The sun is the most massive object in our solar system ... Ultimately, the question of why some planets have moons is still ...

Alignments of five or more planets are rare—there will be two more featuring five or more planets this year, but after that ...

However, it has no moons. Discovered in 1781, Uranus is the seventh planet in the solar system. Uranus spins in the opposite direction to Earth and most other planets; the spin is called ...

Researchers accounted for the previously overlooked structures of the dwarf planet and moon in computer simulations of a ...

Pluto likely acquired large moon Charon in a “kiss and capture” collision billions of years ago. It may have created a subsurface ocean on the icy dwarf planet.

Quasi-moons are "moons" that orbit planets and seem ... is simply an illusion. (The most famous quasi-moon of Earth is probably Kamo'oalewa, which could actually have true lunar origins.) ...

NASA’s Juno mission found Io’s biggest volcanic eruption ever. The explosion was stronger than all Earth’s power plants ...

People in the northern hemisphere will be able to see Saturn, Mercury, Neptune, Venus, Uranus, Jupiter and Mars during the planetary parade. The next full moon will happen on Feb. 12. Known as the ...

For more information on this year's full moons and biggest ... Venus is another planet that continues dominating the western sky after sunset. Venus and Saturn will have their closest approach ...