Researchers have confirmed the mass of a free-floating planet thanks to a lucky convergence of ground- and space-based ...

Mars has never looked more like a planet built for hiding secrets. A cluster of eight vast, water-carved caves appears almost engineered to shield fragile chemistry, or even biology, from the brutal ...

It's almost certainly not an extraterrestrial telegram. But waves that seemed to come from the vicinity of Proxima Centauri ...

"It's really not a question of robotic exploration or human exploration," Ehlmann said. "It is an 'and' — it's robotic and ...