NASA's Hubble Celebrates Decade of Tracking Outer Planets

Encountering Neptune in 1989, NASA's Voyager mission completed humankind's first close-up exploration of the four giant outer planets of our solar system. Collectively, since their launch in 1977, the twin Voyager 1 and Voyager 2 spacecraft discovered that Jupiter, Saturn, Uranus, and Neptune were far more complex than scientists had imagined. There was a lot