The number of satellites orbiting our planet is rising fast, thanks to private "megaconstellations" that pose various threats to space exploration and astronomy. But how big has the problem already become?

The Wolf Amendment, a law that prevents bilateral cooperation in space research between the U.S. and China, is preventing U.S. government-funded analysis of the Chang'e 5 moon samples.

This week is the best time in May to view the night sky. Here's everything you can see during May's dark skies, from an upside-down bear to some of the oldest stars in the universe.

Do the benefits of exercise differ by sex? The answer is yes, evidence suggests.