Detailed Article on 'Aphelion'
Aphelion refers to the point in a celestial body’s orbit where it is farthest from the sun. This is a key concept in understanding orbital mechanics, particularly for planets, comets, and asteroids. For Earth, aphelion occurs around July 4 each year, when the Earth reaches its greatest distance from the sun at about 152 million kilometers (94.5 million miles).
The opposite of aphelion is perihelion, which refers to the point in the orbit when a celestial body is closest to the sun. The variations in distance between aphelion and perihelion are more noticeable for comets with elongated orbits, but for Earth, the difference is relatively small in terms of temperature or climate impact. However, aphelion is still a key event in understanding the dynamics of our solar system.
In terms of space missions, understanding aphelion is crucial for calculating trajectories and planning spacecraft travel, especially for missions to distant planets or asteroids. The orbit of the Voyager spacecraft, for example, takes it far beyond the aphelion of Earth, into the outer reaches of our solar system.