| Physical cosmology | |
| | Key topics | Universe · Big Bang
Age of the universe
Timeline of the Big Bang
Ultimate fate of the universe | | Early universe | Inflation · Nucleosynthesis
GWB · Neutrino Background
Cosmic microwave background | | Expanding universe | Redshift · Hubble's law
Metric expansion of space
Friedmann equations
FLRW metric | | Structure formation | Shape of the universe
Structure formation
Galaxy formation
Large-scale structure | | Components | Lambda-CDM model
Dark energy · Dark matter | | History | | Timeline of cosmology... | | Cosmology experiments | Observational cosmology
2dF · SDSS
CoBE · BOOMERanG · WMAP | | Scientists | | Einstein · Hawking . Friedman · Lemaître · Hubble · Penzias · Wilson · Gamow · Dicke · Zel'dovich · Mather · Smoot · others Physical cosmology, as a branch of astrophysics, is the study of the large-scale structure of the universe and is concerned with fundamental questions about its formation and evolution. ...
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The Universe is defined as the summation of all particles and energy that exist and the space-time in which all events occur. ...
According to the Big Bang model, the universe developed from an extremely dense and hot state. ...
The age of the universe, in Big Bang cosmology, refers to the time elapsed between the Big Bang and the present day. ...
This article does not cite any references or sources. ...
This article does not cite any references or sources. ...
In cosmology, Big Bang nucleosynthesis (or primordial nucleosynthesis) refers to the production of nuclei other than H-1, the normal, light hydrogen, during the early phases of the universe, shortly after the Big Bang. ...
This article or section is in need of attention from an expert on the subject. ...
The Cosmic Neutrino Background (CNB) is the background particle radiation composed of neutrinos. ...
In cosmology, the cosmic microwave background radiation (most often abbreviated CMB but occasionally CMBR, CBR or MBR, also referred as relic radiation) is a form of electromagnetic radiation discovered in 1965 that fills the entire universe. ...
Redshift of spectral lines in the optical spectrum of a supercluster of distant galaxies (right), as compared with that of the Sun (left). ...
Hubbles 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 a key part of sciences current understanding of the universe, whereby space itself is described by a metric which changes over time. ...
The Friedmann equations relate various cosmological parameters within the context of general relativity. ...
// The Friedmann-Lemaître-Robertson-Walker (FLRW) metric is an exact solution of the Einstein field equations of general relativity and which describes a homogeneous, isotropic expanding/contracting universe. ...
The shape of the Universe is an informal name for a subject of investigation within physical cosmology. ...
It has been suggested that this article or section be merged into Large-scale structure of the cosmos. ...
In astrophysics, the questions of galaxy formation and evolution are: How, from a homogeneous universe, did we obtain the very heterogeneous one we live in? How did galaxies form? How do galaxies change over time? A spectacular head-on collision between two galaxies is seen in this NASA Hubble Space...
Astronomy and cosmology examine the universe to understand the large-scale structure of the cosmos. ...
A pie chart indicating the proportional composition of different energy-density components of the universe. ...
In physical cosmology, dark energy is a hypothetical form of energy that permeates all of space and tends to increase the rate of expansion of the universe. ...
In astrophysics and cosmology, dark matter refers to hypothetical matter of unknown composition that does not emit or reflect enough electromagnetic radiation to be observed directly, but whose presence can be inferred from gravitational effects on visible matter. ...
This lists a timeline of cosmological theories and discoveries. ...
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. ...
In astronomy, the 2dF Galaxy Redshift Survey (Two-degree-Field Galaxy Redshift Gurvey), or 2dFGRS is a redshift survey conducted by the Anglo-Australian Observatory in the 1990s. ...
SDSS Logo The Sloan Digital Sky Survey or SDSS is a major multi-filter imaging and spectroscopic redshift survey using a dedicated 2. ...
The Cosmic Background Explorer (COBE), also referred to as Explorer 66, was the first satellite built dedicated to cosmology. ...
The Telescope being readied for launch The BOOMERanG experiment (Balloon Observations Of Millimetric Extragalactic Radiation and Geophysics) measured the cosmic microwave background radiation of a part of the sky during three sub-orbital (high altitude) balloon flights. ...
Artist depiction of the WMAP satellite at the L2 point The Wilkinson Microwave Anisotropy Probe (WMAP) is a NASA satellite whose mission is to survey the sky to measure the temperature of the radiant heat left over from the Big Bang. ...
“Einstein†redirects here. ...
Stephen Hawking. ...
Alexander Alexandrovich Friedman or Friedmann (ÐлекÑандр ÐлекÑандрович Фридман) (June 16, 1888 – September 16, 1925) was a Russian cosmologist and mathematician. ...
Father Georges-Henri Lemaître (July 17, 1894 – June 20, 1966) was a Belgian Roman Catholic priest, honorary prelate, professor of physics and astronomer. ...
Edwin Powell Hubble (November 20, 1889 – September 28, 1953) was an American astronomer. ...
Arno Allan Penzias (born April 26, 1933) is an American physicist and winner of the 1978 Nobel Prize in physics. ...
Robert Woodrow Wilson Robert Woodrow Wilson (born January 10, 1936) is an American physicist. ...
George Gamow (pronounced GAM-off) (March 4, 1904 – August 19, 1968) , born Georgiy Antonovich Gamov (Георгий Ðнтонович Гамов) was a Ukrainian born physicist and cosmologist. ...
Robert Henry Dicke (May 6, 1916 – March 4, 1997) was an American experimental physicist, who made important contributions to the fields of astrophysics, atomic physics, cosmology and gravity. ...
Yakov Borisovich Zeldovich (Russian:Яков БориÑович Зельдович) (March 8, 1914 – December 2, 1987) was a prolific Soviet physicist. ...
John Cromwell Mather (b. ...
George Fitzgerald Smoot III (born February 20, 1945) is an American astrophysicist and cosmologist awarded the 2006 Nobel Prize in Physics with John C. Mather for their discovery of the black body form and anisotropy of the cosmic microwave background radiation. This work helped cement the big-bang theory of...
| | This box: view • talk • edit | scenario in which the universe becomes too cold to sustain life due to continued expansion and the decay of free energy due to the action of entropy. The Big Freeze is a theory of a possible fate of the universe. The Big Freeze could occur if the universe's geometry is either flat or hyperbolic, as either of those would mean that the universe would expand indefinitely eventually reaching absolute zero (-273.15 °C or -459.67 °F, also defined as 0 K or 0 °R). The Universe is defined as the summation of all particles and energy that exist and the space-time in which all events occur. ...
The thermodynamic free energy is a measure of the amount of mechanical (or other) work that can be extracted from a system, and is helpful in engineering applications. ...
Ice melting - classic example of entropy increasing[1] described in 1862 by Rudolf Clausius as an increase in the disgregation of the molecules of the body of ice. ...
This article does not cite any references or sources. ...
Calabi-Yau manifold Geometry (Greek γεωμετÏία; geo = earth, metria = measure) is a part of mathematics concerned with questions of size, shape, and relative position of figures and with properties of space. ...
The Universe is defined as the summation of all particles and energy that exist and the space-time in which all events occur. ...
The metric expansion of space is a key part of sciences current understanding of the universe, whereby space itself is described by a metric which changes over time. ...
Absolute zero is the lowest possible temperature where nothing could be colder, and no heat energy remains in a substance. ...
Celsius is, or relates to, the Celsius temperature scale (previously known as the centigrade scale). ...
Fahrenheit is a temperature scale named after the German-Dutch physicist Daniel Gabriel Fahrenheit (1686–1736), who proposed it in 1724. ...
The kelvin (symbol: K) is a unit increment of temperature and is one of the seven SI base units. ...
Rankine is a now rarely used temperature scale named after the Scottish engineer and physicist William John Macquorn Rankine, who proposed it in 1859. ...
Geometry
For the universe to expand indefinitely, the shape of the universe as a whole needs to be flat or hyperbolic; this requirement stems from the density of the universe in those particular geometric shapes. There are three likely possibilities for the universe's shape. The Universe is defined as the summation of all particles and energy that exist and the space-time in which all events occur. ...
In physics, density is mass m per unit volume V. For the common case of a homogeneous substance, it is expressed as: where, in SI units: Ï (rho) is the density of the substance, measured in kg·m-3 m is the mass of the substance, measured in kg V is...
Possible Universe Geometries For other uses, see sphere (disambiguation). ...
For hyperbole, the figure of speech, see hyperbole. ...
Hyperbolic parabloid A model of an ellyptic hyperboloid of one sheet A saddle surface is a smooth surface all points of which are saddle points. ...
Density For the Big Freeze theory to happen, the shape of the Universe must be either hyperbolic or flat. If it is hyperbolic, which is usually pictured as a saddle shape, then the density must be lower than the critical density (which is approximately three hydrogen atoms per cubic meter), which means that the universe isn't heavy enough to collapse under gravity. If our Universe is flat, then the density will be exactly at the critical point, preventing the universe from collapsing as well. If the universe is heavier than the critical point, it will result in a shrinking universe, which leads to another theory, called the Big Crunch. For the Big Crunch to occur, the shape of the Universe would have to be spherical. The problem with measuring the current density of our Universe is that we cannot see most of the matter in it, and it is theorized that most of the universe may be made up of dark matter, a hypothetical, invisible form of matter in space. The shape of the Universe is an informal name for a subject of investigation within physical cosmology. ...
The Universe is defined as the summation of all particles and energy that exist and the space-time in which all events occur. ...
Gravity is a force of attraction that acts between bodies that have mass. ...
This article is about the cosmological theory. ...
In astrophysics and cosmology, dark matter refers to hypothetical matter of unknown composition that does not emit or reflect enough electromagnetic radiation to be observed directly, but whose presence can be inferred from gravitational effects on visible matter. ...
Expansion Expansion of the Universe is the entire basis of the Big Freeze theory. If the shape of the Universe is hyperbolic, then the Universe will reach a fixed expansion rate and expand forever, which means that the universe will never really "die". If the universe is flat, then the Universe will continue to expand until it reaches an expansion rate of zero; a Universe in this scenario would never "die" either. The Universe is defined as the summation of all particles and energy that exist and the space-time in which all events occur. ...
Problems The Law of conservation of energy states that energy cannot be created nor destroyed. Therefore, kinetic energy of particles (thermal energy) cannot reach absolute zero. Also, Newton's first law states that objects in motion stay in motion unless acted upon by a force. Therefore, particles would continue to perpetually roam the Universe, still possesing kinetic energy (thermal energy) on their endless trek across the Universe.
See also This article does not cite any references or sources. ...
This article is about the cosmological theory. ...
The heat death is a impossible final state of the universe, in which it has run down to a state of no free energy to sustain motion or life. ...
The Big Rip is a cosmological hypothesis about the Ultimate fate of the universe, in which the matter of the universe, from stars and galaxies to atoms and subatomic particles, are progressively torn apart by the expansion of the universe at a certain time in the future. ...
External links
| v • d • e Doomsday | | Doomsday | | Topics: Doomsday argument · Risks to civilization, humans and planet Earth · Human extinction · Ultimate fate of the universe · Big Rip · Big Freeze · Big Crunch · Heat death of the universe · Apocalypse · End of planet Earth · Apocalyptic and post-apocalyptic fiction Look up doomsday in Wiktionary, the free dictionary. ...
Look up doomsday in Wiktionary, the free dictionary. ...
The Doomsday argument (DA) is a probabilistic argument that claims to predict the future lifetime of the human race given only an estimate of the total number of humans born so far. ...
Risks to civilization, humans and planet Earth are existential risks that would imperil humankind as a whole and/or have major adverse consequences for the course of human civilization, human extinction or even the end of planet Earth. ...
Human extinction would be the extinction of the human species, Homo sapiens. ...
This article does not cite any references or sources. ...
The Big Rip is a cosmological hypothesis about the Ultimate fate of the universe, in which the matter of the universe, from stars and galaxies to atoms and subatomic particles, are progressively torn apart by the expansion of the universe at a certain time in the future. ...
This article is about the cosmological theory. ...
The heat death is a impossible final state of the universe, in which it has run down to a state of no free energy to sustain motion or life. ...
Look up Apocalypse in Wiktionary, the free dictionary. ...
The end of planet Earth refers to theories of when the Earth either completely ceases to exist as a planet or becomes uninhabitable for life. ...
It has been suggested that Post-holocaust be merged into this article or section. ...
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