NASA's New Horizons spacecraft launched in January 2006 and made history by returning the first close-up images of Pluto and its moons the following decade.Īfter flying within 7,800 miles (12,550 kilometers) of Pluto's icy surface on July 14, 2015, New Horizons continued at a rapid nine miles per second on to the Kuiper Belt.Īs it departed Pluto, the spacecraft looked back at the dwarf planet and captured a series of images of its dark side, backlit by the distant Sun.Īlthough Pluto's hazy atmosphere stood out as a brilliant ring of light, the dark side itself was of course hidden.

Once considered the ninth planet, Pluto is the largest member of the Kuiper Belt and the best known of a new class of worlds called dwarf planets. Pluto – which is smaller than Earth’s Moon – is a complex world of frozen plains and ice mountains as big as the Rockies. 'At the time, the illumination of Charon on Pluto was similar to that from our own Moon on Earth when in its first-quarter phase.'

'In a startling coincidence, the amount of light from Charon on Pluto is close to that of the Moon on Earth, at the same phase for each,' said Tod Lauer, an astronomer at the National Science Foundation's National Optical Infrared Astronomy Research Observatory in Tucson, Arizona.

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