Days Before Flyby, Ultima Thule Still Mysterious
NASA's New Horizons spacecraft is about to visit the most distant object ever explored by humans.
NASA's New Horizons spacecraft is about to visit the most distant object ever explored by humans. Though NASA scientists know the approximate size of Ultima Thule, on Dec. 31, 2018, the object’s shape, color, and albedo (how much light it reflects)—and whether the flyby will be a success—is still a mystery.
