A new image of the largest of Pluto’s five known moons shows various craters and chasms (canyons).



“The most pronounced chasm, which lies in the southern hemisphere, is longer and miles deeper than Earth’s Grand Canyon,” said New Horizon team member Dr William McKinnon of the Washington University in St. Louis. “This is the first clear evidence of faulting and surface disruption on Charon.”

“New Horizons has transformed our view of this distant moon from a nearly featureless ball of ice to a world displaying all kinds of geologic activity,” he said.

The most prominent crater, which lies near the south pole of the moon, is about 60 miles (96.5 km) across. The brightness of the rays of material blasted out of the crater suggest it formed relatively recently in geologic terms, during a collision with a small Kuiper Belt Object (KBO) some time in the last billion years.

“The darkness of the crater’s floor is especially intriguing,” Dr McKinnon said.

One explanation is that the crater has exposed a different type of icy material than the more reflective ices that lie on the surface.

Another possibility is that the ice in the crater floor is the same material as its surroundings but has a larger ice grain size, which reflects less sunlight. In this scenario, the impactor that gouged the crater melted the ice in the crater floor, which then refroze into larger grains.

An intriguing dark region near Charon’s north pole stretches for 200 miles (322 km). More detailed images that New Horizons will take around the time of closest approach to the moon on July 14 may provide hints about the origin of this region.