Answer:
Kepler discovered that a planet does not orbit the Sun at a constant speed. Rather, at the point closest to the Sun known as the perihelion, the planet’s speed is faster.
Explanation:
The perihelion is the point that is closest to the sun in the orbit of a planet or other object that is in orbit around the sun. Objects with an elliptical orbit have not only a perihelion but also an aphelium, the point where the orbit reaches the greatest distance from the sun.
Objects with a parabolic or hyperbolic trajectory have a perihelion, but no aphelium. These jobs are therefore not periodic; the object passes through the sun only once, and the perihelion is the point of closest approach to the sun.
The Earth has an elliptical orbit and therefore has a perihelium and an aphelium. For the Earth, the perihelion usually falls between 2 and 5 January. As a result, the winters in the northern hemisphere are relatively slightly warmer and the summers slightly cooler than in the southern hemisphere.
