Don't worry, we're not being invaded by aliens — not yet anyway; this "UFO" is nothing more than a rare cloud. Looking like something out of an alien invasion movie, the massive 'lenticular cloud' ...

These noctilucent clouds, reflecting light from the sun after sunset, have been visible in Martian skies for the past four fall seasons. Credit: NASA / JPL-Caltech / MSSS A rover got a new view of ...

Astronomers have recently detected potential signs of microbial life on the exoplanet K2-18b, an ocean-covered world located 120 light years from Earth. This discovery suggests that the planet could ...