Even the little-understood Oort Cloud, at the outer edges of our solar system beyond view, has a partly spiral structure.

Researchers discovered a planet-forming disk that lasted 30 million years. This challenges previous estimates of 10 million years.

How does a planet’s size influence its orbit around its parent star? This is what a recent study published in the Proceedings of the National Academy | Space ...

Scientists have identified another possible commonality between Earth and Mars: a solid inner core. Scientists have ...

It's certainly not a small island: It's about three times the size of Texas. But on most maps, Greenland looks almost as big as the entire continent of Africa. In fact, it's 14 times smaller than ...