New images from NASA's New Horizons mission to Pluto have put the dwarf planet's largest moon, Charon, center stage in all its high-definition color glory.

The images sent back from the New Horizons spacecraft suggest Charon has had a violent past and is much more interesting in terms of surface features than was expected, researchers say.

Instead of a somewhat monotonous crater-covered body similar to Earth's own moon, scientists are being treated to the sight of mountains, landslides, canyons and color variations across the face of Charon.

"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," says Ross Beyer, a New Horizons team member from NASA's Ames Research Center in Mountain View, California and the SETI Institute, "but I couldn't be more delighted with what we see."

At half the diameter of its dwarf-planet companion, Charon is the largest moon relative to its planet in the entire Solar System.

Some scientists have even suggested it's incorrect to call Charon a moon, arguing the moon and Pluto together should be considered a binary pair of dwarf planets.

The new images are among data captured on July 14 during New Horizons' flyby of Pluto, data the spacecraft has been sending back to Earth since Sept. 21.

Downlinking all the data gathered during the flyby will take months, NASA says.

Researchers say they are most intrigued by a huge system of canyons and fractures spanning Charon's equator, possible evidence of a massive geological upheaval at some point in the moon's past.

The 1,000-mile-long system is four times as long as Earth's Grand Canyon, and in some places, twice as deep.

"It looks like the entire crust of Charon has been split open," says John Spencer at the Southwest Research Institute in Boulder, Colorado. "With respect to its size relative to Charon, this feature is much like the vast Valles Marineris canyon system on Mars."

There are also unusually smooth areas on the moon's surface, suggesting recent active geological processes have smoothed over the impact craters that would be expected, the scientists say.

As New Horizons continues to send back data from 3.1 billion miles away from Earth, scientists are looking forward to even high-resolution images of Charon.