There are demos aplenty promoting Google's new GIS tool - Google Earth. But I needed to have an abbreviated demo visiting the Opportunity Rover on Mars. Using Google Earth helps the user track the rover missions extremely well, not only allowing one to place themselves in the Martian environment alongside the rovers, but to examine the history and review the media collections associated with each - in context. IMHO, this is something no web page could do as well (although there's plenty ...