NASA has revealed stunning new images of Pluto’s moon Charon, taken by New Horizons, showing vast and varied surface features that hint at a violent history. Originally expected to be a grey, monotonous world, Charon has been shown to be covered in mountains, canyons, craters, and more.
Charon measures 1,214 kilometers (754 miles) in diameter, making it half the size of Pluto. The images, taken during the flyby on 14 July, show a huge canyon system that stretches more than 1,600 kilometers (1,000 miles) across its surface, and possibly onto the far side – which New Horizons wasn’t able to observe, owing to its relatively brief flyby. The striking reddish north region, informally named Mordor Macula, is also seen, which may be remnants of Pluto’s atmosphere.
These enhanced colour images show how Charon differs from Pluto in its appearance. NASA/JHUAPL/SwRI.
The canyon is four times as long as the Grand Canyon and in some parts twice as deep. Interestingly, in tandem with other faults on the surface it suggests Charon went through some major geological changes in its past. "It looks like the entire crust of Charon has been split open," said John Spencer, deputy lead for the New Horizons Geology, Geophysics and Imaging (GGI) team in a statement. "With respect to its size relative to Charon, this feature is much like the vast Valles Marineris canyon system on Mars."
The craters in the southern region, meanwhile, appear to be smaller than their northern counterparts – suggesting the surface of Charon’s southern hemisphere is "younger," meaning the surface has been the subject of more recent geological changes, possibly cryovolcanism. "The team is discussing the possibility that an internal water ocean could have frozen long ago, and the resulting volume change could have led to Charon cracking open, allowing water-based lavas to reach the surface at that time," said Paul Schenk, a New Horizons team member from the Lunar and Planetary Institute in Houston.
The moon as a whole, though, is proving to be vastly more impressive than anyone had imagined. "We thought the probability of seeing such interesting features on this satellite of a world at the far edge of our Solar System was low," said GGI affiliate Ross Beyer in the statement, "but I couldn't be more delighted with what we see."
NASA is continuing to release new images from New Horizons every week, with even better images of Charon and of course Pluto still to come.
Image in text: The Long Range Reconnaissance Imager resolved details as small as 0.8 kilometers (0.5 miles) in this composite image. NASA/JHUAPL/SwRI.
Below: An animated flyby over Charon.