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

When astronomers found a large world farther out than Pluto, it became one of the final nails in the coffin of our ninth ...

However, this year a powerful new telescope is coming online that could prove once and for all that there really is a ninth planet in our Solar System. The same year that Pluto was ignominiously ...

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

There are eight official planets (sorry, Pluto) in our solar system: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune. But astronomers have spent the better part of a century ...

"Or an impactor hits a planet, and they merge ... between each other but didn't lose a lot of material to the solar system. Pluto is bigger and started and ended up with much more rock than ...

Skywatchers: A six-planet alignment peaks this week as Mars, Jupiter, Uranus, Neptune, Venus, and Saturn come together for ...

Scientists have discovered a new type of planetary collision called “kiss-and-capture,” where Pluto and proto-Charon briefly ...

Charon is unusual because it is the largest moon in the solar system compared with its parent body. In fact, Charon and Pluto are so similar in size that they are considered a double dwarf planet ...

University of Arizona researchers have unveiled evidence of romance at the farthest reaches of the solar system: a cosmic ...

This provides another piece of the puzzle to understand how planets and ... Pluto-Charon Formation Scenario ... a clearer picture of how the outer solar system formed and evolved based on analyses ...

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