FACTOID # 20: Statistically, Delaware bears more cost of the US Military than any other state.
 
 Home   Encyclopedia   Statistics   States A-Z   Flags   Maps   FAQ   About 
   
 
WHAT'S NEW
 

SEARCH ALL

FACTS & STATISTICS    Advanced view

Search encyclopedia, statistics and forums:

 

 

(* = Graphable)

 

 


Encyclopedia > Age of the Universe
Physical cosmology
Universe · Big Bang
Age of the universe
Timeline of the Big Bang
Ultimate fate of the universe
This box: view  talk  edit

The age of the universe is the time elapsed between the Big Bang and the present day. Current observations suggest that this is about 13.73 billion years, with an uncertainty of about 120 million years.[1] This article is about the physics subject. ... For other uses, see Universe (disambiguation). ... For other uses, see Big Bang (disambiguation). ... A graphical timeline is available here: Graphical timeline of the Big Bang This box:      This timeline of the Big Bang describes the events that have occurred and will occur according to the scientific theory of the Big Bang, using the cosmological time parameter of comoving coordinates. ... This box:      The ultimate fate of the universe is a topic in physical cosmology. ... 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. ... CMB redirects here. ... This article is about the physical phenomenon. ... This box:      Hubbles law is a statement in physical cosmology which states 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. ... For other uses, see Dark matter (disambiguation). ... 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 William Hawking, CH, CBE, FRS, FRSA, (born 8 January 1942) is a British theoretical physicist. ... Alexander Alexandrovich Friedman or Friedmann (Александр Александрович Фридман) (June 16, 1888 – September 16, 1925) was a Russian cosmologist and mathematician. ... Monsignor Georges Lemaître, priest and scientist. ... 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 Антонович 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 Борисович 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 is a list of cosmologists. ... A creation myth is a supernatural mytho-religious story or explanation that describes the beginnings of humanity, earth, life, and the universe (cosmogony),[1] usually as a deliberate act of creation by a supreme being. ... For other uses, see Universe (disambiguation). ... For other uses, see Big Bang (disambiguation). ... This box:      This article is about scientific estimates of the age of the universe. ... One thousand million (1,000,000,000) is the natural number following 999,999,999 and preceding 1,000,000,001. ...

Contents

Observational limits on the age of the universe

Since the universe must be at least as old as the oldest thing in it, there are a number of observations which limit the age of the universe. These include the temperature of the coolest white dwarfs, and the turnoff point of the red dwarfs. This article or section does not adequately cite its references or sources. ... Red dwarfs constitute the majority of all stars According to the Hertzsprung-Russell diagram, a red dwarf star is a small and relatively cool star, of the main sequence, either late K or M spectral type. ...


Common Misconceptions

It is currently not known if there was anything before the Big Bang. "Age of the universe" is to some extent a widely accepted misnomer for "time since the Big Bang". It in no way denotes that there was nothing before the Big Bang or even that the universe had a beginning. It merely denotes the time from when the observable universe started expanding to now[2].


As such, the fact that it has been empirically and scientifically shown with an infinitesimally small degree of uncertainty, that the observable universe is no less than approximately 13.37 billion years old, invalidates any other concept of the observable universe having started at a point less than 13 billion years ago. Arguments could be made for an older universe, but they would have no scientific standing until evidence could be shown for this. Scientists at the moment are limited to going back so far in time, if there was anything before the Big Bang, remains to be seen. Either way, as of this moment, the Big Bang Theory has nothing to do with the origin of the observable universe.


All preceding and following mentions of the word 'universe' refer only to the observable universe, that is, the universe which as we know it being possibly limited to the range of our best instruments. It could either be that all we observe is all there is, or that there might be a few more fringe stars that we currently haven't been able to detect, or that there are entirely different universes expanding out in the cosmos, but with no evidence to lend any scientific credence to these ideas, they are only hypothetical and so we are limited to the observable universe. The use of the phrase "limited to the observable universe" is not meant to be an implication of a non-observable supernatural aspect to the universe, but merely that science studies all that which can be measured or has any effect on observable events.


In most popularized science sources, the Big Bang Theory is often described with something like "The universe came into being due to the explosion of a point in which all matter was concentrated." Not surprisingly, this is probably the standard impression which most people have of the theory. Occasionally, one even hears "In the beginning, there was nothing, which exploded."


There are several misconceptions hidden in these statements:

 * The Big Bang Theory is not about the origin of the universe. Rather, its primary focus is the development of the universe over time. * Big Bang Theory does not imply that the universe was ever point-like. * The origin of the universe was not an explosion of matter into already existing space. 

Current hypotheses and research is being conducted to the end of better understanding the expansion of the universe and what, if anything, happened before the Big Bang.


Explanation

The Lambda-CDM concordance model describes the development of the universe from a very uniform, hot, dense primordial state to its present state over a span of about 13.7 billion years of cosmological time. This model is well understood theoretically and strongly supported by recent high-precision astronomical observations such as WMAP. In contrast, theories of the origin of the primordial state remain very speculative. The dominant theory, inflation, as well as the recent ekpyrotic scenario, suggest that the Big Bang cosmos that we observe may be a part of a larger universe with very different physical properties and with a history extending back longer than 13.7 billion years. It is not yet clear whether these ideas are testable, even in principle. A pie chart indicating the proportional composition of different energy-density components of the universe. ... A graphical timeline is available here: Graphical timeline of the Big Bang This timeline of the Big Bang describes the events that have occurred and will occur according to the scientific theory of the Big Bang. ... 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. ... The ekpyrotic universe or ekpyrotic scenario is a cosmological theory of the origin of the universe. ...


If one extrapolates the Lambda-CDM model backward from the earliest well-understood state, it quickly (within a small fraction of a second) reaches a mathematical singularity called the "Big Bang singularity." This singularity is not considered to have any physical significance, but it is convenient to quote times measured "since the Big Bang," even though they do not correspond to a physically measurable time. For example, "10−6 second after the Big Bang" is a well-defined era in the universe's evolution. In one sense it would be more meaningful to refer to the same era as "13.7 billion years minus 10−6 seconds ago," but this is unworkable since the latter time interval is swamped by uncertainty in the former. A gravitational singularity (sometimes spacetime singularity) is, approximately, a place where quantities which are used to measure the gravitational field become infinite. ...


Though the universe might in theory have a longer history, cosmologists presently use "age of the universe" to mean the duration of the Lambda-CDM expansion, or equivalently the elapsed time since the Big Bang.


Age as a function of cosmological parameters

The age of the universe can be determined by measuring the Hubble constant today and extrapolating back in time with the observed value of density parameters (Ω). Before the discovery of dark energy, it was believed that the universe was matter dominated and so Ω on this graph corresponds to Ωm. Note that the accelerating universe has the greatest age while the Big Crunch universe has the smallest age.
The value of the age correction factor F is shown as a function of two cosmological parameters: the current fractional matter density Ωm and cosmological constant density ΩΛ. The best-fit values of these parameters are shown by the box in the upper left; the matter-dominated universe is shown by the star in the lower-right.

The problem of determining the age of the universe is closely tied to the problem of determining the values of the cosmological parameters. Today this is largely carried out in the context of the ΛCDM model, where the Universe is assumed to contain normal (baryonic) matter, cold dark matter, radiation (including both photons and neutrinos), and a cosmological constant. The fractional contribution of each to the current energy density of the Universe is given by the density parameters Ωm, Ωr, and ΩΛ. The full ΛCDM model is described by a number of other parameters, but for the purpose of computing its age these three, along with the Hubble parameter H0 are the most important. Hubbles law is the statement in astronomy that the redshift in light coming from distant galaxies is proportional to their distance. ... 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. ... The accelerating universe is the observation that the universe appears to be expanding at an accelerated rate. ... This article is about the cosmological theory. ... Image File history File links Download high-resolution version (930x858, 62 KB) A plot of the age of the universe as a function of some important cosmological parameters. ... Image File history File links Download high-resolution version (930x858, 62 KB) A plot of the age of the universe as a function of some important cosmological parameters. ... A pie chart indicating the proportional composition of different energy-density components of the universe. ... A pie chart indicating the proportional composition of different energy-density components of the universe. ... For other uses, see Dark matter (disambiguation). ... In modern physics the photon is the elementary particle responsible for electromagnetic phenomena. ... For other uses, see Neutrino (disambiguation). ... In physical cosmology, the cosmological constant (usually denoted by the Greek capital letter lambda: Λ) was proposed by Albert Einstein as a modification of his original theory of general relativity to achieve a stationary universe. ... Alexander Friedmann The Friedmann equations are a set of equations in cosmology that govern the expansion of space in homogeneous and isotropic models of the universe within the context of general relativity. ... A pie chart indicating the proportional composition of different energy-density components of the universe. ... Hubbles law is the statement in astronomy that the redshift in light coming from distant galaxies is proportional to their distance. ...


If one has accurate measurements of these parameters, then the age of the universe can be determined by using the Friedmann equation. This equation relates the rate of change in the scale factor a(t) to the matter content of the Universe. Turning this relation around, we can calculate the change in time per change in scale factor and thus calculate the total age of the universe by integrating this formula. The age t0 is then given by an expression of the form, where the function F() depends only on the fractional contribution to the Universe's energy content that comes from various components. The first observation that one can make from this formula is that it is the Hubble parameter that controls that age of the universe, with a correction arising from the matter and energy content. So a rough estimate of the age of the universe comes from the inverse of the Hubble parameter, The Friedmann equations relate various cosmological parameters within the context of general relativity. ... A scale factor is a number which scales, or multiplies, some quantity. ... This article is about the concept of integrals in calculus. ...


To get a more accurate number, the correction factor F() must be computed. In general this must be done numerically, and the results for a range of cosmological parameter values are shown in the figure. For the WMAP values (Ωm,ΩΛ) = (0.266,0.732), shown by the box in the upper left corner of the figure, this correction factor is nearly one: F = 0.996. For a flat universe without any cosmological constant, shown by the star in the lower right corner, F = 2 / 3 is much smaller and thus the universe is younger for a fixed value of the Hubble parameter. To make this figure, Ωr is held constant (roughly equivalent to holding the CMB temperature constant) and the curvature density parameter is fixed by the value of the other three. A pie chart indicating the proportional composition of different energy-density components of the universe. ... WMAP image of the CMB anisotropy,Cosmic microwave background radiation(June 2003) The cosmic microwave background radiation (CMB) is a form of electromagnetic radiation that fills the whole of the universe. ...


The Wilkinson Microwave Anisotropy Probe (WMAP) was instrumental in establishing an accurate age of the Universe, though other measurements must be folded in to gain an accurate number. CMB measurements are very good at constraining the matter content Ωm [3] and curvature parameter Ωk .[4] It is not as sensitive to ΩΛ directly,[4] partly because the cosmological constant only becomes important at low redshift. The most accurate determinations of the Hubble parameter H0 come from Type Ia supernovae. Combining these measurements leads to the generally accepted value for the age of the universe quoted above. 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. ... WMAP image of the CMB anisotropy,Cosmic microwave background radiation(June 2003) The cosmic microwave background radiation (CMB) is a form of electromagnetic radiation that fills the whole of the universe. ... Multiwavelength X-ray image of the remnant of Keplers Supernova, SN 1604. ...


The cosmological constant makes the universe "older" for fixed values of the other parameters. This is significant, since before the cosmological constant became generally accepted, the Big Bang model had difficulty explaining why globular clusters in the Milky Way appeared to be far older than the age of the universe as calculated from the Hubble parameter and a matter-only universe.[5][6] Introducing the cosmological constant allows the universe to be older than these clusters, as well as explaining other features that the matter-only cosmological model could not.[7] The Globular Cluster M80 in the constellation Scorpius is located about 28,000 light years from the Sun and contains hundreds of thousands of stars. ...


Age based on WMAP

NASA's Wilkinson Microwave Anisotropy Probe (WMAP) project estimates the age of the universe to be: For other uses, see NASA (disambiguation). ... 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. ...

(13.73 ± 0.12) × 109 years.

That is, the universe is about 13.73 billion years old,[1] with an uncertainty of 120 million years. However, this age is based on the assumption that the project's underlying model is correct; other methods of estimating the age of the universe could give different ages. Assuming an extra background of relativistic particles, for example, can enlarge the error bars of the WMAP constraint by one order of magnitude.[8] One thousand million (1,000,000,000) is the natural number following 999,999,999 and preceding 1,000,000,001. ... A year (from Old English gēr) is the time between two recurrences of an event related to the orbit of the Earth around the Sun. ... Look up million in Wiktionary, the free dictionary. ...


This measurement is made by using the location of the first acoustic peak in the microwave background power spectrum to determine the size of the decoupling surface (size of universe at the time of recombination). The light travel time to this surface (depending on the geometry used) yields a reliable age for the universe. Assuming the validity of the models used to determine this age, the residual accuracy yields a margin of error near one percent.[9] CMB redirects here. ...


This is the value currently most quoted by astronomers.


Assumption of strong priors

Calculating the age of the universe is only accurate if the assumptions built into the models being used to estimate it are also accurate. This is referred to as strong priors and essentially involves stripping the potential errors in other parts of the model to render the accuracy of actual observational data directly into the concluded result. Although this is not a valid procedure in all contexts (as noted in the accompanying caveat: "based on the fact we have assumed the underlying model we used is correct"), the age given is thus accurate to the specified error (since this error represents the error in the instrument used to gather the raw data input into the model). A preceding assumption, theory, concept or idea upon which a current assumption, theory, concept or idea is founded on. ...


The age of the universe based on the "best fit" to WMAP data "only" is 13.69±0.13 Gyr[1] (the slightly higher number of 13.73 includes some other data mixed in). This number represents the first accurate "direct" measurement of the age of the universe (other methods typically involve Hubble's law and age of the oldest stars in globular clusters, etc). It is possible to use different methods for determining the same parameter (in this case – the age of the universe) and arrive at different answers with no overlap in the "errors". To best avoid the problem, it is common to show two sets of uncertainties; one related to the actual measurement and the other related to the systematic errors of the model being used. This box:      Hubbles law is a statement in physical cosmology which states that the redshift in light coming from distant galaxies is proportional to their distance. ...


An important component to the analysis of data used to determine the age of the universe (e.g. from WMAP) therefore is to use a Bayesian Statistical analysis, which normalizes the results based upon the priors (i.e. the model).[9] This quantifies any uncertainty in the accuracy of a measurement due to a particular model used.[10][11] 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. ... Bayesian inference is statistical inference in which probabilities are interpreted not as frequencies or proportions or the like, but rather as degrees of belief. ...


References

  1. ^ a b c Five-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Data Processing, Sky Maps, and Basic Results. nasa.gov. Retrieved on 2008-03-06.
  2. ^ Common Misconceptions About the Big Bang .. talkorigins.org. Retrieved on 2008-03-29.
  3. ^ Animation: Matter Content Sensitivity. The matter-radiation ratio is raised while keeping all other parameters fixed (Omega_0h^2= 0.1-1) .. uchicago.edu. Retrieved on 2008-02-23.
  4. ^ a b Animation:Angular diameter distance scaling with curvature and lambda (Omega_K=1-Omega_0-Omega_Lambda, fixed Omega_0h^2 and Omega_Bh^2). uchicago.edu. Retrieved on 2008-02-23.
  5. ^ Globular Star Clusters. seds.org. Retrieved on 2008-02-23.
  6. ^ Independent age estimates. astro.ubc.ca. Retrieved on 2008-02-23.
  7. ^ J. P. Ostriker; Paul J. Steinhardt. "COSMIC CONCORDANCE". Retrieved on 2008-02-23.
  8. ^ Francesco de Bernardis; A. Melchiorri, L. Verde, R. Jimenez. "The Cosmic Neutrino Background and the age of the Universe". Retrieved on 2008-02-23.
  9. ^ a b Spergel, D. N.; et al. (2003). "First-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Determination of Cosmological Parameters". The Astrophysical Journal Supplement Series 148: 175—194. doi:10.1086/377226. 
  10. ^ Loredo, T. J.. "The Promise of Bayesian Inference for Astrophysics" (PDF). Retrieved on 2008-02-23.
  11. ^ Colistete, R.; J. C. Fabris & S. V. B. Concalves (2005). "Bayesian Statistics and Parameter Constraints on the Generalized Chaplygin Gas Model Using SNe ia Data". International Journal of Modern Physics D 14 (5): 775—796. arXiv:astro-ph/0409245. Retrieved on 2008-02-23. 

2008 (MMVIII) is the current year, a leap year that started on Tuesday of the Anno Domini (or common era), in accordance to the Gregorian calendar. ... is the 65th day of the year (66th in leap years) in the Gregorian calendar. ... 2008 (MMVIII) is the current year, a leap year that started on Tuesday of the Anno Domini (or common era), in accordance to the Gregorian calendar. ... is the 88th day of the year (89th in leap years) in the Gregorian calendar. ... 2008 (MMVIII) is the current year, a leap year that started on Tuesday of the Anno Domini (or common era), in accordance to the Gregorian calendar. ... is the 54th day of the year in the Gregorian calendar. ... 2008 (MMVIII) is the current year, a leap year that started on Tuesday of the Anno Domini (or common era), in accordance to the Gregorian calendar. ... is the 54th day of the year in the Gregorian calendar. ... 2008 (MMVIII) is the current year, a leap year that started on Tuesday of the Anno Domini (or common era), in accordance to the Gregorian calendar. ... is the 54th day of the year in the Gregorian calendar. ... 2008 (MMVIII) is the current year, a leap year that started on Tuesday of the Anno Domini (or common era), in accordance to the Gregorian calendar. ... is the 54th day of the year in the Gregorian calendar. ... 2008 (MMVIII) is the current year, a leap year that started on Tuesday of the Anno Domini (or common era), in accordance to the Gregorian calendar. ... is the 54th day of the year in the Gregorian calendar. ... 2008 (MMVIII) is the current year, a leap year that started on Tuesday of the Anno Domini (or common era), in accordance to the Gregorian calendar. ... is the 54th day of the year in the Gregorian calendar. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... PDF is an abbreviation with several meanings: Portable Document Format Post-doctoral fellowship Probability density function There also is an electronic design automation company named PDF Solutions. ... 2008 (MMVIII) is the current year, a leap year that started on Tuesday of the Anno Domini (or common era), in accordance to the Gregorian calendar. ... is the 54th day of the year in the Gregorian calendar. ... arXiv (pronounced archive, as if the X were the Greek letter χ) is an archive for electronic preprints of scientific papers in the fields of physics, mathematics, computer science and quantitative biology which can be accessed via the Internet. ... 2008 (MMVIII) is the current year, a leap year that started on Tuesday of the Anno Domini (or common era), in accordance to the Gregorian calendar. ... is the 54th day of the year in the Gregorian calendar. ...

External links

  • Ned Wright's Cosmology Tutorial
  • Wright, Edward L. (2 July 2005). Age of the Universe.
  • Wayne Hu's cosmological parameter animations
  • J. P. Ostriker and P. J. Steinhardt, Cosmic Concordance, arXiv:astro-ph/9505066.
  • SEDS page on "Globular Star Clusters"
  • Douglas Scott "Independent Age Estimates"
  • KryssTal "The Scale of the Universe" Space and Time scaled for the beginner.
is the 183rd day of the year (184th in leap years) in the Gregorian calendar. ... Year 2005 (MMV) was a common year starting on Saturday (link displays full calendar) of the Gregorian calendar. ... Jeremiah (Jerry) Paul Ostriker (b. ... Paul J. Steinhardt is the Albert Einstein Professor of Science at Princeton University and a professor of theoretical physics. ...

  Results from FactBites:
 
The Age of the Universe is a Function of Time (1242 words)
The estimated age of the universe as a function of the time the estimate was made.
This should not be surprising, considering that early estimates of the age of the earth were largely guesswork based on poor methodology, while the more recent estimates of the age of the universe are scientific guesswork based on advanced techniques and instrumentation.
If these age estimates are to be taken seriously one cannot escape the conclusion that as time goes on the age of universe not only increases, but does so at an accelerating rate.
The Age of the Universe (3957 words)
Note that this age is not exactly equal to the age of the star itself; it is essentially the "mean age" of the supernovae that formed it, which themselves may not have happened all at the same time either.
And while any given white dwarf may be relatively young and therefore not a useful constraint on the age of the universe, since white dwarfs are permanent objects, for a sufficiently large sample, in a large enough sample we should expect at least a few the oldest white dwarfs should originate from the earliest stars.
This age difference is due to the varying ages at which the white dwarfs actually emerge from their progenitor stars: the hotter, "younger" dwarfs came from longer-lived stars (see Figure 8).
  More results at FactBites »

 
 

COMMENTARY     


Share your thoughts, questions and commentary here
Your name
Your comments

Want to know more?
Search encyclopedia, statistics and forums:

 


Press Releases |  Feeds | Contact
The Wikipedia article included on this page is licensed under the GFDL.
Images may be subject to relevant owners' copyright.
All other elements are (c) copyright NationMaster.com 2003-5. All Rights Reserved.
Usage implies agreement with terms, 1022, m