Worlds will align for a "planetary parade" in January, with four bright and easily visible to the naked eye. But an even ...

That said, Earth's moon is notably large in comparison to its parent. The only other one of the inner planets with a moon is Mars, which has two, but they are just tiny asteroid fragments.

Scientists think the larger moons of Pluto and Earth formed through a collisional process. Dwarf planet Pluto and our Earth are the only two worlds in our solar system with very large moons. These may ...

Planets orbit the Sun in roughly circular paths, and moons orbit around planets. Asteroids and comets move in paths which are more oval in shape. The Sun’s gravity holds all of these objects ...