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A radar snapshot of Mexico’s Yucatan Peninsula, taken from space, shows the clearest view yet of the 65 million-year-old crater left behind by a dinosaur-killing cosmic impact. The image is part of a newly released high-resolution mapping database for North America. THE RADAR IMAGERY was collected three years ago by the crew of the space shuttle Endeavour as part of an effort to create the world’s most detailed topographical maps. The outline of the 112-mile-wide (180-kilometer-wide) crater doesn’t stand out all that prominently, even in the new view that was released Thursday. It looks almost like a water stain from a glass sitting on top of the photo. Nevertheless, the elevation readings reveal what can’t be seen with the naked eye. Scientists believe that 65 million years ago, an asteroid or comet measuring miles across slammed into Yucatan’s northwest coastline near the present-day village of Chicxulub, 200 miles (320 kilometers) west of the tourist mecca of Cancun. The blast set off a catastrophe that eventually pushed more than 70 percent of Earth’s species, including the dinosaurs, into extinction. GEOLOGICAL SIGNATURE The globe-girdling geologic signature of the blast was first noted in 1980, but it took years longer to identify Chicxulub crater as the likely epicenter. Over millions of years, the accumulation of limestone sediments had erased nearly every trace of the crater. In the 1990s, scientists at last found the faint outline of the crater rim in Mexican survey data and gravity readings. The telltale sign was actually a chain of sinkholes, or “cenotes”: Above the unstable rim of the buried crater, the overlying limestone eroded and fractured more easily, leaving behind a pattern of depressions that would look like a semicircular trough — if you could see it. The “trough” sinks a mere 10 to 15 feet (3 to 5 meters) in elevation over 3 miles (5 kilometers) in width. It’s very subtle, which is why you can’t see it if you’re out there on the surface,” said Michael Kobrick, the project scientist at NASA’s Jet Propulsion Laboratory for the Shuttle Radar Topography Mission. “But it stands right out on our data. I think this is the first remotely sensed image ... that shows the overall major structure of the Chicxulub crater.” PREVIOUS RESEARCH SUPPORTED University of Calgary geologist Alan Hildebrand, who was involved in the earlier gravity mapping of the crater, said the radar view supported what he and his colleagues saw in the 1990s. I’m delighted to see this image because it does so clearly show the valley associated with the cenote ring,” he told MSNBC.com. “It’s a beautiful mapping effort.” He said the image also serves to counter claims made by some researchers that the Chicxulub impact left several other topographical features in its wake. “I can’t see any trace of any of these other features in it,” Hildebrand said. “That’s telling me that they’re probably spurious.” Hildebrand said he planned to analyze the radar imagery in more detail and include it in his future presentations — which is a perfect illustration of what the Shuttle Radar Topography Mission was meant to do. COOPERATIVE PROJECT Click through a selection of Earth images captured from space by various satellites. The SRTM effort is a cooperative project involving NASA, the Department of Defense, the National Imagery and Mapping Agency and the German and Italian space agencies. Twelve trillion bytes of raw data, an information store equal to the entire contents of the Library of Congress, were collected during Endeavour’s round-the-clock, 11-day mission in February 2000. All those radar readings are being refined into 40 billion bytes of high-resolution 3-D imagery, covering 80 percent of the land mass between 60 degrees north and 56 degrees south. Kobrick said he expected researchers to use the Chicxulub imagery and other nuggets from the SRTM database in their own research. Thursday’s imagery release covered most of North America, stretching from Newfoundland to the Aleutian Islands, and from Guatemala to Canada’s upper reaches. But that’s just the start. Over the next year, we’re going to go continent by continent,” Kobrick said. “All of South America will be next, Eurasia, Australia, the Pacific Islands, and so on.”