Imagine a planet twice as wide as Earth, covered in an ocean that smells like sweet cabbage. Every day, a faint red star warms this ocean world and the uncountable masses of hungry, plankton-like ...

The hunt for intelligent life beyond Earth has quietly entered a more exacting phase, and one small, cool star has become a proving ground for how serious that search can be. TRAPPIST-1, a dim red ...

The most prolific planet-hunting machine in history has signed off. NASA's Kepler space telescope, which has discovered 70 percent of the 3,800 confirmed alien worlds to date, has run out of fuel, ...