periheeli

Perihelion is the point in the orbit of a planet, asteroid, or comet at which it is closest to the Sun. The opposite point, when the object is farthest from the Sun, is called aphelion. The distance at perihelion varies for each celestial body. For Earth, perihelion occurs around January 3rd each year, with the Earth being approximately 147.1 million kilometers from the Sun. Aphelion for Earth is around July 4th, when it is about 152.1 million kilometers away. While the Earth's orbit is nearly circular, this slight variation in distance does not directly cause the seasons. Instead, the tilt of the Earth's axis is the primary factor determining seasonal changes. The concept of perihelion and aphelion is a fundamental aspect of orbital mechanics, described by Kepler's laws of planetary motion. These laws explain that celestial bodies orbit the Sun in elliptical paths, with the Sun at one of the two foci of the ellipse. The speed of an object in orbit also changes, being fastest at perihelion and slowest at aphelion, another consequence of Kepler's second law. Understanding perihelion is crucial for calculating orbital trajectories and predicting the positions of celestial objects.