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

Dwarf Planets Learn more about Pluto and other dwarf planets, which are defined as objects that orbit the Sun and are nearly round, but that have not been able to clear their orbit of debris. The ...

Life outside the Earth is one of the biggest "what if" in history, but NASA is trying to put a end to the discussion - or add ...