Aphelion is the point in an orbit where a celestial body, such as a planet or comet, is farthest from the Sun. For Earth, this occurs around early July each year, when it is about 94.5 million miles away from the Sun. The term "aphelion" comes from the Greek words "apo," meaning away, and "helios," meaning sun. It is part of the broader concept of orbital mechanics, which also includes the term "perihelion," the point where a celestial body is closest to the Sun. Understanding aphelion helps scientists study the effects of distance on climate and seasons.