Perihelion is the point at which an orbiting body is closest to the sun. The word comes from Greek and literally means around (peri) the sun (helios).

Perihelion, the point in a planet’s orbit where it is closest to the Sun, is a fascinating phenomenon that shapes much of our understanding of planetary motion. While Earth’s proximity to the Sun ...

Viewed from above, our solar system's planetary orbits around the sun resemble rings around a bulls-eye. Each planet, including Earth, keeps to a roughly circular path, always maintaining the same ...

Studying the orbits of thousands of exoplanets shows that large planets tend to have elliptical orbits, while smaller planets tend to have more circular orbits. This split coincides with several other ...

The planets of our solar system move in ellipses. We've known this, so we are told, ever since Johannes Kepler devised his laws of planetary motion in the early 1600s. While it's true that orbits are ...

Researchers based at Aarhus University measured the orbital eccentricity of 74 small extrasolar planets and found their orbits to be close to circular, similar to the planets in the solar system, but ...

How does a planet’s size influence its orbit around its parent star? This is what a recent study published in the Proceedings of the National Academy of Sciences hopes to address as a team of ...

The Solar System is remarkably regular, its eight planets orbiting the Sun in the same direction in very nearly circular trajectories. Their orbits lie nearly in the same plane, which is aligned with ...

Strange giant planets known as hot Jupiters, which orbit close to their suns, got kicked onto their peculiar paths by nearby planets and stars, a new study finds. After analyzing the orbits of dozens ...