'Census' of martian impact craters taken Mars has truly taken a cosmic beating, say U.S. researchers who've counted and cataloged 635,000 impact craters a kilometer or more in diameter on the planet. BOULDER, Colo., June 11 (UPI) -- Mars has truly taken a cosmic beating, say U.S. researchers who've counted and cataloged 635,000 impact craters a kilometer or more in diameter on the planet. A research team from the University of Colorado's Boulder campus said its database of impacts .62 miles across or larger on Mars would help in dating the ages of particular regions of the planet. "This database is a giant tool that will be helpful in scores of future Mars studies ranging from age-dating and erosion to planetary habitability and to other applications we have not even thought of yet," research leader Stuart Robbins said. In a sense it's like building a new and better hammer, which quickly becomes used by everyone. Creating the database was a long and sometimes tedious process, he said. "We have all this new information coming from Mars orbiters and landers that have helped generate far better maps illustrating the planet's topography and surface details," he said. I basically analyzed maps and drew crater rim circles for four years. Smaller diameter craters on Mars are the most numerous and are younger than the largest craters, he said. "The basic idea of age dating is that if a portion of the planet's surface has more craters, it has been around longer," Robbins said. However, he said, much of the planet has been "resurfaced" by volcanic and erosional activity, essentially erasing older geological features, including craters.