dione

Dione is a small moon of 349 miles (562 km) in mean radius orbiting Saturn every 2.7 days at a distance of 234,500 miles (377,400 km), which is roughly the same distance that the moon orbits around the Earth.

Dione's density is 1.48 times that of liquid water, suggesting that about a third of Dione is made up of a dense core (probably silicate rock) with the remainder of its material being ice. At Dione's average temperature of -304 degrees Fahrenheit (-186 degrees Celsius or 87 kelvins), ice is very hard and behaves like rock.

Very fine ice powder (equivalent to smoke) from Saturn's E-ring constantly bombards Dione. The dust in the E-ring ultimately comes from Enceladus, which has prominent geyser activity.