Charon May Have Had Subsurface Water Ocean, LORRI Images Suggest

According to members of the New Horizons science team, the moon’s outer layer is primarily water ice.

New Horizons spacecraft is now on track for its next investigation, with NASA approval, of another Kuiper Belt Object starting in 2019. Even before the flyby, scientists speculated that Charon may have harbored liquid water, and that some water may still flow beneath its icy surface. But as the moon cooled over time, this ocean would have frozen and expanded.

Meet Serenity Chasma, a stunning rut on Pluto’s largest moon, Charon.

Charon is home to some incredible surface features, including canyon system stretching 1,000 miles across the face of the moon and measuring four times as long as the Grand Canyon and twice as deep in places, indicating a violent tectonic history. The lower portion of the image shows colour-coded topography of the same scene. When New Horizons took this image, a distance of 48,900 miles (78,700 km) separated the spacecraft and Charon.

The evidence comes from close analysis of images and elevation data collected last July when NASA’s New Horizons probe zoomed past Pluto and its moons. Charon’s Serenity Chasma is part of a series of fractures and faults visible on the surface of the planet; the entire system is approximately 1100 miles long and up to 4.5 miles deep. It’s possible that Charon could have been warm enough to cause water ice to melt seep down, creating a subsurface ocean.

The clues suggesting that Charon might have harbored a subsurface ocean were captured by New Horizons in one image taken with the Long Range Reconnaissance Imager (LORRI).

The photos of Charon show an area 240 miles long and 110 miles wide.

Pluto, and therefore Charon, are a long way from the sun, so the theory is the ocean would have been kept warm by radioactive decay and the internal heat of the formation of the moon. This landscape in particular shows that, somehow, the moon expanded in tis past, and Charon’s surface fractured as it stretched.