Europa’s plate tectonics

http://www.newscientist.com/article/dn26166-europas-icy-plate-tectonics-may-support-life.html?utm_source=NSNS&utm_medium=SOC&utm_campaign=hoot&cmpid=SOC%7CNSNS%7C2013-GLOBAL-hoot#.VA7ygIaUfjA

Volcano Sonic Boom

This is very cool.  Watch this video of a small volcano eruption.  You can see the shock wave clear the dust and clouds before it eventually reaches the cameras microphone.