The point in the orbit of a planet, comet, or artificial satellite in solar orbit at which it is farthest from the sun. The earth is at aphelion on about July 3. Compareperihelion.
Mathematics
Seeapse.
Astronomy
The point in an elliptical orbit around the Sun that is farthest from the Sun’s centre.
Space Exploration
The point at which an object, travelling in an elliptical orbit around the Sun, is at its farthest from the Sun. This is a solar-orbit apoapsis. The Earth is at its aphelion on 5 July.
Geology and Earth Sciences
Point in the Earth’s elliptical orbit at which the planet is farthest from the Sun. See alsoperihelion.
Geography
The point furthest from the sun of any body orbiting the sun; the Earth is at aphelion 152 000 000 km from the sun in July.