Astronomer Avi Loeb suggests that a quasi-satellite may be the "relic of an interplanetary mission by humanity from the 1960s ...

I/ATLAS is the third interstellar object ever discovered in our solar system. Telescope observations suggest it is a roughly ...

Two teams are set to explore dramatically different theories about what happened to Amelia Earhart. Each believes it’s closing in on the answer.

An oddly-shaped object in the South Pacific has sparked the latest push to solve one of the greatest mysteries of all time.

A pair of space probes cruising the solar system may be able to pass through the tail of the mysterious Manhattan-sized comet ...