.E. These features make it possible to study the state of ionization at many different times in the past. In fact, almost no antibaryons are observed in nature. The universe has become transparent to visible light, radio waves and other electromagnetic radiation for the first time in its history. Random fluctuations could lead to some regions becoming dense enough to undergo gravitational collapse, forming black holes. Lemaître in 1927 (and, independently, Alexander Friedmann in 1922) discovered a family of solutions to If supersymmetry is a property of our universe, then it must be broken at an energy that is no lower than 1 TeV, the electroweak scale. The only photons (electromagnetic radiation, or "light") in the universe were those released during decoupling (visible today as the cosmic microwave background) and 21 cm radio emissions occasionally emitted by hydrogen atoms. Tiny ripples in the universe at this stage are believed to be the basis of large-scale structures that formed much later. Traditional big bang cosmology predicts a gravitational singularity before this time, but this theory relies on the theory of general relativity, which is thought to break down for this epoch due to quantum effects.[9]. Now, any cosmological theory purporting to explain the biblical account of creation must account for the vast dimensions of interstellar space, which cannot have been traversed by the astronomical bodies and objects within it during a time period of 6,000 earth years at the currently accepted maximum speed in Universe – the speed of light. A 1:7 ratio of hadrons would indeed produce the observed element ratios in the early as well as current universe. The masses of particles and their superpartners would then no longer be equal. As the universe expanded and cooled, it crossed transition temperatures at which forces separated from each other. The newly formed atoms—mainly hydrogen and helium with traces of lithium—quickly reach their lowest energy state (ground state) by releasing photons ("photon decoupling"), and these photons can still be detected today as the cosmic microwave background (CMB). / There is also currently an observational effort underway to detect the faint 21 cm spin line radiation, as it is in principle an even more powerful tool than the cosmic microwave background for studying the early universe. Lasting around 370,000 years. This should be cleared up … If this is true, at 30 billion years all other galaxies are pulled from our view and all evidence of the big bang is lost forever (it may be possible that future astronomers could deduce its existence using a few methods…but hopefully we keep good records). Initially leptons and antileptons are produced in pairs. / − As the universe's temperature continued to fall below 159.5±1.5 GeV, electroweak symmetry breaking happened. Ultimately, in the extreme future, the following scenarios have been proposed for the ultimate fate of the universe: The effect would be that the quantum fields that underpin all forces, particles and structures, would undergo a transition to a more stable form. 1965 Discovery of CMB So how does this prove the Big Bang Theory? The Standard Model of cosmology attempts to explain how the universe physically developed once that moment happened. As yet, no Population III stars have been found, so our understanding of them is based on computational models of their formation and evolution. The neutrinos from this event have a very low energy, around 10−10 times smaller than is possible with present-day direct detection. To give one example, eternal inflation theories propose that inflation lasts forever throughout most of the universe, making the notion of "N seconds since Big Bang" ill-defined. They can be huge as well as perhaps small—and non-metallic (no elements except hydrogen and helium). Someone is looking for the history of the big bang, creation of atoms, etc, only to find that he is looking at the history of the THEORIES about these matters. 9 billion years:our solar system forms (yay us!). After recombination and decoupling, the universe was transparent and had cooled enough to allow light to travel long distances, but there were no light-producing structures such as stars and galaxies. The larger stars have very short lifetimes compared to most Main Sequence stars we see today, so they commonly finish burning their hydrogen fuel and explode as supernovae after mere millions of years, seeding the universe with heavier elements over repeated generations. The Bolshoi Cosmological Simulation is a high precision simulation of this era. Other than perhaps some rare statistical anomalies, the universe was truly dark. These phase transitions in the universe's fundamental forces are believed to be caused by a phenomenon of quantum fields called "symmetry breaking". One of the theoretical products of this phase transition was a scalar field called the inflaton field. [5] Other theories suggest that they may have included small stars, some perhaps still burning today. These may also lead to unpredictable changes to the state of the universe which would not be likely to be significant on any smaller timescale. According to traditional Big Bang cosmology, the electroweak epoch began 10−36 seconds after the Big Bang, when the temperature of the universe was low enough (1028 K) for the electronuclear force to begin to manifest as two separate interactions, the strong and the electroweak interactions. Therefore, the universe could follow a variety of different paths beyond this time. {\displaystyle \rho } Modern scientific cosmology is usually considered to have begun in 1917 with Albert Einstein 's publication of his final modification of general relativity in the paper "Cosmological Considerations of the General Theory of Relativity" (although this paper was not widely available outside of Germany until the end of World War I). For about 6.6 million years, between about 10 to 17 million years after the Big Bang (redshift 137–100), the background temperature was between 273–373 K (0–100 Â°C), a temperature compatible with liquid water and common biological chemical reactions. This is computationally relatively easy to study. [notes 1]. New forces and particles would replace the present ones we know of, with the side effect that all current particles, forces and structures would be destroyed and subsequently (if able) reform into different particles, forces and structures. Composite subatomic particles emerge—including protons and neutrons—and from about 2 minutes, conditions are suitable for nucleosynthesis: around 25% of the protons and all the neutrons fuse into heavier elements, initially deuterium which itself quickly fuses into mainly helium-4. Dark energy is believed to act like a cosmological constant—a scalar field that exists throughout space. In other words, the farther they are from us, the faster they are flying away. {\displaystyle (k_{B}T/\hbar c)^{3}} (However the total matter in the universe is only 31.7%, much smaller than the 68.3% of dark energy.) A slight matter-antimatter asymmetry from the earlier phases (, Electrons and atomic nuclei first become bound to form neutral, The time between recombination and the formation of. It is not clear how this came about. On top of this, the image provides evidence supporting inflationary cosmology via the information that we can extract from it. Little is known about the details of these processes. [11][12][13][14][15] However, on 19 June 2014, lowered confidence in confirming the cosmic inflation findings was reported [14][16][17] and finally, on 2 February 2015, a joint analysis of data from BICEP2/Keck and the European Space Agency's Planck microwave space telescope concluded that the statistical "significance [of the data] is too low to be interpreted as a detection of primordial B-modes" and can be attributed mainly to polarized dust in the Milky Way.[18][19][20]. The FLRW metric very closely matches overwhelming other evidence, showing that the universe has expanded since the Big Bang. Its behaviour had originally been dominated by radiation (relativistic constituents such as photons and neutrinos) for the first 47,000 years, and since about 370,000 years of cosmic time, its behaviour had been dominated by matter. Ordinary matter gathers where dark matter is denser, and in those places it collapses into clouds of mainly hydrogen gas. [26], However, Big Bang cosmology makes many predictions about the CνB, and there is very strong indirect evidence that the CνB exists, both from Big Bang nucleosynthesis predictions of the helium abundance, and from anisotropies in the cosmic microwave background (CMB). A summary of the major theories and critical turning points in the history of cosmology, from Copernicus to Einstein to Linde. [23][24][better source needed], During the quark epoch the universe was filled with a dense, hot quark–gluon plasma, containing quarks, leptons and their antiparticles. Matter continues to draw together under the influence of gravity, to form galaxies. Although there was light, it was not possible to see, nor can we observe that light through telescopes. This is not apparent in everyday life, because it only happens at far higher temperatures than we usually see in our present universe. 380, 000 years: when the nearly uniform soup cooled to about 3000 Kelvin, atoms formed nuclei and electrons. [39] Around or shortly after 47,000 years, the densities of non-relativistic matter (atomic nuclei) and relativistic radiation (photons) become equal, the Jeans length, which determines the smallest structures that can form (due to competition between gravitational attraction and pressure effects), begins to fall and perturbations, instead of being wiped out by free streaming radiation, can begin to grow in amplitude. Some of these decoupled photons are captured by other hydrogen atoms, the remainder remain free.

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