1 E19 s and more

To help compare orders of magnitude of different times, this page lists times longer than 10¹⁹ seconds (317 billion years). See also "Heat death of the universe".

Some radioisotopes have extremely long half-lives:
*(1.4 ± 0.4) × 10¹⁷ years – vanadium-50
*(1.9 ± 0.2) × 10¹⁹ years – bismuth-209
*(3.1 ± 0.4) × 10¹⁹ years – cadmium-116
*(2.2 ± 0.3) × 10²⁴ years – tellurium-128

The following times all assume that the Universe is "open"; that is to say that it will continue indefinitely and not collapse in upon itself within a finite timescale.

* 10¹² (1 trillion) years—low estimate for the time until star formation ends in galaxies as galaxies are depleted of the gas clouds they need to form stars.A dying universe: the long-term fate and evolution of astrophysical objects, Fred C. Adams and Gregory Laughlin, "Reviews of Modern Physics" 69, #2 (April 1997), pp. 337–372. bibcode|1997RvMP...69..337A. doi|10.1103/RevModPhys.69.337. arxiv|astro-ph|9701131.] ^{, §IID.}
* 2×10¹² (2 trillion years)—time until all galaxies outside the Local Supercluster are no longer detectable in any way, assuming that dark energy continues to make the Universe expand at an accelerating rate. [ [http://arxiv.org/pdf/astro-ph/9902189v1 Life, the Universe, and Nothing: Life and Death in an Ever-expanding Universe] (PDF preprint), Lawrence M. Krauss and Glenn D. Starkman, "Astrophysical Journal", 531 (March 1, 2000), pp. 22–30. doi|10.1086/308434. bibcode|2000ApJ...531...22K. arXiv|astro-ph|9902189.]
* 10¹³ (10 trillion) to 2×10¹³ (20 trillion) years—lifetime of the longest-lived stars, low-mass red dwarfs. ^§IIA.
* 10¹⁴ (100 trillion) years—high estimate for the time until star formation ends in galaxies.^{, §IID.} Once star formation ends and the least massive red dwarfs exhaust their fuel, the only stellar-mass objects remaining will be stellar remnants (white dwarfs, neutron stars and black holes.) Brown dwarfs will also remain. ^§IIE.
* 10¹⁵ years—estimated time until planets are detached from their orbits. Whenever two objects pass close to each other, the orbits of their planets can be disrupted and the planets can be ejected from orbit around their parent objects. Planets with closer orbits take longer to be ejected in this manner on average because a passing object must make a closer pass to the planet's primary to eject the planet.^{, §IIIF, Table I.}
* 10¹⁹ to 10²⁰ years—the estimated time until brown dwarfs and stellar remnants are ejected from galaxies. When two objects pass close enough to each other, they exchange orbital energy with lower-mass objects tending to gain energy. The lower-mass objects can gain enough energy in this manner through repeated encounters to be ejected from the galaxy. This process will cause the galaxy to eject the majority of its brown dwarfs and stellar remnants.^{, §IIIA;}"The Five Ages of the Universe", Fred Adams and Greg Laughlin, New York: The Free Press, 1999, ISBN 0-684-85422-8.] ^{, pp. 85–87}
* 10²⁰ years—estimated time until the Earth's orbit around the Sun decays via emission of gravitational radiation, if the Earth is neither first engulfed by the red giant Sun a few billion years from nowcite journal
first=K.-P. | last=Schröder | coauthors=Smith, Robert Connon | year=2008 | title=Distant future of the Sun and Earth revisited | doi=10.1111/j.1365-2966.2008.13022.x | journal=Monthly Notices of the Royal Astronomical Society | id=arxiv|0801.4031 | volume=386 | pages=155] cite journal | author=I. J. Sackmann, A. I. Boothroyd, K. E. Kraemer | title=Our Sun. III. Present and Future | pages=457 | journal=Astrophysical Journal | year=1993 | volume=418 | url=http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1993ApJ...418..457S | doi=10.1086/173407 ] nor ejected from its orbit by a stellar encounter before then.
* 10³² years—the smallest possible value for the proton half-life consistent with experiment. [ [http://www2.slac.stanford.edu/vvc/theory/decays.html Theory: Decays] , SLAC Virtual Visitor Center. Accessed on line June 28, 2008.]
* 3×10³⁴ years—the estimated time for all nucleons in the observable universe to decay, if the proton half-life takes its smallest possible value.Around 264 half-lives. For the worked computation with a different value of the half-life, see [http://www.nap.edu/html/oneuniverse/frontiers_solution_17.html Solution, exercise 17] , "One Universe: At Home in the Cosmos", Neil de Grasse Tyson, Charles Tsun-Chu Liu, and Robert Irion, Washington, D.C.: Joseph Henry Press, 2000. ISBN 0-309-06488-0.]
* 10⁴¹ years—the largest possible value for the proton half-life, assuming that the Big Bang was inflationary and that the same process that makes protons decay made baryons predominate over anti-baryons in the early Universe.A dying universe: the long-term fate and evolution of astrophysical objects, Fred C. Adams and Gregory Laughlin, "Reviews of Modern Physics" 69, #2 (April 1997), pp. 337–372. bibcode|1997RvMP...69..337A. doi|10.1103/RevModPhys.69.337.] ^{, §IVA.}
* 3×10⁴³ years—the estimated time for all nucleons in the observable universe to decay, if the proton half-life takes the largest possible value, 10⁴¹ years, consistent with the conditions given above.
* 10⁶⁵ years—estimated time for rigid objects like rocks to rearrange their atoms and molecules via quantum tunnelling, assuming that the proton does not decay. On this timescale all matter is liquid.
* 2×10⁶⁶ years—the estimated time until a black hole with the mass of the Sun decays by the Hawking process.Particle emission rates from a black hole: Massless particles from an uncharged, nonrotating hole, Don N. Page, "Physical Review D" 13 (1976), pp. 198–206. doi|10.1103/PhysRevD.13.198. See in particular equation (27).]
* 1.7×10¹⁰⁶ years—the estimated time until a supermassive black hole with a mass of 20 trillion solar masses decays by the Hawking process.
* 10¹⁵⁰⁰ years—the estimated time until all matter decays to ⁵⁶Fe (if the proton does not decay). See isotopes of iron.
* 10⁽¹⁰²⁶⁾ years—low estimate for the time until all matter collapses into black holes, assuming no proton decay.
* 10⁽¹⁰⁷⁶⁾ years—high estimate for the time until all matter collapses into neutron stars or black holes, again assuming no proton decay.cite journal|title=Time Without End: Physics and Biology in an open universe|author=Dyson, Freeman J. | journal=Reviews of Modern Physics | volume=51 | pages=447| year=1979| url=http://www.think-aboutit.com/Misc/time_without_end.htm |accessdate=2008-07-05 | doi=10.1103/RevModPhys.51.447 | format=HTML reprint]

*$10^\{10^\{10^\{10^\{2.08$ years—scale of an estimated Poincaré recurrence time for the quantum state of a hypothetical box containing a black hole with the mass within the presently visible region of our universe.Information Loss in Black Holes and/or Conscious Beings?, Don N. Page, "Heat Kernel Techniques and Quantum Gravity" (1995), S. A. Fulling (ed), p. 461. Discourses in Mathematics and its Applications, No. 4, Texas A&M University Department of Mathematics. arXiv|hep-th|9411193. ISBN 0963072838.] This time assumes a statistical model subject to Poincaré recurrence. A much simplified way of thinking about this time is in a model where our universe's history repeats itself arbitrarily many times due to properties of statistical mechanics, this is the time scale when it will first be somewhat similar (for a reasonable choice of "similar") to its current state again.

*$10^\{10^\{10^\{10^\{10^\{1.1\}$ years—scale of an estimated Poincaré recurrence time for the quantum state of a hypothetical box containing a black hole with the estimated mass of the entire universe, observable or not, assuming a certain inflationary model with an inflaton whose mass is 10⁻⁶ Planck masses.

See also

*Heat Death
* Second law of thermodynamics
* Big Rip
* Big Crunch
* Big Bounce
* Big Bang
* Cyclic model
* Dyson's eternal intelligence
* Final anthropic principle
* Ultimate fate of the Universe
* Graphical timeline of the Stelliferous Era
* Graphical timeline from Big Bang to Heat Death. This timeline uses the loglog scale for comparison with the graphical timeline included in this article.
*Graphical timeline of our universe. This timeline uses the more intuitive linear time, for comparison with this article.
*Timeline of the Big Bang
*Graphical timeline of the Big Bang
* The Last Question, a short story by Isaac Asimov which considers the inevitable oncome of heat death in the universe and how it may be reversed.

References

External links

* [http://www.fpx.de/fp/Fun/Googolplex/GetAGoogol.html Poincaré recurrence and large numbers]