Despite its bathtub-ready appearance, Hyperion—Saturn's largest irregularly shaped moon—is anything but spongy.

Our universe may have been born from a previous universe's "big bounce." But we'll never know too much about that universe, a new theory suggests.

A NASA satellite studying this summer's first shiny polar clouds, which appear 50 miles (80 kilometers) above the Earth, may demystify the strange phenomena.

NASA's Mars rover Opportunity will descend into the planet's enormous Victoria Crater late next week, mission scientists announced yesterday.

The latest crisis on the International Space Station raises the question: How to evacuate in an emergency?

A space shuttle leaves a ghostly knot above Florida, soccer stars scrimmage on a glacier, and Spaniards leap seven babies in a single bound.

A large basin on Mars's northern plains really did once hold a giant ocean, suggests new research into the planet's shifting poles.

Evidence of an expanding universe will have disappeared from view in a hundred billion years, throwing any future versions of cosmic science back to 19th-century models, according to a new essay.

Mars's soft center likely won't solidify from the inside out, as Earth's core has, despite the fact the two planets share similar elements, European scientists say.

A thin layer of the sun's atmosphere called the chromosphere is heated up by sound waves carried from the star's interior by magnetic fields, new research suggests.

Astronomers found 28 new planets outside the solar system in the past year, and the increased rate of exoplanet discovery suggests the galaxy is brimming with other worlds.

An orangutan rampaged at a zoo already infamous for a croc attack, Mars came into sharp focus, rare white lions roared into the spotlight, and more.

An accidental skid by the Mars rover Spirit turned up what experts say is proof that the red planet was once quite wet.

A Neptune-size planet likely covered in hot—but solid—water has been discovered in a snug orbit around a nearby star, a team of astronomers announced today.

New theories about what's creating geysers of water on Saturn moon's Enceladus may put hopes for life there on ice.