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

PRAGUE, Czech Republic — The universe really is expanding — astronomers are proposing to rewrite the textbooks to say that our solar system has 12 planets rather than the nine memorized by generations ...

This image from a simulation of atmospheric flow shows temperature patterns on one of the newly discovered planets (61Virb), which is hot enough that it glows with its own thermal emission. A movie of ...

PRAGUE, Czech Republic — The universe really is expanding — astronomers are proposing to rewrite the textbooks to say that our solar system has 12 planets rather than the nine memorized by generations ...