There are plenty of short-period comets buzzing around the inner Solar System, but they shed some of their outer layer of ice on every visit. Even those that started off quite large have shrunk ...

How do you find a comet that could pose a threat to Earth but hasn't passed our planet in the last 200 years or more? You look for its footprint.

A widely held view is that these vital components were deposited on Earth by a long bombardment of icy comets. Comets are made of dust and ice. Astronomers have examined the water contained in ...

which likely happened because the boulder's movement exposed icy layers beneath it. As remnants of the primordial solar system, comets tell a lot about the early stage of solar system, making them ...