The heat death of the universe
Hypothesis that the universe will reach maximum entropy.
Last updated
The heat death hypothesis describes a future state where the universe reaches maximum entropy and can no longer sustain thermodynamic processes.[1] If the universe is flat or open and continues expanding, a heat death is expected to occur after a very long period of cooling.[2] The idea was first proposed in loose terms by Lord Kelvin in 1851, building on earlier work by Carnot, Joule, and Clausius.[3]
Quick Facts
- Field
- Cosmology, Thermodynamics
- Known for
- Hypothesis of the heat death of the universe, heat death paradox
- Key proponent
- Lord Kelvin (William Thomson)
- Related figures
- Jean Sylvain Bailly
- Hermann von Helmholtz
- William Rankine
- Basis
- Second law of thermodynamics
Facts from the source article.
Key facts and history
French astronomer Jean Sylvain Bailly in 1777 suggested that all planets cool off, eventually becoming too cold to support life.[4] Kelvin's 1862 paper "On the age of the Sun's heat" reiterated his beliefs in the indestructibility of energy and the universal dissipation of energy.[3] The decay time for a supermassive black hole of roughly one galaxy mass due to Hawking radiation is on the order of 10^100 years.[5] After black holes evaporate, the universe enters the Dark Era, consisting chiefly of a dilute gas of photons and leptons.[6]
After Thomson's 1852 and 1862 papers, both Helmholtz and Rankine acknowledged Thomson as the originator of the idea and released their own writings claiming the universe would conclude in a "heat death" (Helmholtz) or the "end of all physical phenomena" (Rankine).[7] With a positive cosmological constant, the universe will asymptotically reach a maximum entropy condition where no work can be performed.[8]
What the cited sources add
The 19th-century founders of thermodynamics realized that the same principles of heat death apply to the universe as a whole.[9] Hermann von Helmholtz wrote in 1854 that the universe would be "condemned to a state of eternal rest".[9] Physicists have recently been thinking that a supposedly heat-dead universe is more interesting than it looks.[9] An investigation into why has led researchers to reconsider how things in general evolve, including the universe itself.[9]
Gradually emerging from this work is a picture of the full life cycle of quantum systems, including the universe as a whole.[9] Science tells us the universe is expanding, the Sun will eventually burn out, and our world will end billions of years from now in a cold nothingness.[10] WMAP data determined that dark energy, in the form of a cosmological constant, makes up about 70% of the universe, causing the expansion rate to speed up.[11]
References
- Wikipedia, "Heat death of the universe" (CC BY-SA 4.0), which cites: WMAP – Fate of the Universe, WMAP's Universe, NASA. Accessed online July 17, 2008.; Dyer, "Insiders: Space", Simon & Schuster Books for Young Readers, 2007-07-24, p. 40–41 (we also read that source) en.wikipedia.org
- Wikipedia, "Heat death of the universe" (CC BY-SA 4.0), which cites: Plait, "Death from the Skies!", Viking Adult, 2008, p. 259 (we also read that source) en.wikipedia.org
- Wikipedia, "Heat death of the universe" (CC BY-SA 4.0), which cites: Smith, "Energy and Empire: A Biographical Study of Lord Kelvin", Cambridge University Press, 1989, p. 500 (we also read that source) en.wikipedia.org
- Wikipedia, "Heat death of the universe" (CC BY-SA 4.0), which cites: Brush, "A History of Modern Planetary Physics: Nebulous Earth", Cambridge University Press, 1996, p. 77 (we also read that source) en.wikipedia.org
- Wikipedia, "Heat death of the universe" (CC BY-SA 4.0), which cites: Adams, "A dying universe: the long-term fate and evolution of astrophysical objects", Reviews of Modern Physics, 1997, p. 337–72; Page, "Particle emission rates from a black hole: Massless particles from an uncharged, nonrotating hole", Physical Review D, 15 January 1976, p. 198–206 (original not read by us) en.wikipedia.org
- Wikipedia, "Heat death of the universe" (CC BY-SA 4.0), which cites: Frautschi, "Entropy in an Expanding Universe", Science, 13 August 1982, p. 593–9; Adams, "A dying universe: the long-term fate and evolution of astrophysical objects", Reviews of Modern Physics, 1997, p. 337–72 (original not read by us) en.wikipedia.org
- Wikipedia, "Heat death of the universe" (CC BY-SA 4.0), which cites: Smith, "Energy and Empire: A Biographical Study of Lord Kelvin", Cambridge University Press, 1989, p. 500; "Physics Chronology" (we also read that source) en.wikipedia.org
- Wikipedia, "Heat death of the universe" (CC BY-SA 4.0), which cites: Dyson, "Disturbing Implications of a Cosmological Constant", Journal of High Energy Physics, 12 November 2002, p. 011 (original not read by us) en.wikipedia.org
- Musser, "In New Paradox, Black Holes Appear to Evade Heat Death", Quanta Magazine, 6 June 2023. facts only, no text reused. quantamagazine.org
- Consolmagno, "Heaven or Heat Death?", Thinking Faith, 2008-05-08. facts only, no text reused. thinkingfaith.org
- WMAP – Fate of the Universe, WMAP's Universe, NASA. Accessed online July 17, 2008.. facts only, no text reused. map.gsfc.nasa.gov
Each numbered sentence above was checked against the source it cites before publication. Sentences citing Wikipedia adapt text from the English Wikipedia article Heat death of the universe (contributors), used under CC BY-SA 4.0; this entry is available under the same licence. Other sources were used for facts only; no text or images are copied from them.
More in Cosmic Mysteries
Sources
Compiled from Wikipedia and the sources listed below. Text from Wikipedia is available under CC BY-SA 4.0; this entry is adapted from it.
- Wikipedia: Heat death of the universe (CC BY-SA 4.0).
Spotted an error? Know more?
Reader corrections go straight into our review queue. Suggest an edit · How this site is sourced