SPACE

Over time, scientists determined that the cracked terrain stretching across Enceladus’ active south pole is in constant motion, stretching in some places and buckling in others as the cracks pinch and pull from gravitational forces. It is possible Enceladus is heated by a tidal mechanism similar to Jupiter's moon Io. Scientists discovered evidence of Enceladus’ internal ocean from gravity measurements based on the Doppler effect and the magnitude of the moon’s very slight wobble as it orbits Saturn. The data was consistent with the existence of a large global ocean inside the moon. The measurements suggested a large sea about 6 miles (10 kilometers) deep beneath the southern polar region, under an ice shell about 19 to 25 miles (30 to 40 kilometers) thick. Cassini flew by Enceladus for the last time in October 2015, but explorers will be poring over the data it sent home for years to come, planning for the day we return to delve deeper into its secrets. “As we...