ScienceJuly 31, 2026

aphelion

uh-FEE-lee-uhn

Definition

The point in the orbit of a planet, asteroid, or comet where it is at its greatest distance from the Sun.

Etymology

Derived from the Greek words 'apo' (away) and 'helios' (sun), the term was coined in the 17th century to describe the point in an orbit furthest from the Sun.

In the news

In this article, aphelion is used to identify the specific part of Mercury's orbit where it is farthest from the Sun, a location where researchers discovered radiation belts frequently form. This is significant because it highlights how planetary distance influences magnetic field behavior.

Mercury's Weak Magnetic Field Periodically Traps Solar Wind

Read the full article ↗

Universe Today

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