Editing Solar System (section)

=== Present and future ===
The Solar System remains in a relatively stable, slowly evolving state by following isolated, [[gravitationally bound]] orbits around the Sun.<ref>{{Cite journal |last1=Malhotra |first1=R. |last2=Holman |first2=Matthew |last3=Ito |first3=Takashi |date=October 2001 |title=Chaos and stability of the solar system |journal= Proceedings of the National Academy of Sciences |volume=98 |issue=22 |pages=12342–12343 |bibcode= 2001PNAS...9812342M |doi=10.1073/pnas.231384098 |pmc=60054 |pmid=11606772 |doi-access=free}}</ref> Although the Solar System has been fairly stable for billions of years, it is technically [[chaotic system|chaotic]], and may [[stability of the Solar System|eventually be disrupted]]. There is a small chance that another star will pass through the Solar System in the next few billion years. Although this could destabilize the system and eventually lead millions of years later to expulsion of planets, collisions of planets, or planets hitting the Sun, it would most likely leave the Solar System much as it is today.<ref>{{cite journal |first1=Sean |last1=Raymond |display-authors=etal |date=27 November 2023 |title=Future trajectories of the Solar System: dynamical simulations of stellar encounters within 100 au |url=https://academic.oup.com/mnras/article/527/3/6126/7452883?login=false |journal=[[Monthly Notices of the Royal Astronomical Society]] |volume=527 |issue=3 |pages=6126–6138 |arxiv=2311.12171 |bibcode=2024MNRAS.527.6126R |doi=10.1093/mnras/stad3604 |doi-access=free |access-date=10 December 2023 |archive-date=10 December 2023 |archive-url=https://web.archive.org/web/20231210152219/https://academic.oup.com/mnras/article/527/3/6126/7452883?login=false |url-status=live }}</ref>

[[File:Sun red giant.svg|thumb|The current Sun compared to its peak size in the red-giant phase]]
The Sun's main-sequence phase, from beginning to end, will last about 10&nbsp;billion years for the Sun compared to around two billion years for all other subsequent phases of the Sun's pre-[[stellar remnant|remnant]] life combined.<ref name= "mnras386_1">{{Cite journal |last1= Schröder |first1=K.-P. |last2=Connon Smith |first2=Robert |date=May 2008 |title= Distant future of the Sun and Earth revisited |journal=[[Monthly Notices of the Royal Astronomical Society]] |volume=386 |issue=1 |pages=155–163 |arxiv=0801.4031 |bibcode=2008MNRAS.386..155S |doi=10.1111/j.1365-2966.2008.13022.x |doi-access=free |s2cid=10073988}}</ref> The Solar System will remain roughly as it is known today until the hydrogen in the core of the Sun has been entirely converted to helium, which will occur roughly 5&nbsp;billion years from now. This will mark the end of the Sun's main-sequence life. At that time, the core of the Sun will contract with hydrogen fusion occurring along a shell surrounding the inert helium, and the energy output will be greater than at present. The outer layers of the Sun will expand to roughly 260 times its current diameter, and the Sun will become a [[red giant]]. Because of its increased surface area, the surface of the Sun will be cooler ({{Convert|2,600|K|F}} at its coolest) than it is on the main sequence.<ref name="mnras386_1" />

The expanding Sun is expected to vaporize Mercury as well as Venus, and render Earth and Mars uninhabitable (possibly destroying Earth as well).<ref>{{cite web | url=https://science.nasa.gov/universe/exoplanets/giant-red-stars-may-heat-frozen-worlds-into-habitable-planets/ | title=Giant red stars may heat frozen worlds into habitable planets - NASA Science | date=17 May 2016 }}</ref><ref>{{cite journal |last1= Aungwerojwit |first1=Amornrat |last2= Gänsicke |first2=Boris T |last3=Dhillon |first3=Vikram S |last4=Drake |first4= Andrew |last5=Inight |first5=Keith |last6= Kaye |first6=Thomas G |last7=Marsh |first7=T R |last8=Mullen |first8=Ed |last9= Pelisoli |first9=Ingrid |last10=Swan |first10=Andrew | display-authors = 3 |title=Long-term variability in debris transiting white dwarfs |journal=[[Monthly Notices of the Royal Astronomical Society]] |date=2024 |volume=530 |issue=1 |pages=117–128 |doi=10.1093/mnras/stae750 |doi-access=free|arxiv=2404.04422 }}</ref> Eventually, the core will be hot enough for helium fusion; the Sun will burn helium for a fraction of the time it burned hydrogen in the core. The Sun is not massive enough to commence the fusion of heavier elements, and nuclear reactions in the core will dwindle. Its outer layers will be ejected into space, leaving behind a dense [[white dwarf]], half the original mass of the Sun but only the size of Earth.<ref name="mnras386_1"/> The ejected outer layers may form a [[planetary nebula]], returning some of the material that formed the Sun—but now enriched with [[metallicity|heavier elements]] like carbon—to the [[interstellar medium]].<ref>{{Cite web|title=Planetary Nebulas|url=https://www.cfa.harvard.edu/research/topic/planetary-nebulas|access-date=6 April 2024|publisher=Harvard & Smithsonian Center for Astrophysics|website=cfa.harvard.edu|archive-date=6 April 2024|archive-url=https://web.archive.org/web/20240406205913/https://www.cfa.harvard.edu/research/topic/planetary-nebulas|url-status=live}}</ref><ref>{{Cite journal|url=https://www.nature.com/articles/s41550-018-0453-9.epdf?sharing_token=XozRTVzMDBR74HQBj2lbV9RgN0jAjWel9jnR3ZoTv0OzwWt8mLOdVW4Y_YiE39Le3Xp-8zVx5tUnLpAORu5j1mnJNZpxp_fWsbZgn60hEE3IHsu89UrtgD6uRRVi7jD74SBwEYsmB2RyB2RCfRqLbLr5EqTy1-rK2KrrLO-TxuHwLmapWXxYkuOn5Rgut4w4JuE1XKNeJeRNDNx_0juT0bPlXn9WB29_BzKx1pGlzEXtR677aZ3SUe5um8epWM4PgYT-VDXR6Jevm-M9SDszF4a2eWOeV0CdynDONJuE1n37sanK9itS1edHH_xrybrldJgWdACO4sxHnFn3DHdB0Q==|title=The mysterious age invariance of the planetary nebula luminosity function bright cut-off|first1=K.|last1=Gesicki|first2=A. A.|last2=Zijlstra|first3=M. M.|last3=Miller Bertolami|date=7 May 2018|journal=Nature Astronomy|volume=2|issue=7|pages=580–584|doi=10.1038/s41550-018-0453-9|arxiv=1805.02643|bibcode=2018NatAs...2..580G|hdl=11336/82487|s2cid=256708667|access-date=16 January 2024|archive-date=16 January 2024|archive-url=https://web.archive.org/web/20240116173409/https://www.nature.com/articles/s41550-018-0453-9.epdf?sharing_token=XozRTVzMDBR74HQBj2lbV9RgN0jAjWel9jnR3ZoTv0OzwWt8mLOdVW4Y_YiE39Le3Xp-8zVx5tUnLpAORu5j1mnJNZpxp_fWsbZgn60hEE3IHsu89UrtgD6uRRVi7jD74SBwEYsmB2RyB2RCfRqLbLr5EqTy1-rK2KrrLO-TxuHwLmapWXxYkuOn5Rgut4w4JuE1XKNeJeRNDNx_0juT0bPlXn9WB29_BzKx1pGlzEXtR677aZ3SUe5um8epWM4PgYT-VDXR6Jevm-M9SDszF4a2eWOeV0CdynDONJuE1n37sanK9itS1edHH_xrybrldJgWdACO4sxHnFn3DHdB0Q==|url-status=live}}</ref>