Mathematicians calculated where the planet might be based on its effects on Uranus, and astronomers searched for less than an ...

In 1989, Voyager 2 became the first and only spacecraft to ever fly by Neptune, and images from that mission famously show a planet that’s a deep azure color. But in reality, Neptune is far more of a ...

In pictures of the farthest planets from the sun, Uranus looks like a pale-green orb, while Neptune usually looks much bluer. A new analysis revealed their true colors. Here's NPR's Nell ...