An Earth-like planet with a pair of moons in orbit.

Artist's depiction of an Earth-like planet with it's orbiting moon.

An Earth-like planet facing an imminent collision with a comet.

Artist's depiction of a binary star system with a close orbiting planet.

Astronaut floating in deep space with an Earth-like planet in background.

An Earth-like planet rises over a rocky and barren alien world.

Artist's depiction of an Earth-like planet with a pair of moons in orbit.

Artist's depiction of an Earth-like planet with orbiting moon and a red planet.

A water covered world in deep space illuminated by a it's parent star.

A moon rises above a stormy gas giant planet.

Artist's depiction of a blue planet and it's orbiting small moons.

An artist's depiction of sunrise over a planet viewed from space.

A comet passing the Earth on its journey around the Sun.

A gas-giant exoplanet transiting across the face of its star.

A double star system as seen from a circling planet.

Light from a nearby star illuminates a massive ringed gas giant.

The hottest known planet in the Milky Way, called WASP-12b, is so close to its sunlike star that it is superheated to nearly 2, 800 degrees Fahrenheit.

A large sun heats this alien planet which bakes in its glow.

A comet passing the Earth on its return journey from around the Sun.

Flying life forms grace the crimson skies of the earth-like extrasolar planet Gliese 581 c.

An artisti's concept of an unusual, methane-free world partially eclipsed by its star.

Earth and the moon.

Earth and the moon.

Space Shuttle backdropped against Earth.

An Earth-like planet with its atmosphere illuminated by a nearby star.