Charon's Canyons

Data from New Horizons' multispectral visual imaging camera produced this composite image of Pluto (foreground) and its large moon Charon, with the colors enhanced but processed identically to reveal the differences and similarities between the two tidally locked bodies. The reddish terrain at the north pole of Charon matches terrain at Pluto’s equator, while the dwarf planet is much brighter than its moon. Scientists speculate the polar feature on Charon is made up of tholins produced by the effects of sunlight on Pluto’s atmosphere, which bleeds across open space and freezes to the supercold polar surface on Charon. While the relative sizes of Pluto and Charon are roughly correct, the true distance between them is much greater. 

Charon-flyover animation created using data from New Horizons’ Long-Range Reconnaissance Imager (Lorri) and multispectral visible imaging camera, dubbed Ralph, takes the viewer from the dark deposit at the moon’s north pole south to a huge canyon, deeper and longer than Earth’s Grand Canyon, that stretches along the equatorial region.

The video moves south to a huge canyon, deeper and longer than Earth’s Grand Canyon, that stretches along the equatorial region.

Continuing to the south over the strangely smooth southern hemisphere, the short animation reaches a feature that resembles a mountain with a moat around it, which the mission team has dubbed Kubrick Mons. Using imagery with resolution as fine as 400 meters per pixel, the animators created a “flight” than descends from 1,000 mi. to 40 mi. over the surface.

Enhanced-color view of Charon’s disk displays the massive canyon system just north of the equator on the Pluto-facing side, which ranges more than 1,000 mi. in length and in places it is twice as deep as the Grand Canyon. “It looks like the entire crust of Charon has been split open,” says John Spencer, deputy lead of the mission’s geology and geophysics investigation team. “In respect to its size relative to Charon, this feature is much like the vast Valles Marineris canyon system on Mars.”  The size of the feature, and the fact that the plain to its south is relatively smooth, suggests to some scientists that Charon cracked when an internal ocean of water froze, sending a slurry of “water-based lavas” onto the surface in a process known as cryovolcanism. The image boasts details as small as 1.8 mi. across, but even higher-resolution imagery—as well as compositional data—remains stored on the nuclear-powered probe awaiting transmission back to Earth.

High-resolution composite of Lorri and Ralph images, with details as small as 0.5 mi. across, highlights the rough northern hemisphere of Charon, broken by canyons and craters, in contrast to the smooth rolling plains—informally named Vulcan Planum—south of the equatorial canyon.  Before New Horizons reached Pluto and its moons, planetary scientists had expected Charon to be relatively boring, with craters pocking a fairly uniform surface. Mission Project Scientist Hal Weaver says, “I predict Charon’s story will become even more amazing” as the science team begins to analyze data that is still stored in the spacecraft’s digital recorders.