The solar system has many more moons than the one we can see in the sky. But how many do we actually know about? And how many ...

A Harvard physicist who sounded the alarm earlier this month about a rare interstellar object passing through our solar system — and suggested it might be more than a comet — now says it could even be ...

Avi Loeb said bases this hypothesis on a July 21 image captured by the Hubble Space Telescope and shared by NASA.

Wow”, scribbled Jerry Ehman, encircling the mysterious 72-second burst from the stars, a signal so sharp and unearthly that ...