How many dwarf planets are there in our solar system? The recent discovery of 2017 OF201 makes the tally anywhere between ...

Pluto was long considered our ninth planet, but the International Astronomical Union reclassified Pluto as a dwarf planet in ...

The planets in order from the Sun are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. If you include the ...

Scientists may have discovered a dwarf planet far beyond Neptune — an unearthing that may disprove a longstanding theory ...

A team of astronomers believe they may have discovered a new dwarf planet—just like Pluto—on the edge of our solar system. The object—which orbits out beyond Neptune—has been named "2017 OF201" by the ...

The dwarf planet also has one provisional moon, which is nicknamed MK 2. Discovery: March 31, 2005. Size: 888 miles in diameter (1/9 the size of Earth) Distance from sun: 4.3 billion miles.

The dwarf planet is known for cryovolcanism, a phenomenon where subsurface liquids, mainly briny water, seep to the surface. If organic compounds had formed in an underground ocean, they could ...

Though Pluto has formally been considered a dwarf planet for almost two decades, it still has many lessons left for planetary scientists — including hints about how the solar system formed.