aphelion

[ uh-fee-lee-uhn, uh-feel-yuhn, ap-hee-lee-uhn ]

noun

, plural a·phe·li·a [uh, -, fee, -lee-, uh, uh, -, feel, -y, uh, ap-, hee, -lee-, uh].

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

aphelion

/ əˈfiː-; æpˈhiːlɪən /

noun

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

aphelion

/ 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

Derived Forms

• apˈhelian, adjective

Other Words From

• a·pheli·an adjective

Word History and Origins

Origin of aphelion¹

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

Word History and Origins

Origin of aphelion¹

C17: from New Latin aphēlium (with pseudo-Greek ending -ion ) from ap- + Greek hēlios sun

Example Sentences

The exact distances of Earth’s perihelion and aphelion change a bit from year to year because of the gravitational influence of the other planets, as well as that of the moon.

From Scientific American

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

But as of 2023’s aphelion, Earth’s center will be 152,093,250 kilometers from the center of the sun.

From Scientific American

At the far and slow-moving end of the orbit, approaching and departing from aphelion, there is just enough loss of solar radiation to disturb the already uneasy weather patterns, to chill down what is cold already, and turn the wet gray summer into white violent Winter.

From Literature

This eclipse will occur three weeks after the Earth has arrived at aphelion, the farthest point in the planet’s orbit from the sun, when the Earth’s umbral shadow appears largest in angular size.

From Scientific American