With sapphire waterfalls, lava rain and orbits around dead stars, these distant worlds push the limits of what’s possible.

When you buy through links on our articles, Future and its syndication partners may earn a commission. An illustration of confirmed dwarf planets and their moons. From left to right: Pluto (with ...

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 whom ...