aphelion •
\a-FEEL-yun\ • noun : the point in the path of a celestial body (such as a planet) that is farthest from the sun
Examples: The comet is
predicted to reach aphelion a mere 22 years from now.
"Although this
seems somewhat counter-intuitive for those of us in the northern hemisphere,
Earth is actually at perihelion in early January each year, and at aphelion? in
early July." — Alan Hale, Alamo Gordo News, August
14, 2014
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.
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