What does apoapsides mean?
Apoapsides is the plural of apoapsis, the point in an orbit where a body is farthest from the central body it revolves around. The term is used in astronomy and orbital mechanics for objects such as comets, planets, satellites, and spacecraft. An orbit may have one apoapsis, while apoapsides is used when referring to the farthest points in several orbits or to the corresponding points in a system with multiple orbiting bodies. In orbits around Earth, the related term apogee is often preferred; for an orbit around the Sun, aphelion is common. The general astronomical term apoapsis is especially useful when discussing different central bodies in the same context. The word belongs to formal scientific vocabulary but is understandable to general readers when its meaning is explained. It also has a precise counterpart: the periapsis is the point of closest approach.
nounThe plural of apoapsis: the point or points in an orbit at which a body is farthest from the body it orbits.
- The points in one or more orbits at which a body is farthest from the body it orbits.
"The study compared the apoapsides of several comets."
"The study compared the apoapsides of several comets."
"The images identify the apoapsides of both stars in the binary system."
The standard plural of apoapsis, used when referring to the points of greatest distance in more than one orbit or orbital system.
"The researchers plotted the apoapsides of the outer planets."
Every orbit has a point of maximum distance, and its name begins with apo-, meaning “away from.”
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Words that share this root
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How apoapsides is actually used
This is a specialized astronomical term. It is most common in formal astronomy writing and technical discussions of orbital mechanics, although it is also used in popular science.
Easily confused with apoapsides
A periapsis is the point closest to the central body, whereas an apoapsis is the point farthest from it.