aphelion

American  

[uh-fee-lee-uhn, uh-feel-yuhn, ap-hee-lee-uhn] / əˈfi li ən, əˈfil yən, æpˈhi li ən /

noun

plural

aphelia

1. Astronomy. the point in the orbit of a planet or a comet at which it is farthest from the sun.

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aphelion British  

/ əˈfiː-, æpˈhiːlɪən /

noun

1. the point in its orbit when a planet or comet is at its greatest distance from the sun Compare perihelion

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aphelion Scientific  

/ ə-fē′lē-ən /

1. The point at which an orbiting body, such as a planet or comet, is farthest away from the Sun.

2. Compare apogee perihelion

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Other Word Forms

• aphelian adjective

Etymology

Origin of aphelion

1650–60; Hellenized form of New Latin aphēlium < Greek *aphḗlion ( diástēma ) off-sun (distance), neuter of *aphḗlios (adj.), equivalent to ap- ap- ² + hḗli ( os ) sun + -os adj. suffix. See apogee

Compare meaning

How does aphelion compare to similar and commonly confused words? Explore the most common comparisons:

• aphelion vs. perihelion

Example Sentences

The most surprising thing about this cycle, though, is probably when its extremes occur on the calendar: perihelion is in January every year, while aphelion is in July.

From Scientific American • Jun. 30, 2023

Earth reaches aphelion July 3, the most distant spot on its imperfect, annual orbit around the sun.

From Washington Post • Jul. 1, 2017

Satellites circling Mars have seen aphelion clouds sitting close to the surface at night, then rising 20 kilometers up in the afternoon.

From Science Magazine • Mar. 22, 2017

What is the period of revolution for a comet with aphelion at 5 AU and perihelion at the orbit of Earth?

From Textbooks • Oct. 13, 2016

When the earth leaves the aphelion, a reaction takes place, being most rapid in September.

From Outlines of a Mechanical Theory of Storms Containing the True Law of Lunar Influence by Bassnett, Thomas