The solar system's two most distant worlds may be ready to give up their secrets
In the cold periphery of the solar system, two enigmatic sentinels saunter around the sun. One circuit along their vast orbits takes on the order of a century. Seasons are measured in decades. At such great distances from Earth, these worlds give up their secrets slowly. While every other planet in our solar system has been repeatedly poked and prodded by orbiters and landers, Neptune and Uranus, save a brief tour in the 1980s, remain largely unexplored.
Thirty years ago, the Voyager 2 spacecraft tore past Uranus, then flew by Neptune less than four years later. These quick sojourns introduced scientists to two planets that had been vague blue splotches in their telescopes. In the years since, bigger and better instruments have teased out a bit more information and revealed a few surprises.