Neither one is “big.” Earth’s moon is 2,160 miles in diameter. Some scientists believe Pluto should be upheld, but others suggest that Pluto, UB313 and other icy denizens of the Kuiper Belt ...

NASA's New Horizons spacecraft took us to Pluto for the first time in July 2015. Scientists are astonished by the incredible features they've observed on the dwarf planet, including a 1,000 mile ...