Sublime?

[rogerinnh]

The rings of Saturn are composed of dust and ice. What keeps the ice from submimating? After all these millions of years, why is there any ice left within the rings?

 

[odysseus145]

In a vacuum ice will sublime at about 200K. The temperature at Saturn according to spaceviews.com is 148K , so the ice should not sublime. <div class="Discussion_UserSignature"> </div>