The number of planets that orbit the sun depends on what you mean by “planet,” and that’s not so easy to define ...

All seven of the other planets in our solar system are about to become visible at once in a great planetary alignment – ...

Using the Keck Planet Imager and Characterizer (KPIC), astronomers have performed high-resolution spectroscopic observations ...

One possibility is that a rogue planet, about 1–2 times Earth’s mass, influenced their paths early in the solar system's history. Another enigmatic group comprises high-inclination TNOs ...

Planetary science is the study of the celestial bodies that orbit stars, with a particular focus on our own solar system. This includes studying the formation and evolution of planets, the moons ...