Meaning & use
aphelion
Last updated
Meaning
nouncountabletechnical
The point in the orbit of a planet or comet where it is farthest from the sun.
Grammar: Countable; often used with 'at' or 'reach': at aphelion, reach aphelion.
Patterns
- at aphelion
- reach aphelion
- the aphelion of something
Earth is at aphelion in early July, when it is about 152 million kilometers from the sun.
The comet will reach aphelion next year and then begin its long journey back toward the sun.
Word forms
| plural | aphelia |
|---|
Common combinations
- at aphelion
- At aphelion, the planet moves more slowly in its orbit.
- reach aphelion
- The comet will reach aphelion beyond the orbit of Neptune.
- the aphelion of a comet
- Astronomers calculated the aphelion of the comet to be very far out.
Synonyms and how they differ
Opposites
Word family
- perihelion noun
- The opposite point, where the orbit is closest to the sun.
Commonly confused: aphelion or perihelion?
aphelion vs perihelion
Perihelion is the closest point to the sun; aphelion is the farthest.
Practice
Which sentence uses 'aphelion' correctly?
Choose one answer.
Aphelion is the farthest point from the sun, so option 1 is correct. Option 0 reverses the meaning (that is perihelion). Option 2 uses 'aphelion' for the moon and Earth, which is wrong; aphelion is about distance from the sun. Option 3 is wrong because passing near the sun is perihelion, not aphelion.
Make it your own
Write a sentence using “aphelion”, then check it and compare it with the examples above.