In astronomy, the point in the orbit of a planet or comet at which it is farthest from the sun.
From greek apo- "away from" + helios "sun".
- Earth is farther from the sun at aphelion than at perihelion.
- Mercury's aphelion is nearly 43 million miles from the sun.
- The asteroid"s aphelion is farther away from the sun than Neptune"s orbit.
- Aphelion is the opposite of perihelion, which is the point in the orbit where a planet or comet is closest to the sun.
- Aphelion occurs in early July, when Earth is about 94.5 million miles from the sun.