Pluto’s Moon Charon May Have Ruptured From Within

Massive chasms on the dwarf planet's largest moon explained
Pluto's moon Charon in New Horizons color-processed image

The largest moon of the dwarf planet Pluto looks absolutely breathtaking in new high-resolution images captured during the New Horizon spacecraft's flyby, and released by NASA in September 2015. This particular image was snapped by the Ralph/Multispectral Visual Imaging Camera (MVIC) on the spacecraft and includes details as small as 1.8-miles across, according to NASA. The colors have also been enhanced, combining red, blue, and infrared images, so that Charon's various geological features are easier to see. NASA/JHUAPL/SwRI

When the New Horizons spacecraft returned the first closeup pictures of Pluto’s moon Charon last year, scientists were surprised to see a huge chasm gouging across the moon’s middle. Now they have a good guess as to what caused it: Charon is bursting at the seams.

Or at least it used to be. When Charon was young, it had a radioactive core to keep it warm. Beneath its icy shell, that warm center may have melted a watery subsurface ocean. Later, when the moon’s radioactive fuel ran out and the center cooled, that ocean may have frozen and expanded, splitting Charon across the middle.

The New Horizons team arrived at this hypothesis after finding evidence that parts of the surface ice had melted and re-frozen.

Charon’s chasms are about 1,100 miles long, or about four times longer than the Grand Canyon, and 4.5 miles deep in some places.