Subsurface ocean may have been the cause of Charon's fractured surface
Thanks to the treasure trove of images and data collected by NASA's New Horizons spacecraft, mission scientists have formulated a theory on the geological process that created the vast chasms that mar the surface of Pluto's largest moon, Charon.
The above image was captured by New Horizons' Long-Range Reconnaissance Imager (LORRI) at a distance of around 48,900 miles (78,700 km) from Charon. It covers an area 240 miles (386 km) in length by 110 miles (175 km) in width, while boasting a resolution of 1,290 ft (394 m) per pixel. The lower half of the right hand image is color-coded to depict the elevation of the terrain.
Prior to the arrival of New Horizons, planetary scientists could never have anticipated that Pluto and Charon could play host to such a diverse range of geological features. From the vast network of ravines that mark the moon's surface, it is clear that Charon has experienced a period of tumultuous upheaval.
New Horizons mission scientists have put forward a theory as to how these scars came to form. Charon's surface is composed predominantly of a layer of water ice. Early in the moon's life, heat from the planet's interior, aided by the decay of radioactive elements, caused some of the ice to melt and trickle down deeper into the moon where it formed a subsurface ocean.
At some point in Charon's history, the underground ocean froze, increasing in volume and forcing the skin of the moon to crack open. This period of geological instability produced vast networks of fractures.
The largest concentration of the chasms, which is focussed around Charon's equatorial region, stretches an impressive 1,100 miles (1,800 km) and plunges to depths of 4.5 miles (7.5 km).