|Universe · Big Bang|
Age of the universe
Timeline of the Big Bang
Ultimate fate of the universe
Observational cosmology is the study of the structure, the evolution and the origin of the universe through observation, using instruments such as telescopes and cosmic ray detectors. Physical cosmology, as a branch of Astronomy, is the study of the large-scale structure of the Universe and is concerned with fundamental questions about its The Universe is defined as everything that Physically Exists: the entirety of Space and Time, all forms of Matter, Energy The Big Bang is the cosmological model of the Universe that is best supported by all lines of scientific evidence and Observation. The age of the Universe is the time elapsed between the theory of the Big Bang and the present day This timeline of the Big Bang describes the events according to the Scientific theory of the Big Bang, using the cosmological time parameter of Comoving coordinates The ultimate fate of the universe is a topic in Physical cosmology. In Astronomy, the 2dF Galaxy Redshift Survey (Two-degree-Field Galaxy Redshift Survey 2dF or 2dFGRS is a Redshift survey conducted by the The Sloan Digital Sky Survey or SDSS is a major multi-filter imaging and spectroscopic Redshift survey using a dedicated 2 The BOOMERanG experiment ( B alloon O bservations O f M illimetric E xtragalactic R adiation an d G eophysics The Universe is defined as everything that Physically Exists: the entirety of Space and Time, all forms of Matter, Energy Observation is either an activity of a living being (such as a Human) which senses and assimilates the Knowledge of a Phenomenon, or the recording of data A telescope is an instrument designed for the observation of remote objects and the collection of Electromagnetic radiation. For the 1962 Bruce Conner film see Cosmic Ray (film Cosmic rays are energetic particles originating from space that impinge on
The science of physical cosmology as it is practiced today had its subject material defined in the years following the Shapley-Curtis debate when it was determined that the universe had a larger scale than the Milky Way galaxy. Physical cosmology, as a branch of Astronomy, is the study of the large-scale structure of the Universe and is concerned with fundamental questions about its This is about the infamous discussion of astronomy For the Dream Theater song about Stem cell research, see The Great Debate (song. The Universe is defined as everything that Physically Exists: the entirety of Space and Time, all forms of Matter, Energy The Milky Way (a translation of the Latin Via Lactea, in turn derived from the Greek Γαλαξίας (Galaxias sometimes referred to simply This was precipitated by observations that established the size and the dynamics of the cosmos that could be explained by Einstein's General Theory of Relativity. In Big Bang Cosmology, the observable universe is the region of space bounded by a Sphere, centered on the observer that is small enough that Albert Einstein ( German: ˈalbɐt ˈaɪ̯nʃtaɪ̯n; English: ˈælbɝt ˈaɪnstaɪn (14 March 1879 – 18 April 1955 was a German -born theoretical General relativity or the general theory of relativity is the geometric theory of Gravitation published by Albert Einstein in 1916 In its infancy, cosmology was a speculative science based on a very limited number of observations and characterized by a dispute between steady state theorists and promoters of Big Bang cosmology. Steady state is a more general situation than Dynamic equilibrium. The Big Bang is the cosmological model of the Universe that is best supported by all lines of scientific evidence and Observation. It was not until the 1990s and beyond that the astronomical observations would be able to eliminate competing theories and drive the science to the "Golden Age of Cosmology" which was heralded by David Schramm at a National Academy of Sciences colloquium in 1992. David Norman Schramm ( October 25, 1945 &ndash December 19, 1997) was an American Astrophysicist. The National Academy of Sciences (NAS is a corporation in the United States whose members serve Pro bono as "advisers to the nation on science 
Distance measurements in astronomy have historically been and continue to be confounded by considerable measurement uncertainty. Hubble's law is the statement in Physical cosmology that the Redshift in light coming from distant galaxies is proportional to their distance The cosmic distance ladder (also known as the Extragalactic Distance Scale) is the succession of methods by which astronomers determine the Distances to celestial In particular, while stellar parallax can be used to measure the distance to nearby stars, the observational limits imposed by the difficulty in measuring the minuscule parallaxes associated with objects beyond our galaxy meant that astronomers had to look for alternative ways to measure cosmic distances. Parallax is an apparent displacement or difference of orientation of an object viewed along two different lines of sight and is measured by the angle or semi-angle of inclination between To this end, a standard candle measurement for Cepheid variables was discovered by Henrietta Swan Leavitt in 1908 which would provide Edwin Hubble with the rung on the cosmic distance ladder he would need to determine the distance to spiral nebula. A standard candle is an astronomical object that has a known Luminosity. A Cepheid variable (pron ˈse-f(ē-id or ˈsē-f(ē-id or Cepheid is a member of a particular class of Variable stars notable for a fairly tight correlation Henrietta Swan Leavitt ( July 4 1868 &ndash December 12 1921) was an American Astronomer, and the Deaf daughter of a Edwin Powell Hubble ( November 20, 1889 – September 28, 1953) was an American astronomer. The cosmic distance ladder (also known as the Extragalactic Distance Scale) is the succession of methods by which astronomers determine the Distances to celestial A spiral galaxy is a Galaxy belonging to one of the three main classes of galaxy originally described by Edwin Hubble in his 1936 work “The Realm of the When Hubble trained the 100-inch Hooker Telescope at Mount Wilson Observatory, he was able to identify individual stars in those galaxies, and determine the distance to the galaxies by isolating individual Cepheids. The Mount Wilson Observatory (MWO is an Astronomical observatory in Los Angeles County California. The Mount Wilson Observatory (MWO is an Astronomical observatory in Los Angeles County California. A star is a massive luminous ball of plasma. The nearest star to Earth is the Sun, which is the source of most of the Energy on Earth A galaxy is a massive gravitationally bound system consisting of Stars an Interstellar medium of gas and dust, and Dark matter This firmly established the spiral nebula as being objects well outside the Milky Way galaxy. Determining the distance to "island universes", as they were dubbed in the popular media, established the scale of the universe and settled the Shapley-Curtis debate once and for all. 
By combining his distance measurements with Vesto Slipher's determinations of redshifts for these objects, Hubble was able to determine a corellation between the distance to galaxies and what was termed their "recessional velocities". Vesto Melvin Slipher ( November 11, 1875 &ndash November 8, 1969) was an American Astronomer. In Physics and Astronomy, redshift occurs when Electromagnetic radiation – usually Visible light – emitted or reflected by This correlation would come to be known as Hubble's Law and would serve as the observational foundation for the expanding universe theories on which cosmology is still based. Hubble's law is the statement in Physical cosmology that the Redshift in light coming from distant galaxies is proportional to their distance The metric expansion of space is the averaged increase of metric (i The publication of Hubble's data and the acceptance by the theorists of its theoertical implications in light of Einstein's General theory of relativity is considered the beginning of the modern science of cosmology. General relativity or the general theory of relativity is the geometric theory of Gravitation published by Albert Einstein in 1916 
Determination of the cosmic abundance of elements has a history dating back to early spectroscopic measurements of light from astronomical objects and the identification of emission and absorption lines which corresponded to particular electronic transitions in chemical elements identified on Earth. Cosmochemistry is concerned with the origin and development of the elements and their Isotopes primarily within the Solar System. Astrochemistry is the study of the Chemical elements found in outer space generally on larger scales than the Solar System, particularly in molecular gas clouds See also Abundances of the elements (data page The abundance of a Chemical element measures how relatively common the element is or how much of the element Spectroscopy was originally the study of the interaction between Radiation and Matter as a function of Wavelength (λ A spectral line is a dark or bright line in an otherwise uniform and continuous spectrum, resulting from an excess or deficiency of photons in a narrow frequency range compared A spectral line is a dark or bright line in an otherwise uniform and continuous spectrum, resulting from an excess or deficiency of photons in a narrow frequency range compared A chemical element is a type of Atom that is distinguished by its Atomic number; that is by the number of Protons in its nucleus. For example, the element Helium was first identified through its spectroscopic signature in the Sun before it was isolated as a gas on Earth. Helium ( He) is a colorless odorless tasteless non-toxic Inert Monatomic Chemical The Sun (Sol is the Star at the center of the Solar System. 
Computing relative abundances was achieved through corresponding spectroscopic observations to measurements of the elemental composition of meteorites. A meteorite is a natural object originating in Outer space that survives an impact with the Earth 's surface
A compilation of results is found here. In Cosmochemistry, the Cosmochemical Periodic Table of the Elements in the Solar System is a Periodic table that lists all known chemical elements.
A cosmic microwave background was predicted in 1948 by George Gamow and Ralph Alpher, and by Alpher and Robert Herman as due to the hot big bang model. This article concerns the accidental discovery of Cosmic microwave background radiation. George Gamow (pronounced as ˈgamof ( March 4, 1904 &ndash August 19, 1968), born Georgiy Antonovich Gamov (Георгий Антонович Ralph Asher Alpher ( February 3, 1921 - August 12, 2007) was a U Robert Herman ( August 29, 1914 - February 13, 1997) was a United States scientist best known for his work with Ralph Alpher The Big Bang is the cosmological model of the Universe that is best supported by all lines of scientific evidence and Observation. Moreover, Alpher and Herman were able to estimate the temperature, but their results were not widely discussed in the community. Their prediction was rediscovered by Robert Dicke and Yakov Zel'dovich in the early 1960s with the first published recognition of the CMB radiation as a detectable phenomenon appeared in a brief paper by Soviet astrophysicists A. G. Doroshkevich and Igor Novikov, in the spring of 1964. Robert Henry Dicke ( May 6 1916 &ndash March 4 1997) was an American Physicist, who made important contributions to the fields of Yakov Borisovich Zel'dovich (Яков Борисович Зельдович ( March 8, 1914 &ndash December 2, 1987) was a prolific Soviet The Union of Soviet Socialist Republics (USSR was a constitutionally Socialist state that existed in Eurasia from 1922 to 1991 A G Doroshkevich is a Russian (and former Soviet) theoretical astrophysicist and cosmologist. Igor Dmitriyevich Novikov (И́горь Дми́триевич Но́виков (born November 10, 1935 in Moscow) is a Russian (and former  In 1964, David Todd Wilkinson and Peter Roll, Dicke's colleagues at Princeton University, began constructing a Dicke radiometer to measure the cosmic microwave background. For the Footballer please see David Wilkinson (footballer David Todd Wilkinson ( 13 May 1935 &ndash 5 September 2002 Princeton University is a private Coeducational research university located in Princeton, New Jersey.  In 1965, Arno Penzias and Robert Woodrow Wilson at the Crawford Hill location of Bell Telephone Laboratories in nearby Holmdel Township, New Jersey had built a Dicke radiometer that they intended to use for radio astronomy and satellite communication experiments. Arno Allan Penzias (born April 26, 1933) is an American Physicist and Nobel laureate in physics. Robert Woodrow Wilson (born January 10, 1936) is an American Astronomer, Nobel laureate in physics, who with Arno Allan Crawford Hill (40 23' 28" N 74 11'07" W is located in Holmdel Township, New Jersey, United States Bell Laboratories (also known as Bell Labs and formerly known as AT&T Bell Laboratories and Bell Telephone Laboratories) is the Research organization Holmdel Township is a township in Monmouth County, New Jersey, United States. Their instrument had an excess 3. 5 K antenna temperature which they could not account for. In electronics noise temperature is a temperature (in degrees Kelvin assigned to a component such that the noise power delivered by the noisy component to a noiseless matched resistor After receiving a telephone call from Crawford Hill, Dicke famously quipped: "Boys, we've been scooped. " A meeting between the Princeton and Crawford Hill groups determined that the antenna temperature was indeed due to the microwave background. Penzias and Wilson received the 1978 Nobel Prize in Physics for their discovery. The Nobel Prize in Physics (Nobelpriset i fysik is awarded once a year by the Royal Swedish Academy of Sciences.
Today, observational cosmology continues to test the predictions of theoretical cosmology and has led to the refinement of cosmological models. For example, the observational evidence for dark matter has heavily influenced theoretical modeling of structure and galaxy formation. In Physics and cosmology, dark matter is hypothetical Matter that does not interact with the electromagnetic force but whose presence can be inferred from Structure formation refers to a fundamental problem in Physical cosmology. The study of galaxy formation and evolution is concerned with the processes that formed a heterogeneous universe from a homogeneous beginning the formation of the first galaxies the way When trying to calibrate the Hubble diagram with accurate supernova standard candles, observational evidence for dark energy was obtained in the late 1990s. A supernova (plural supernovae or supernovas) is a stellar Explosion. A standard candle is an astronomical object that has a known Luminosity. In Physical cosmology, dark energy is a hypothetical exotic form of Energy that permeates all of space and tends to increase the rate of expansion of the universe These observations have been incorporated into a six-parameter framework known as the Lambda-CDM model which explains the evolution of the universe in terms of its constituent material. &LambdaCDM or Lambda-CDM is an abbreviation for Lambda-Cold Dark Matter. This model has subsequently been verified by detailed observations of the cosmic microwave background, especially through the WMAP experiment.
Included here are the modern observational efforts that have directly influenced cosmology.
With the advent of automated telescopes and improvements in spectroscopes, a number of collaborations have been made to map the universe in redshift space. In Astronomy, a redshift survey, or galaxy survey, is a survey of a section of the sky to measure the Redshift of astronomical objects A telescope is an instrument designed for the observation of remote objects and the collection of Electromagnetic radiation. Astronomical spectroscopy is the technique of Spectroscopy used in Astronomy. In Physics and Astronomy, redshift occurs when Electromagnetic radiation – usually Visible light – emitted or reflected by By combining redshift with angular position data, a redshift survey maps the 3D distribution of matter within a field of the sky. These observations are used to measure properties of the large-scale structure of the universe. In Physical cosmology, the term large-scale structure refers to the characterization of observable distributions of Matter and Light The Great Wall, a vast supercluster of galaxies over 500 million light-years wide, provides a dramatic example of a large-scale structure that redshift surveys can detect. The Great Wall (also called Coma Wall) sometimes specifically referred to as the CfA2 Great Wall, is the second largest known super-structure in the Superclusters are large groupings of smaller galaxy groups and clusters, and are among the largest structures of the Cosmos. A light-year or light year (symbol ly) is a unit of Length, equal to just under ten trillion Kilometres As defined by 
The first redshift survey was the CfA Redshift Survey, started in 1977 with the initial data collection completed in 1982. The Center for Astrophysics (CfA Redshift Survey was the first attempt to map the Large-scale structure of the universe Also 1977 (album by Ash. Year 1977 ( MCMLXXVII) was a Common year starting on Saturday (link displays Year 1982 ( MCMLXXXII) was a Common year starting on Friday (link displays the 1982 Gregorian calendar)  More recently, the 2dF Galaxy Redshift Survey determined the large-scale structure of one section of the Universe, measuring z-values for over 220,000 galaxies; data collection was completed in 2002, and the final data set was released 30 June 2003. In Astronomy, the 2dF Galaxy Redshift Survey (Two-degree-Field Galaxy Redshift Survey 2dF or 2dFGRS is a Redshift survey conducted by the A data set (or dataset) is a collection of Data, usually presented in tabular form Events 350 - Roman usurper Nepotianus, of the Constantinian dynasty, is defeated and killed by troops of the Usurper Year 2003 ( MMIII) was a Common year starting on Wednesday of the Gregorian calendar.  (In addition to mapping large-scale patterns of galaxies, 2dF established an upper limit on neutrino mass. Neutrinos are Elementary particles that travel close to the Speed of light, lack an Electric charge, are able to pass through ordinary matter almost ) Another notable investigation, the Sloan Digital Sky Survey (SDSS), is ongoing as of 2005 and aims to obtain measurements on around 100 million objects. The Sloan Digital Sky Survey or SDSS is a major multi-filter imaging and spectroscopic Redshift survey using a dedicated 2 Year 2005 ( MMV) was a Common year starting on Saturday (link displays full calendar of the Gregorian calendar.  SDSS has recorded redshifts for galaxies as high as 0. 4, and has been involved in the detection of quasars beyond z = 6. A quasar (contraction of QUASi-stellAR radio source) is an extremely powerful and distant Active galactic nucleus. The DEEP2 Redshift Survey uses the Keck telescopes with the new "DEIMOS" spectrograph; a follow-up to the pilot program DEEP1, DEEP2 is designed to measure faint galaxies with redshifts 0. The DEEP2 Survey or DEEP2 is a Redshift survey of the Redshift ~1 universe The W M Keck Observatory is a two-telescope Astronomical observatory at the 4145 meter (13600 ft summit of Mauna Kea in Hawai'i. A spectrometer is an Optical instrument used to measure properties of Light over a specific portion of the Electromagnetic spectrum, typically used 7 and above, and it is therefore planned to provide a complement to SDSS and 2dF. 
Subsequent to the discovery of the CMB, hundreds of cosmic microwave background experiments have been conducted to measure and characterize the signatures of the radiation. See also Discovery of the cosmic microwave background There have been a variety of Experiments to measure the Cosmic microwave background radiation anisotropies The most famous experiment is probably the NASA Cosmic Background Explorer (COBE) satellite that orbited in 1989–1996 and which detected and quantified the large scale anisotropies at the limit of its detection capabilities. The National Aeronautics and Space Administration ( NASA, ˈnæsə is an agency of the United States government, responsible for the nation's public space program Year 1989 ( MCMLXXXIX) was a Common year starting on Sunday (link displays 1989 Gregorian calendar) Year 1996 ( MCMXCVI) was a Leap year starting on Monday (link will display full 1996 Gregorian calendar) Inspired by the initial COBE results of an extremely isotropic and homogeneous background, a series of ground- and balloon-based experiments quantified CMB anisotropies on smaller angular scales over the next decade. The primary goal of these experiments was to measure the angular scale of the first acoustic peak, for which COBE did not have sufficient resolution. These measurements were able to rule out cosmic strings as the leading theory of cosmic structure formation, and suggested cosmic inflation was the right theory. A cosmic string is a hypothetical 1-dimensional (spatially Topological defect in various fields In Physical cosmology, cosmic inflation is the idea that the nascent Universe passed through a phase of exponential expansion that During the 1990s, the first peak was measured with increasing sensitivity and by 2000 the BOOMERanG experiment reported that the highest power fluctuations occur at scales of apporoximately one degree. The BOOMERanG experiment ( B alloon O bservations O f M illimetric E xtragalactic R adiation an d G eophysics Together with other cosmological data, these results implied that the geometry of the Universe is flat. The intuitive idea of flatness is important in several fields A number of ground-based interferometers provided measurements of the fluctuations with higher accuracy over the next three years, including the Very Small Array, Degree Angular Scale Interferometer (DASI) and the Cosmic Background Imager (CBI). Interferometry is the technique of using the pattern of Interference created by the superposition of two or more Waves to diagnose the properties of The Very Small Array is a 14-element interferometric radio telescope operating between 26 and 36 GHz that is used to study the Cosmic microwave background radiation The Degree Angular Scale Interferometer ( DASI) is a telescope located in Antarctica. The Cosmic Background Imager (or CBI) is a 13-element Interferometer perched at an elevation of 5080 Metres (16700 feet at Llano de Chajnantor DASI made the first detection of the polarization of the CMB and the CBI provided the first E-mode spectrum with compelling evidence that it is out of phase with the T-mode spectrum.
In June 2001, NASA launched a second CMB space mission, WMAP, to make much more precise measurements of the large scale anisotropies over the full sky. June 2001: January - February - March - April - May - June - July - August - September The National Aeronautics and Space Administration ( NASA, ˈnæsə is an agency of the United States government, responsible for the nation's public space program The first results from this mission, disclosed in 2003, were detailed measurements of the angular power spectrum to below degree scales, tightly constraining various cosmological parameters. The results are broadly consistent with those expected from cosmic inflation as well as various other competing theories, and are available in detail at NASA's data center for Cosmic Microwave Background (CMB) (see links below). In Physical cosmology, cosmic inflation is the idea that the nascent Universe passed through a phase of exponential expansion that Although WMAP provided very accurate measurements of the large angular-scale fluctuations in the CMB (structures about as large in the sky as the moon), it did not have the angular resolution to measure the smaller scale fluctuations which had been observed using previous ground-based interferometers. Interferometry is the technique of using the pattern of Interference created by the superposition of two or more Waves to diagnose the properties of
A third space mission, the Planck Surveyor, is to be launched in 2007. The Planck satellite is a Spacecraft built in the Cannes Mandelieu Space Center, that is designed to observe the anisotropies of the cosmic microwave Planck employs both HEMT radiometers as well as bolometer technology and will measure the CMB on smaller scales than WMAP. A bolometer is a device for measuring the energy of incident Electromagnetic radiation. Unlike the previous two space missions, Planck is a collaboration between NASA and ESA (the European Space Agency). The European Space Agency ( ESA) established in 1975 is an intergovernmental organisation dedicated to the exploration of space, currently with 17 member Its detectors got a trial run at the Antarctic Viper telescope as ACBAR (Arcminute Cosmology Bolometer Array Receiver) experiment – which has produced the most precise measurements at small angular scales to date – and at the Archeops balloon telescope. The Viper Telescope is used to view mainly Cosmic background radiation. ACBAR is an experiment to measure the anisotropy of the Cosmic microwave background. Archeops is a balloon-borne instrument dedicated to measure the Cosmic microwave background (CMB temperature anisotropies
Additional ground-based instruments such as the South Pole Telescope in Antarctica and the proposed Clover Project, Atacama Cosmology Telescope and the QUIET telescope in Chile will provide additional data not available from satellite observations, possibly including the B-mode polarization. The South Pole Telescope (SPT is a 10 meter diameter telescope located at the Amundsen-Scott South Pole Station, Antarctica Clover is an experiment to measure the Polarization of the Cosmic Microwave Background. The Atacama Cosmology Telescope ( ACT) is a six-metre telescope on Cerro Toco in the Atacama Desert in the north of Chile. QUIET is an Astronomy Experiment to study the polarization of the Cosmic microwave background radiation. Chile, officially the Republic of Chile ( Spanish:) is a country in South America occupying a long and narrow Coastal strip wedged between the
The brightest sources of low-frequency radio emission (10 MHz and 100 GHz) are radio galaxies which can be observed out to extremely high redshifts. Radio galaxies and their relatives radio-loud Quasars and Blazars, are types of Active galaxy that are very luminous at radio wavelengths (up These are subsets of the active galaxies that have extended features known as lobes and jets which extend away form the galactic nucleus distances on the order of megaparsecs. An active galactic nucleus ( AGN) is a compact region at the centre of a Galaxy which has a much higher than normal luminosity over some or all of the Electromagnetic History The first direct measurements of an object at interstellar distances were undertaken by German Astronomer Friedrich Wilhelm Bessel in 1838 Because radio galaxies are so bright, astronomers have used them to probe extreme distances and early times in the evolution of the universe.
It is a prediction of the Big Bang model that the universe is filled with a neutrino background radiation, analogous to the cosmic microwave background radiation. The cosmic neutrino background (CνB is the universe's background particle radiation composed of Neutrinos Like the Cosmic microwave background radiation The Big Bang is the cosmological model of the Universe that is best supported by all lines of scientific evidence and Observation. The cosmic neutrino background (CνB is the universe's background particle radiation composed of Neutrinos Like the Cosmic microwave background radiation The microwave background is a relic from when the universe was about 380,000 thousand years old, but the neutrino background is a relic from when the universe was about two seconds old.
If this neutrino radiation could be observed, it would be a window into very early stages of the universe. Unfortunately, these neutrinos would now be very cold, and so they are effectively impossible to observe directly.