Editing Intergalactic travel (section)

===Hypervelocity stars===
{{see also|Intergalactic star}}
Theorized in 1988,<ref>{{cite journal
 | first = J. G. | last = Hills | title = Hyper-velocity and tidal stars from binaries disrupted by a massive Galactic black hole | journal = Nature | year = 1988 | volume = 331
 | issue = 6158
 | pages = 687–689 | bibcode = 1988Natur.331..687H
 | doi = 10.1038/331687a0 | s2cid = 4250308 | url = https://zenodo.org/record/1233107 | url-access =  | url-status =  | archive-url =  | archive-date =  }}</ref> and observed in 2005,<ref name='HVS1'>{{cite journal
 | first = Warren R. | last = Brown |author2=Geller, Margaret J. |author3=Kenyon, Scott J. |author4=Kurtz, Michael J.
 | title = Discovery of an Unbound Hypervelocity Star in the Milky Way Halo | journal = Astrophysical Journal | year = 2005
 | volume = 622
 | issue = 1 | pages = L33–L36 | bibcode = 2005ApJ...622L..33B
 | doi = 10.1086/429378 |arxiv = astro-ph/0501177 | s2cid = 14322324 }}</ref> [[hypervelocity stars]] move faster than the [[escape velocity]] of the Milky Way, and are traveling out into intergalactic space.<ref>{{cite news| url=http://hvsproject.blogspot.com/2009/09/hyper-velocity-star-project.html
| title=The Hyper Velocity Star Project: The stars| publisher=The Hyper-Velocity Star Project| date=6 September 2009| access-date=20 September 2014}}</ref> There are several [[Stellar kinematics#Origin of hypervelocity stars|theories for their existence]]. One of the mechanisms would be that the [[supermassive black hole]] at the center of the [[Milky Way]] ejects some stars from the galaxy at a rate of about one every hundred thousand years. Another theorized mechanism might be a supernova explosion in a binary system.<ref>{{cite news
  | url=http://newswise.com/articles/view/535733/
  | title=Chandra discovers cosmic cannonball
  | first=Megan | last=Watzke | date= 28 November 2007
  | publisher=Newswise }}</ref> Intergalactic travel using these stars would involve entering into an orbit around them and waiting for them to reach another galaxy.<ref>{{cite news| url=http://news.discovery.com/space/the-great-escape-intergalactic-travel-is-possible.html| title=The Great Escape: Intergalactic Travel is Possible| author=Villard, Ray| date=24 May 2010| publisher=Discovery News| access-date=October 18, 2010| archive-date=14 November 2012| archive-url=https://web.archive.org/web/20121114090512/http://news.discovery.com/space/the-great-escape-intergalactic-travel-is-possible.html| url-status=dead}}</ref><ref>{{cite news | author= Gilster, Paul | date= 26 June 2014 | url= http://www.centauri-dreams.org/?p=30936 | title= Intergalactic Travel via Hypervelocity Stars | website= centauri-dreams.org | access-date= 16 September 2014}}</ref>