After making its flyby early Saturday morning the Cassini spacecraft captured this full-sized view of Enceladus from a distance of about 83,000 miles. (Image has been level-adjusted to bring out surface details. Original raw image can be seen here.)
318 miles across at its widest point, Enceladus’ wrinkled surface is composed of water ice that has been cracked, stretched and folded into ridges due to tectonic activity that may be the result of a liquid water interior. The water is definitely there….it’s being sprayed out into space through fissures in the moon’s southern hemisphere (see previous post) but the extent – and heat source – of that liquid water still remains to be discovered.
Being covered in ice makes Enceladus is extremely bright; it reflects nearly 100% of the sunlight that hits it. This also keeps the moon very cold…the surface temperature on Enceladus is -330º F. Still, some process is keeping parts of the moon warm enough for liquid water to exist, and this is what scientists on the Cassini team are trying to learn more about.