We actually know very little about what's going on inside Uranus and Neptune, causing researchers to propose that these ...

Neptune is the solar system's most distant planet, a cold, blue ice giant sitting nearly 30 times further from the sun than Earth. At that remote distance, temperatures plunge to nearly minus 200 ...

The Hubble Space Telescope has peered at Uranus, left, and Neptune to study the so-called "ice giant" planets, but little is known about their interior composition. - NASA / ESA / M. Showalter / L.

The eighth and most distant planet from the sun, Neptune, reaches opposition with the sun on Sept.23, when it will be in its best position for viewing for the year. Neptune is too faint to see with ...