Editing Solar wind (section)

===Outer limits===
{{Main|Heliosphere}}
[[File:Transitional regions.jpg|thumb|upright=1.2|An infographic featuring the outer regions of the heliosphere based on results from the Voyager spacecraft]]
The solar wind "blows a bubble" in the [[interstellar medium]] (the rarefied hydrogen and helium gas that permeates the galaxy). The point where the solar wind's strength is no longer great enough to push back the interstellar medium is known as the [[Heliopause (astronomy)|heliopause]] and is often considered to be the outer border of the Solar System. The distance to the heliopause is not precisely known and probably depends on the current velocity of the solar wind and the local density of the interstellar medium, but it is far outside [[Pluto]]'s orbit. Scientists hope to gain perspective on the heliopause from data acquired through the [[Interstellar Boundary Explorer]] (IBEX) mission, launched in October 2008.

The heliopause is noted as one of the ways of defining the extent of the Solar System, along with the [[Kuiper belt|Kuiper Belt]] and the radius at which the Sun's gravitational influence is matched by other stars.<ref>{{Cite web|url=https://svs.gsfc.nasa.gov/12639|title=GMS: Where is the Edge of the Solar System?|website=svs.gsfc.nasa.gov|date=September 5, 2017|access-date=2019-09-22}}</ref> The maximum extent of that influence has been estimated at between 50,000 AU and 2 light-years, compared to the heliopause (the outer boundary of the heliosphere), which has been detected at about 120 AU by the ''Voyager 1'' spacecraft.<ref name="voyager.jpl.nasa.gov">{{Cite web|url=https://voyager.jpl.nasa.gov/frequently-asked-questions/|title=Voyager – Frequently Asked Questions|website=voyager.jpl.nasa.gov|language=en|access-date=2019-09-22}}</ref>

The ''[[Voyager 2]]'' spacecraft crossed the [[termination shock]] more than five times between August 30 and December 10, 2007.<ref>{{Cite web|url=https://www.nasa.gov/mission_pages/voyager/voyager-20071210.html|title=NASA – Voyager 2 Proves Solar System Is Squashed|website=www.nasa.gov|access-date=2022-07-31|archive-date=2020-04-13|archive-url=https://web.archive.org/web/20200413080741/https://www.nasa.gov/mission_pages/voyager/voyager-20071210.html|url-status=dead}}</ref> ''Voyager 2'' crossed the shock about a [[Orders of magnitude (length)|Tm]] closer to the Sun than the 13.5 Tm distance where ''[[Voyager 1]]'' came upon the termination shock.<ref>{{cite news|date=December 11, 2016|title=Voyager 2 finds solar system's shape is 'dented'|newspaper=Reuters|url=https://www.reuters.com/article/us-space-voyager-idUSN1044867120071211}}</ref><ref>{{cite web|last=Tobin|first=Kate|title=Spacecraft reaches edge of solar system – Nov. 5, 2003|url=http://edition.cnn.com/2003/TECH/space/11/05/voyager.solar.boundary/|publisher=CNN}}</ref> The spacecraft moved outward through the termination shock into the [[heliosheath]] and onward toward the [[interstellar medium]].