Orbits of planets

An orbit is the path a planet follows around the Sun. It has an elliptical shape with the Sun at one of the foci.

The speed of a planet depends on its distance from the Sun. The closer a planet is to the Sun, the faster it moves according to Kepler's second law.

Aphelion - the farthest point in a planet's orbit from the Sun, perihelion - the closest point. These points define the shape of an elliptical orbit.

Indeed, all planets in the Solar System move in one direction (counterclockwise) around the Sun, which is related to the process of Solar System formation.

A sidereal period is the time for one complete revolution of a planet around the Sun. A synodic period is the time between two identical configurations of a planet relative to Earth.

Orbital eccentricity is caused by gravitational interactions between planets and the Sun. Perfectly circular orbits would be possible only in an isolated system of two bodies.

The gravitational pull of the Sun keeps planets on their orbits, while gravitational interactions between planets cause disturbances in their motion, leading to changes in their orbits over time.

Orbital resonance is a phenomenon where the orbital periods of two planets are related by a simple numerical ratio. For example, a 2:1 resonance means that one planet completes 2 revolutions in the time it takes the other to complete 1.

Orbits of planets gradually change due to gravitational interactions with other planets, asteroids, and comets. These changes occur very slowly over millions of years.

Astronomers use telescopes to observe the positions of planets in the sky and then apply mathematical methods to calculate orbital parameters based on these observations.