aphelion
noun
ˌap-ˈhēl-
Did you know?
Aphelion and perihelion are troublesome terms. Which one means a planet is nearest to the sun and which means it is farthest away? An etymology lesson may help you keep those words straight. Just remember that the "ap" of aphelion derives from a Latin prefix that means "away from" (the mnemonic "'A' for 'away'" can help too); peri-, on the other hand, means "near." And how are aphelion and perihelion related to the similar-looking astronomical pair apogee and perigee? Etymology explains again. The "helion" of aphelion and perihelion is based on the Greek word hēlios, meaning "sun," while the "gee" of apogee and perigee is based on gaia, meaning "earth." The first pair describes distance in relation to the sun, the second in relation to the Earth.
Examples of aphelion in a Sentence
Jamie Carter, Forbes, 4 Jan. 2025
Such a circumstance will happen in 2027: On March 4 of that year, Mars will be at aphelion, its farthest point from the sun.
—Joe Rao, Space.com, 10 Jan. 2025
July 3: Earth will be at aphelion, the farthest point in its orbit from the sun.
—Phil Plait, Scientific American, 9 Jan. 2025
Earth’s Elliptical Orbit Earth’s elliptical orbit causes slight variations in solar energy, with about 7% more sunlight reaching Earth during perihelion than aphelion.
—Jamie Carter, Forbes, 4 Jan. 2025
See All Example Sentences for aphelion
Cite this Entry
“Aphelion.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/aphelion. Accessed 20 May. 2025.
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aphelion
noun
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