Perihelion vs. Aphelion — What's the Difference?
By Tayyaba Rehman — Updated on October 30, 2023
Perihelion is when a planet is closest to the Sun in its orbit, while Aphelion is when it's farthest.
Difference Between Perihelion and Aphelion
Table of Contents
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Key Differences
Perihelion and Aphelion are terms that refer to the positions of a planet, specifically Earth, in its orbit around the Sun. These terms help in understanding the elliptical shape of a planet's orbit.
At Perihelion, Earth is at its closest distance to the Sun. This occurs around January 3rd every year. On the contrary, at Aphelion, Earth is at its farthest distance from the Sun, which usually happens around July 4th.
Even though Earth is closer to the Sun during Perihelion, it doesn't mean temperatures are necessarily warmer. The seasons we experience are primarily due to the tilt of Earth's axis. Conversely, during Aphelion, even though Earth is farther, the Northern Hemisphere experiences summer.
The terms Perihelion and Aphelion are not exclusive to Earth. They are used for any celestial body orbiting the Sun. For instance, Mars will also have its Perihelion and Aphelion points during its orbit.
The difference in Earth's distance from the Sun between Perihelion and Aphelion is about 5 million kilometers. The effects of these points in Earth's orbit are more subtle than one might think and are overwhelmed by other climatic factors.
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Comparison Chart
Position
Closest to the Sun
Farthest from the Sun
Occurrence
Around January 3rd
Around July 4th
Effect on Seasons
Not direct cause of warmth
Not direct cause of cold
Distance Variation
Shortest from Sun
Longest from Sun
Used for
Any celestial body's orbit
Any celestial body's orbit
Compare with Definitions
Perihelion
The position in an orbit where speed is the greatest.
At Perihelion, the Earth's orbital speed slightly increases.
Aphelion
The maximum distance between a celestial body and the Sun in its elliptical orbit.
Mars has a more pronounced difference between its Aphelion and Perihelion compared to Earth.
Perihelion
A term derived from Greek meaning "near the Sun."
The word Perihelion, when broken down, indicates proximity to the Sun.
Aphelion
The point in Earth's orbit farthest from the Sun.
During Aphelion, Earth is approximately 94.5 million miles from the Sun.
Perihelion
The minimum distance between a celestial body and the Sun in its elliptical orbit.
Mars' Perihelion brings it significantly closer to the Sun than when it's at Aphelion.
Aphelion
The position in an orbit where speed is the least.
At Aphelion, the Earth's orbital speed slightly decreases.
Perihelion
The opposite of Aphelion in an orbital cycle.
While Aphelion represents the farthest point, Perihelion signifies the nearest one.
Aphelion
A term derived from Greek meaning "far from the Sun."
Aphelion, in its Greek roots, denotes distance from the Sun.
Perihelion
The point in Earth's orbit closest to the Sun.
During Perihelion, Earth is approximately 91.4 million miles from the Sun.
Aphelion
The opposite of Perihelion in an orbital cycle.
Aphelion and Perihelion are crucial in understanding the elliptical shape of orbits.
Perihelion
The point in a solar orbit where the orbiting body is closest to the sun.
Aphelion
The point on the orbit of a celestial body that is farthest from the sun.
Perihelion
(astronomy) The point in the elliptical orbit of a comet, planet, etc., where it is nearest to the Sun.
Aphelion
The point in the elliptical orbit of a comet, planet, or other astronomical object, where it is farthest from the Sun.
Perihelion
(figurative) The highest point or state; the peak, zenith.
Aphelion
That point of a planet's or comet's orbit which is most distant from the sun, the opposite point being the perihelion.
Perihelion
That point of the orbit of a planet or comet which is nearest to the sun; - opposed to aphelion.
Aphelion
Apoapsis in solar orbit; the point in the orbit of a planet or comet that is at the greatest distance from the sun
Perihelion
Periapsis in solar orbit; the point in the orbit of a planet or comet where it is nearest to the sun
Common Curiosities
When is Earth at Aphelion?
Earth reaches Aphelion around July 4th.
What is Perihelion?
Perihelion is when a planet, like Earth, is closest to the Sun in its orbit.
Do Perihelion and Aphelion affect our seasons?
While they play a role, the tilt of Earth's axis has a more direct influence on seasons.
Does Earth move faster in its orbit during Perihelion or Aphelion?
Earth moves slightly faster during Perihelion.
What does Aphelion mean?
Aphelion is the point in a planet's orbit when it's farthest from the Sun.
Is Earth warmer during Perihelion since it's closer to the Sun?
Not necessarily, as the tilt of Earth's axis and atmospheric conditions play more dominant roles in temperature.
When does Perihelion occur for Earth?
Perihelion for Earth typically occurs around January 3rd.
Are Perihelion and Aphelion terms only for Earth?
No, these terms can be used for any celestial body orbiting the Sun.
Do all planets have Perihelion and Aphelion points?
Yes, all planets with elliptical orbits around the Sun have these points.
What's the difference in distance between Perihelion and Aphelion?
About 5 million kilometers for Earth.
Are these terms applicable to bodies orbiting stars other than the Sun?
Yes, but typically they'd be termed periapsis and apoapsis, or specific to the star's name.
Are the effects of Perihelion and Aphelion strong enough to cause noticeable climate changes?
On Earth, other factors like axial tilt play a more dominant role, making the effects of Perihelion and Aphelion more subtle.
What is the origin of the word Perihelion?
It's derived from Greek, meaning "near the Sun."
Where does the term Aphelion come from?
Aphelion also has Greek origins, meaning "far from the Sun."
How do Perihelion and Aphelion relate to a planet's orbital speed?
A planet moves faster at Perihelion and slower at Aphelion due to gravitational dynamics.
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Written by
Tayyaba RehmanTayyaba Rehman is a distinguished writer, currently serving as a primary contributor to askdifference.com. As a researcher in semantics and etymology, Tayyaba's passion for the complexity of languages and their distinctions has found a perfect home on the platform. Tayyaba delves into the intricacies of language, distinguishing between commonly confused words and phrases, thereby providing clarity for readers worldwide.
