Editing Orbit (section)

==Strange orbits==
Mathematicians have discovered that it is possible in principle to have multiple bodies in non-elliptical orbits that repeat periodically, although most such orbits are not stable regarding small perturbations in mass, position, or velocity. However, some special stable cases have been identified, including a planar figure-eight orbit occupied by [[Three-body problem|three moving bodies]].<ref>{{Cite arXiv|last1=Chenciner|first1=Alain|last2=Montgomery|first2=Richard|date=2000-10-31|title=A remarkable periodic solution of the three-body problem in the case of equal masses|eprint=math/0011268}}</ref> Further studies have discovered that nonplanar orbits are also possible, including one involving 12 masses moving in 4 roughly circular, interlocking orbits [[topology|topologically]] equivalent to the edges of a [[cuboctahedron]].<ref name="Peterson">{{cite web|last1=Peterson|first1=Ivars|title=Strange Orbits|url=https://www.sciencenews.org/article/strange-orbits-1|website=Science News|language=en|date=23 September 2013|access-date=21 July 2017|archive-date=22 November 2015|archive-url=https://web.archive.org/web/20151122231340/https://www.sciencenews.org/article/strange-orbits-1|url-status=live}}</ref>

Finding such orbits naturally occurring in the universe is thought to be extremely unlikely, because of the improbability of the required conditions occurring by chance.<ref name="Peterson" />