The World Wide Web is loaded with information tools, but for anyone interested in the natural environment, Google Earth has to rank among the best. A simple search makes it quick to find and download. After starting the program, try putting some place names or coordinates into the search box at left.
For example, “34.2N 84.0W” (34.2 degrees north latitude, 84 degrees west longitude) puts you right into Lake Lanier. Clicking on the image date near bottom left makes a timeline of images appear, which allows you to go back in time. Going through the sequence makes for interesting satellite snapshots showing the development of Gwinnett County.
The system is most impressive when it shows tall features. Type “Mt. Everest” into the box. After it sharpens up, click and hold the mouse. Move it back and forth for an incredible view from the top of the world’s highest mountain.
From the peak to the Khumbu glacier on the left, you’re looking down a vertical drop of 10,000 feet. The “ripples” seen on the surface of the glacier are crevasses, or deep cracks which form in the ice as it slowly creeps downhill. Meltwater drains into the crevasses and then moves through the ice, forming its own tunnels until it emerges at the front end, or “snout” of the glacier.
Rock of the limestone type can have an internal plumbing system, too. Type “Horse Cave KY” into the box, and you’ll be taken to a landscape in Kentucky that seems oddly pockmarked. Zoomed in, those rounded patches turn out to be sinkholes. Water has dissolved the rock, making it collapse into funnel-shaped depressions. Click the “photos” checkbox to find photo links in downtown Horse Cave, showing the gaping mouth of Hidden River Cave right next to the drugstore.
Typing “42.9n 122.1w” into the box gets you to a huge hole filled with water, this one caused by a volcanic eruption. Six thousand years ago, Mount Mazama exploded so violently that there’s nothing left but its rim, and a new lake named Crater Lake, Ore.
But you don’t have to “fly” far from home to see spectacular features. “33.805n 84.14w” puts you on top of Stone Mountain, which isn’t volcanic. Instead, it represents the top of a mass of very tough granite, once deeply buried but now prominently exposed as everything around it has washed away.
Rudi Kiefer, Ph.D., is a professor of physical science and director of sustainability at Brenau University. His column appears Sundays.