The universe is vast and teeming with stars – but if intelligent life exists, it may not be able to visit Earth.

Barack Obama's insisting the USA doesn't have little green men or alien spaceships locked up in an underground bunker somewhere ... but, if they ever visit Earth, he's volunteering to lead the ...

An alien invasion might sound like science fiction, but a scientist has now revealed what the terrifying consequences of an encounter might be. Professor Avi Loeb, head of Harvard University's Galileo ...

A Pentagon release of new UFO footage has revived the question of whether aliens could realistically travel to Earth.

In a world easily startled by sensationalism, Tyson offers a cool, gentle voice of reason amid the unchecked fascination with alien visitation.