NASA's Voyager mission launched in the 1970s. Today, it's making history as it conducts new science. But how are two ...

Despite the lack of a dedicated mission to the planet, scientists have learned plenty through ground observations and space telescopes ...

After a decade-long search, some scientists say a growing number of clues point to the existence of a hidden planet in the Kuiper Belt beyond Neptune — and they may soon have the opportunity to find ...