Galileo Galilei, with a homemade telescope, noticed three points of light near Jupiter. Initially believing they were distant stars, Galileo’s repeated observations over several nights and realized ...

Collaborative work by amateur and professional astronomers has helped to resolve a long-standing misunderstanding about the composition of Jupiter's clouds. Instead of being formed of ammonia ice -- ...

With a rare black moon and the peak of the year's first major meteor shower already behind us, January is shaping up to be an ...

A rare four-planet conjunction will be visible most of this month as Venus, Jupiter, Saturn, and Mars light up the sky.

New research from a team of citizen scientists challenges the old idea that Jupiter's visible clouds are formed of ammonia ...

January's skywatching highlights include four planets visible to the naked eye, Venus and Saturn's conjoin, and red planet ...

A solar eclipse crossed North America. Two robotic landers reached the lunar surface, largely intact. The most powerful ...