Holiday calendar: Volcano in 3-D A stereo picture from the Multi-angle Imaging Spectroradiometer aboard NASA's Terra shows an ash plume rising from Sicily's Mount Etna Volcano on Oct. 29, 2002. A plume of volcanic ash pops off the page in this decade-old 3-D picture documenting the eruption of Sicily's Mount Etna. The image, captured by an instrument on NASA's Terra satellite on Oct. 29, 2002, illustrates how adding the third dimension comes in handy for scientific observations as well as multimillion-dollar movies. You need standard red-blue glasses to experience the stereo effect, but once you put on your specs, you're in for a treat: The 3-D view makes it easier to judge the relative heights of the ash plume and the surrounding clouds. If you don't have special glasses, you can still get a sense of the volcano's power by checking out the 2-D, natural-color view from Terra's Multi-angle Imaging Spectroradiometer. There's even a 3-second QuickTime animation that puts together a series of snaps from the satellite flyover. Satellites play a key role in tracking potentially dangerous natural phenomena around the world, including volcanoes. You can bet that Earth-observing satellites are keeping watch on three volcanoes that have recently started acting up: Mount Tungurahua in Ecuador, Mount Lokon in Indonesia and Mount Tolbachik in Russia. For the latest on all three, check out volcanologist Erik Klemetti's update on the Eruptions blog. This classic Etna picture was the focus of today's "Where in the Cosmos" contest on the Cosmic Log Facebook page. It took a few minutes for Hong Yaw Lim, Ryan Posey and Krystyn Allison-In Oneness to identify the mystery volcano, but to reward their efforts, I'm sending them pairs of cardboard 3-D glasses, provided courtesy of Microsoft Research's WorldWide Telescope project. Press the "like" button for the Facebook page and get ready for the next 3-D glasses giveaway after the first of the year. This is also today's offering from the Cosmic Log Space Advent Calendar, which features a different view of Earth from space every day from now until Christmas. For more visual treats, check out the links below: