You're not seeing double; these are two images of the same world: icy, cratered Rhea, the second-largest natural satellite of Saturn. Made from images captured by the Cassini spacecraft's narrow-angle camera on Feb. 9 (with a few fillers from the wide-angle cam) these are high-def, hyper-color composite views of a battered moon that to our eyes would otherwise look mostly gray and white.
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The left image shows Rhea (that's pronounced REE-ah) from a distance of about 51,200 to 46,600 miles (82,100–74,600 km) and the right is a bit closer, made of images captured from about 36,000 to 32,100 miles (57,900–51,700 km). The entire image was assembled by Heike Rosenberg and Tilmann Denk at Freie Universität in Berlin, Germany.
The images were acquired during T-109, a targeted flyby of Titan.
Rhea is Saturn's second-largest moon after Titan, but at 950 miles (1,530 km) across Rhea is less than a third of its larger sibling's diameter. Its high reflectivity is a result of being mainly composed of water ice, which is harder than rock at Rhea's frigid surface temperatures of -300 degrees Fahrenheit (-185 degrees Celsius).
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Rhea is also extensively fractured and cratered. In fact it's one of the most - if not the most - heavily-cratered worlds in the entire solar system, a hallmark of an extremely ancient surface.