Editing Orbit (section)

===Relativistic orbital motion===
The above classical ([[classical mechanics|Newtonian]]) analysis of [[orbital mechanics]] assumes that the more subtle effects of [[general relativity]], such as [[frame dragging]] and [[gravitational time dilation]] are negligible. Relativistic effects cease to be negligible when near very massive bodies (as with the [[Kepler problem in general relativity|precession of Mercury's orbit]] about the Sun), or when extreme precision is needed (as with calculations of the [[orbital elements]] and time signal references for [[Global Positioning System#Relativity|GPS]] satellites.<ref>Pogge, Richard W.; [http://www.astronomy.ohio-state.edu/~pogge/Ast162/Unit5/gps.html "Real-World Relativity: The GPS Navigation System"] {{Webarchive|url=https://web.archive.org/web/20151114135709/http://www.astronomy.ohio-state.edu/~pogge/Ast162/Unit5/gps.html |date=14 November 2015 }}. Retrieved 25 January 2008.</ref>).