Nearly 50 years since the first man walked on the moon, our morals are still stranded on Earth.
When NASA first started planning the Kepler mission, no one knew if the universe held any planets outside our solar system. Thousands of exoplanets later, the search enters a new phase.
Aliens are highly likely to undergo natural selection, shows new research.
Planetary protection protocols try to make sure we don't seed places like Mars with life from our planet. An astrobiologist argues they're misguided – especially with human astronauts on the horizon.
You may even be able to find other planets around the star closest to our solar system.
The planet is more similar to Earth than any other – except when it comes to supporting life.