Content deleted Content added
Tags: Reverted Mobile edit Mobile web edit |
Replace template per TfD |
||
| (3 intermediate revisions by 2 users not shown) | |||
Line 6:
[[File:Apogee (PSF) mul.svg|lang=zxx|thumb|345px|The apsides refer to the farthest (2) and nearest (3) points reached by an orbiting [[planetary-mass object|planetary body]] (2 and 3) with respect to a [[primary body|primary, or host, body]] (1)]]
An '''apsis''' ({{etymology|grc|''{{
Apsides pertaining to orbits around the [[Sun]] have distinct names to differentiate themselves from other apsides; these names are '''''aphelion''''' for the farthest and '''''perihelion''''' for the nearest point in the solar orbit.<ref>{{Cite web |author1=Joe Rao |date=2023-07-06 |title=Happy Aphelion Day! Earth is at its farthest from the sun for 2023 today |url=https://www.space.com/earth-farthest-from-sun-aphelion-july-2023 |access-date=2024-04-22 |website=Space.com |language=en}}</ref> The [[Moon]]'s two apsides are the farthest point, '''''apogee''''', and the nearest point, '''''perigee''''', of its orbit around the host [[Earth]]. Earth's two apsides are the farthest point, ''aphelion'', and the nearest point, ''perihelion'', of its orbit around the host Sun. The terms ''aphelion'' and ''perihelion'' apply in the same way to the orbits of [[Jupiter]] and the other [[planet]]s, the [[comet]]s, and the [[asteroid]]s of the [[Solar System]].
Line 38:
Various related terms are used for other [[Celestial body|celestial objects]]. The suffixes ''-gee'', ''-helion'', ''-astron'' and ''-galacticon'' are frequently used in the astronomical literature when referring to the Earth, Sun, stars, and the [[Galactic Center]] respectively. The suffix ''-jove'' is occasionally used for Jupiter, but ''-saturnium'' has very rarely been used in the last 50 years for Saturn. The ''-gee'' form is also used as a generic closest-approach-to "any planet" term—instead of applying it only to Earth.
During the [[Apollo program]], the terms ''pericynthion'' and ''apocynthion'' were used when referring to [[lunar orbit|orbiting the Moon]]; they reference Cynthia, an alternative name for the Greek Moon goddess [[Artemis]].<ref>{{cite web | title = Apollo 15 Mission Report | work = Glossary | url = https://history.nasa.gov/alsj/a15/a15mr-f.htm | access-date = October 16, 2009 | archive-date = March 19, 2010 | archive-url = https://web.archive.org/web/20100319081116/http://history.nasa.gov/alsj/a15/a15mr-f.htm | url-status = live }}</ref> More recently, during the [[Artemis program]], the terms ''perilune'' and ''apolune'' have been used.<ref>{{cite conference |author=R. Dendy |author2=D. Zeleznikar |author3=M. Zemba | title = NASA Lunar Exploration – Gateway's Power and Propulsion Element Communications Links | conference = 38th International Communications Satellite Systems Conference (ICSSC) | date = September 27, 2021 | location = Arlington, VA | url = https://ntrs.nasa.gov/citations/20210019019 | access-date = July 18, 2022 | archive-date = Mar 29, 2022 | archive-url=https://web.archive.org/web/20220329140256/https://ntrs.nasa.gov/citations/20210019019 | url-status = live }}</ref>
Regarding black holes, the term peribothron was first used in a 1976 paper by J. Frank and M. J. Rees,<ref>{{cite journal |author1=Frank, J. |author2=Rees, M.J. |title=Effects of massive black holes on dense stellar systems. |journal=MNRAS |volume=176 |pages=633–646 |date=September 1, 1976 |issue=6908 |doi=10.1093/mnras/176.3.633|bibcode=1976MNRAS.176..633F|doi-access=free }}</ref> who credit W. R. Stoeger for suggesting creating a term using the greek word for pit: "bothron".
Line 128:
[[File:Perihelion-Aphelion.svg|thumb|Diagram of a body's direct [[orbit]] around the [[Sun]] with its nearest (perihelion) and farthest (aphelion) points]]
The perihelion (q) and aphelion (Q) are the nearest and
Comparing [[osculating elements]] at a specific [[Epoch (astronomy)|epoch]] to effectively those at a different epoch will generate differences. The time-of-perihelion-passage as one of six osculating elements is not an exact prediction (other than for a generic [[Two-body problem|two-body model]]) of the actual minimum distance to the Sun using the [[n-body problem|full dynamical model]]. Precise predictions of perihelion passage require [[numerical integration]].
| |||