Once dismissed as empty expanses between galaxies, cosmic voids are becoming one of the most promising tools for probing the universe’s biggest mysteries.

The Defense Department has released a new trove of declassified documents about government UFO sightings.

From lava tubes on Mars to ice pockets on Europa, subterranean environments may offer the best chance of finding life—and living safely—beyond our planet.

Donald Trump has ordered the release of files related to aliens, UAP, and UFOs. If previous disclosures are any indication, get ready for a letdown.

As next-generation telescopes map this outer frontier, astronomers are bracing for discoveries that could reveal hidden planets, strange structures, and clues to the solar system’s chaotic youth.

From surveys of the pre-Sputnik skies to analysis of interstellar visitors, scientists are rethinking how and where to look for physical traces of alien technology.

Polling shows that nearly half of Americans now believe aliens have visited this planet—and that the number who aren't sure has dropped by two-thirds. The reasons why, experts say, are complicated.

NASA has set a 2030 deadline to build a 100-kilowatt nuclear reactor on the moon. It’s an ambitious but potentially achievable goal that could transform space exploration, experts tell WIRED.