Editing Sun (section)

===Rotation===
{{main|Solar rotation}}
The Sun rotates faster at its equator than at its [[poles of astronomical bodies|poles]]. This [[Solar rotation|differential rotation]] is caused by [[convection|convective motion]] due to heat transport and the [[Coriolis effect|Coriolis force]] due to the Sun's rotation. In a frame of reference defined by the stars, the rotational period is approximately 25.6 days at the equator and 33.5 days at the poles. Viewed from Earth as it orbits the Sun, the apparent rotational period of the Sun at its equator is about 28 days.<ref name="Phillips1995-78">{{Cite book |last=Phillips |first=K. J. H. |title=Guide to the Sun |year=1995 |publisher=[[Cambridge University Press]] |isbn=978-0-521-39788-9 |url=https://books.google.com/books?id=idwBChjVP0gC&pg=PA78 |pages=78–79}}</ref> Viewed from a vantage point above its north pole, the Sun rotates [[counterclockwise]] around its axis of spin.{{efn|name=rotation}}<ref name="spaceacademy">{{Cite web |title=The Anticlockwise Solar System |url=https://www.spaceacademy.net.au/library/notes/anticlok.htm |url-status=live |archive-url=https://web.archive.org/web/20200807081832/https://www.spaceacademy.net.au/library/notes/anticlok.htm |archive-date=7 August 2020 |access-date=2 July 2020 |publisher=Australian Space Academy}}</ref>

A survey of [[solar analog]]ues suggests the early Sun was rotating up to ten times faster than it does today. This would have made the surface much more active, with greater X-ray and UV emission. [[Sunspot]]s would have covered 5–30% of the surface.<ref>{{cite conference |title=The Sun in time: age, rotation, and magnetic activity of the Sun and solar-type stars and effects on hosted planets |last1=Guinan |first1=Edward F. |last2=Engle |first2=Scott G. |conference=The Ages of Stars, Proceedings of the International Astronomical Union, IAU Symposium |volume=258 |pages=395–408 |date=June 2009 |doi=10.1017/S1743921309032050 |arxiv=0903.4148 |bibcode=2009IAUS..258..395G}}</ref> The rotation rate was gradually slowed by [[Magnetic braking (astronomy)|magnetic braking]], as the Sun's magnetic field interacted with the outflowing [[solar wind]].<ref>{{cite journal |title=Magnetic Braking of Sun-like and Low-mass Stars: Dependence on Coronal Temperature |last1=Pantolmos |first1=George |last2=Matt |first2=Sean P. |journal=The Astrophysical Journal |volume=849 |issue=2 |at=id. 83 |date=November 2017 |doi=10.3847/1538-4357/aa9061 |doi-access=free |arxiv=1710.01340 |bibcode=2017ApJ...849...83P}}</ref> A vestige of this rapid primordial rotation still survives at the Sun's core, which rotates at a rate of once per week; four times the mean surface rotation rate.<ref>{{cite journal |title=Asymptotic g modes: Evidence for a rapid rotation of the solar core |last1=Fossat |first1=E. |last2=Boumier |first2=P. |last3=Corbard |first3=T. |last4=Provost |first4=J. |last5=Salabert |first5=D. |last6=Schmider |first6=F. X. |last7=Gabriel |first7=A. H. |last8=Grec |first8=G. |last9=Renaud |first9=C. | last10=Robillot | first10=J. M. |last11=Roca-Cortés |first11=T. |last12=Turck-Chièze |first12=S. |last13=Ulrich |first13=R. K. |last14=Lazrek |first14=M. |journal=Astronomy & Astrophysics |volume=604 |at=id. A40 |date=August 2017 |doi=10.1051/0004-6361/201730460 |arxiv=1708.00259 |bibcode=2017A&A...604A..40F}}</ref><ref>{{cite web |title=ESA, NASA's SOHO Reveals Rapidly Rotating Solar Core |first=Susannah |last=Darling |date=1 August 2017 |publisher=[[NASA]] |url=https://www.nasa.gov/science-research/heliophysics/esa-nasas-soho-reveals-rapidly-rotating-solar-core/ |access-date=31 May 2024}}</ref>