Astronomers have discovered an exoplanet that might have favorable conditions for liquid water. This planet, HD 20794 d, ...

It is located in a star system less than 20 light-years away, making it one of the closest candidates for further research.

Earth's unusual orbit through hot and cold conditions tests the limits of tolerability for any known lifeforms.

NASA's two stuck astronauts take their first spacewalk together since arriving at the space station last year.