Although Pluto's reddish colouring has been known for decades, this is the first time it has been directly observed.
In the 85 years that we've known about Pluto, it's never been more than a blurry dot—even through our most powerful Earth-orbiting telescopes. But thanks to NASA's New Horizons spacecraft, currently approaching Pluto for its long-awaited flyby on on July 14th, we now have a better idea than ever of what the dwarf-planet really looks like.
Most popular renderings of Pluto are a cooler bluish grey. This is perhaps a result of our conception of the body as comprised mostly of ice, which we know to be blue or white on Earth. But last week, NASA has released new renderings that confirm we've been picturing it wrong all along. Pluto is red.
According to NASA, "the reddish color is likely caused by hydrocarbon molecules that are formed when cosmic rays and solar ultraviolet light interact with methane in Pluto's atmosphere and on its surface." And although Pluto's reddish colouring has been known for decades, this is the first time it has been directly observed.
These new, detailed renderings are a composite of images taken with the Long Range Reconnaissance Imager ("LORRI"), designed to capture high resolution images from visible wavelengths, and Ralph, a telescope that can capture images in the visual light near-infrared imaging spectrums. Topographical information from LORRI was coloured with images from Ralph.