noun
- plural of aphelion; the points in the orbits of planets or other objects where they are farthest from the sun
Usage: astronomy; technical
Examples
- Earth reaches its aphelion in early July each year.
- The aphelions of the outer planets occur at different times in their orbital cycles.
- Astronomers track the aphelions of comets to predict their future positions.
- At aphelion, planets move more slowly in their orbits than at perihelion.
- The distance between aphelions and perihelia varies greatly among different planets.