Encountering Neptune in 1989, NASA’s Voyager mission completed humankind’s first close-up exploration of the four giant outer ...

The orbits of the planets around the sun have been the source for many a scientific debate. Their current orbital properties ...

Over a thousand objects are now known to orbit the Sun beyond Neptune, and once again we can't imagine torturing school children by adding even a dozen of the biggest ones to the list of planets.

It’s hard to find a star more like the Sun in its early years than Kepler-51, and harder to find a planetary system more ...