Difference between revisions 7633735 and 7633764 on simplewiki

{{inuse}}
{{short description|Scientific projections regarding the far future}}
[[File:Red Giant Earth warm.jpg|thumb|274x274px|alt= A dark gray and red sphere representing the Earth lies against a black background to the right of an orange circular object representing the Sun| Artist's idea of the [[Earth]] several billion years from now, when the [[Sun]] is a [[red giant]].]]

The ultimate fate of our universe may be the [[heat death of the universe]]. Before that happens, it is possible to predict that the following will happen.

Some types of [[science]] can say what could happen far into the future.<ref>{{cite book| author= Rescher, Nicholas|  title = Predicting the future: An introduction to the theory of forecasting| date = 1998| publisher = State University of New York Press| isbn = 978-0791435533}}</ref> Before we go further, it is worth noting that our [[local group|local group of galaxies]] are bound by gravitation, and its changes and aging can be discussed separate from the rest of the universe.

For example, [[astrophysics]] can say how [[planet]]s and [[star]]s form, affect each other, and die; [[particle physics]] can say how [[atom]]s and other matter act over time; [[evolutionary biology]] can allow us to see how living things change over time; and [[plate tectonics]] can say how continents shift over time.  By observing the past and present, astrophysicists, particle physicists, evolutionary biologists and geologists can make good guesses about what might happen in the future.  We call these guesses ''predictions''.

The [[second law of thermodynamics]] is important to predictions about the [[future of Earth]], [[Future, of the Solar System|the Solar System]], and [[Fthe future of anthe expanding universe|the [[universe]]. The second law of thermodynamics says that [[entropy]] is always happening.  That means that the universe is slowly running out of the kind of energy that can do [[work (physics)|work]].<ref name="Nave"/> For example, stars will eventually run out of [[hydrogen]] fuel and burn out.<ref name="five ages"/>

Physicists believe that most [[matter]], which is anything that has mass and takes up space, will eventually break apart because of [[radioactive decay]]. Even the most stable molecules and atoms will break into subatomic particles.<ref name="dying"/> Scientists do believe the [[Flat universe|universe is flat]] (or almost flat), so it will not [[Big Crunch|collapse in on itself]] after a finite time.<ref name="Komatsu"/> But if there really is an infinite amount of time, then even very unlikely events might happen, such as the formation of [[Boltzmann brain]]s.<ref name="linde"/>

This article shows timelines from the beginning of the 4th millennium (3001 CE) into the far, far future. It discusses whether [[Human extinction|humans will become extinct]], whether [[protons decay]], and whether the Earth will still exist when the Sun expands to become a [[red giant]].⏎
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==<span id=Legend>Key</span>==

{| class="wikitable"
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| style="background: lavender;" | [[File:Five Pointed Star Solid.svg|16px|alt=Astronomy and astrophysics|Astronomy and astrophysics]]
| [[Astronomy]] and [[astrophysics]]
|-
| style="background: #f0dc82;" | [[File:Noun project 528.svg|16px|alt=Geology and planetary science|Geology and planetary science]]
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| style="background: lavender;" | [[File:Five Pointed Star Solid.svg|16px|alt=Astronomy and astrophysics|Astronomy and astrophysics]]
| 22 billion

| The end of the Universe in the [[Big Rip]] scenario, assuming a model of [[dark energy]] with [[Equation of state (cosmology)|{{var|w}} = −1.5]].<ref name="bigrip"/> If the density of [[dark energy]] is less than −1, then the [[Universe's expansion]] will continue to happen faster and faster and the [[Observable Universe]] will continue to shrink. Around 200 million years before the Big Rip, galaxy clusters like the [[Local Group]] or the [[Sculptor Group]] will be destroyed. Sixty million years before the Big Rip, all galaxies will begin to lose stars around their edges and will completely disintegrate in another 40 million years. Three months before the Big Rip, all star systems will become gravitationally unbound, and planets will fly off into the rapidly expanding universe. Thirty minutes before the Big Rip, [[planet]]s, [[star]]s, [[asteroid]]s and even extreme objects like [[neutron star]]s and [[black hole]]s will evaporate into [[atom]]s. One hundred [[zeptosecond]]s (10<sup>−19</sup> seconds) before the Big Rip, atoms would break apart. Ultimately, once rip reaches the [[Planck scale]], cosmic strings will be disintegrated and so will the fabric of [[spacetime]] itself. The universe will enter into a "rip singularity" when all distances become infinitely large. However, in a very different prediction, a "crunch singularity" all matter is infinitely packed together tightly. In a "rip singularity" all matter is infinitely spread out.<ref>{{cite journal
| doi = 10.1103/PhysRevLett.91.071301
| last = Caldwell | first = Robert R. |author2=Kamionkowski, Marc |author3=Weinberg, Nevin N.
| title = Phantom Energy and Cosmic Doomsday
| journal = Physical Review Letters
| volume = 91
| pages = 071301
| year = 2003
| pmid=12935004
| arxiv=astro-ph/0302506
| bibcode=2003PhRvL..91g1301C
| issue = 7
}}</ref> However, observations of [[galaxy cluster]] speeds by the [[Chandra X-ray Observatory]] suggest that the true value of {{var|w}} is c. −0.991, meaning the Big Rip will not happen.<ref name="chand"/>
|-
| style="background: lavender;" | [[File:Five Pointed Star Solid.svg|16px|alt=Astronomy and astrophysics|Astronomy and astrophysics]]⏎
| 50 billion
| If the Earth and Moon are not engulfed by the Sun, by this time they will become [[Tidal locking|tidally locked]], with each showing only one face to the other so that there is no day or night.<ref name="tide1">
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<ref name=loeb_2016>{{cite journal |last1=Loeb |first1=Abraham |year=2016 |last2=Batista |first2=Rafael |last3=Sloan |first3=W. |title=Relative Likelihood for Life as a Function of Cosmic Time |journal=Journal of Cosmology and Astroparticle Physics |volume=2016 |issue=8 |pages=040 | arxiv = 1606.08448 |doi=10.1088/1475-7516/2016/08/040|bibcode=2016JCAP...08..040L }}</ref>

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{{Millennia}}

[[Category:Time]]
[[Category:Science]]