An accidental discovery might change how we think about one of the most mysterious structures in our solar system. The Oort Cloud, a large expanse of icy bodies revolving around the sun at a distance ...

The exact shape of the Oort cloud and how it is affected by forces beyond our solar system have, so far, remained mysterious. Now, researchers have developed a new model that suggests the inner ...

This story appears in the July 2013 issue of National Geographic magazine. The dust speck had been plucked from the tail of a comet more than 200 million miles away. Now, under an electron microscope ...