Editing Apparent retrograde motion (section)

{{short description|Apparent backward motion of a planet}}
{{About|the apparent motion of planets as observed from a particular vantage point|retrograde motions of celestial bodies relative to a gravitationally central object|Retrograde and prograde motion}}

[[File:The astronomical explanation for Mercury retrograde.webm|thumb|upright=1.5|thumbtime=24|An animation explaining why the planet [[Mercury (planet)|Mercury]] may appear to move "backwards", or retrograde across Earth's sky]]

'''Apparent retrograde motion''' is the apparent motion of a [[planet]] in a direction opposite to that of other bodies within its system, as observed from a particular vantage point. '''Direct motion''' or '''prograde motion''' is motion in the same direction as other bodies.

While the terms ''direct'' and ''prograde'' are equivalent in this context, the former is the traditional term in astronomy. The earliest recorded use of ''prograde'' was in the early 18th century, although the term is now less common.<ref>{{Cite web | title = Prograde, adj. | date = 2012 | work = OED Online version | publisher = [[Oxford University Press]]|url = https://www.oed.com/dictionary/prograde_adj?tab=factsheet#28123458 }}</ref>