Carolyn Porco just tweeted about a beautiful image from Cassini, showing the icy moon Tethys hanging in space:
How forbidding and lovely!
Tethys is big, about 1100 km (660 miles) across (about 1/3 the diameter as our own Moon). Its density is actually a bit less than that of water, so it’s most likely predominantly composed of water ice. The surface is bombarded with craters, including the big one at the bottom called Melanthius. Read More