Explore astronomy, from the latest trip to the International Space Station to alien planets outside our solar system.
Video: Just how big is Earth in comparison to the Sun, stars and other planets?
Two researchers say while a flight to Mars and back is technically feasible now, it would be more cost-effective to launch a one-way trip.
Crash made water on the Moon detectable for scientists.
The galaxy is so ancient that it probably doesn't exist in its earlier form and has already merged into bigger neighbors.
Light from the new record-holder takes roughly 13.1 billion years to reach Earth.
Animal rights advocates are protesting the plans to subject squirrel monkeys to the experiment.
Discovery leads astronomers to rethink what is known about hot Jupiters.
Private companies compete to develop vehicles, robots for lunar landings.
Leak could delay planned November launch.
Project involving skydiver Felix Baumgartner on hold until lawsuit with promoter is resolved.
Microgravity damages human cells, particularly stem cells that repair other cells.
NASA sent two medical doctors, a psychologist and an engineer to aid the rescue effort.
Astronomers locate new planets by looking at the movement or brightness of stars.
Former NORAD officer says aliens are coming on Oct. 13 to warn us about the dangers of gases released into the atmosphere.
The signing officially scraps NASA's previous moon-oriented goal and paves the way for a manned mission to an asteroid by 2025.
Eco-entrepreneur on politics, energy and Earth's resources.
Russell blogs about the day's top science and eco-news.