Science

Follow PBS NewsHour’s complete coverage of Science and Technology stories.

WikiLeaks founder Julian Assange in London on Oct. 23.; Getty photo Update, 3:30 p.m.: Wikileaks says it has been ousted from its Amazon cloud hosting. .bbpBox10058229002272768 {background:url(http://a3.twimg.com/profile_background_images/3147857/WL_Hour_Glass.jpg) #9AE4E8;padding:20px;} p.bbpTweet{background:#fff;padding:10px 12px 10px 12px;margin:0;min-height:48px;color:#000;font-size:18px !important;line-height:22px;-moz-border-radius:5px;-webkit-border-radius:5px} p.bbpTweet span.metadata{display:block;width:100%;clear:both;margin-top:8px;padding-top:12px;height:40px;border-top:1px solid #fff;border-top:1px solid…

It's time for our weekly Just Ask feature, where the experts tackle your questions on science and technology. John Eichelberger, a volcano expert with the U.S. Geological Survey, answers the question, "Why Does the Earth Have Volcanoes, and…