NASA's scaled-back spacecraft-sterilization process may be helping contaminate Martian life before we even discover it, scientists say.

Like a bullet hitting a bullet, is how NASA described its attempt to cause a collision between a probe and a massive comet.

On July 20, 1969, half a billion people watched this footage of Neil Armstrong as he became the first person to set foot on the moon.

Astronauts aboard the International Space Station caught a view of Hurricane Emily far above the furor of the record-setting storm.

Camera phone images from commuters caught in last week's London bombings defined coverage of the atrocity. Police hope the pictures can also help bring the bombers to justice.

Two years after the Columbia disaster, Discovery will launch tomorrow, carrying with it the hopes of the waning U.S. shuttle program.

The theory of physics states that for every particle of matter created by the big bang that started the universe, there should be a particle of antimatter. The trouble is, where is the antimatter?

Like a bullet hitting another bullet, NASA's Deep Impact probe successfully crashed into Comet Tempel 1 yesterday, causing a spectacular explosion worthy of the Fourth of July.

NASA's Deep Impact spacecraft will be launching a projectile into the surface of comet Tempel 1 on Monday, possibly causing the most spectacular fireworks on America's Independence Day.

What is the biological basis of consciousness? How long can humans live? A top research journal lists the 25 most important questions facing science today.

This cat's-eye-shaped cloud around the small star Fomalhaut appears in the clearest image yet of one of our closest celestial neighbors.

Planning spectacular fireworks this Fourth of July, space scientists intend to slam a probe into comet Tempel 1, causing an explosion that may be visible on Earth.

Cosmos 1, the world's first solar sail spacecraft, was lost after its booster rocket failed to reach space, the Russian space agency said.

Scientists have identified the most Earthlike planet ever found outside our solar system.

Everyone knows the Star Wars galaxy is located "far, far away." But how realistic are the alien worlds described in the science fiction saga?