The mysterious Oort cloud is the source of many of our solar system's comets, but astronomers still have no idea what it ...

To see the parade, find a dark place with a clear view of the western horizon at nightfall. Mercury and Saturn will be low in the sky, brushing past each other in the fading glow of the evening sun, ...

A shell of icy objects at the edge of the solar system known as the Oort cloud has a pair of spiral arms that resemble a miniature galaxy, new research suggests.

But in the grand scheme of the solar system, Earth's Moon isn't as big as you might think. Oberon is Uranus’s second-largest ...

Researchers claim that there could be at least 1 million interstellar objects hiding in the Oort Cloud at the edge of our ...

A rare full seven-planet alignment will be visible in the early night sky between Feb. 22 and 28. We have the tips you need to best see all the planets.

The $488 million observatory is set to launch at the end of this month on a two-year mission to map the entire celestial sky.