One of the most prominent features on Pluto is the informally named Cthulhu Regio, also called “the whale,” which stretches across 1,900 miles (3,000 km). Cthulhu Regio is pockmarked with craters, which suggests it is billions of years old — much older than the craterless, young “heart” it borders. Scientists have said the dark region’s reddish coloring might come from complex hydrocarbons.
How Did Pluto Get Its ‘Whale’?
