How many dwarf planets are there in our solar system? The recent discovery of 2017 OF201 makes the tally anywhere between five and 18, plus hundreds of potentially undiscovered ones, depending on ...

In 2006, Ceres – located in our solar system’s main asteroid belt – was officially classified as a Dwarf Planet. This title refers to a body which is smaller than a planet, with many of the ...

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.

A possible new dwarf planet has been discovered at the edge of our solar system, so far-flung that it takes around 25,000 years to complete one orbit around the sun ...

Astronomers pointed out that the seven planets orbit TRAPPIST-1, a dwarf star that is much younger than our sun and should burn for an additional 10 trillion years — more than 700 times longer ...

A model of the planet Saturn stands near Route 1 in Westfield, Maine, Friday, May 9, 2003. (Robert F. Bukaty/AP File) For the first time since 2008, two new planets are being added to one of ...