How are you celebrating Earth Day? If you're one of 10,000 Leap Motion devs with an early unit, you could very well be exploring Mount Everest or venturing through the Amazon, just by waving your hands. Google's Earth app, which has reportedly been downloaded more than a billion times, just scored a refresh today -- version 7.1 -- delivering Leap Motion gesture control to your desktop. Both the free and paid versions now support touch-free navigation through the USB desktop device, which is expected in stores next month. The update, however, available for Windows, Mac and Linux, is yours for the taking now.