The high-resolution mapping telescope on NASA's Mars Reconnaissance Orbiter has monitored the changing Martian landscape for more nearly eight years, but a fresh impact crater seen in an image released Wednesday is one of the most dramatic scientists have ever discovered.

The fresh crater, seen here in an image taken Nov. 19, 2013, spans 30 meters in diameter. The crater and ejecta rays appear blue in this enhanced image. See a larger version and a wider view. Photo credit: NASA/JPL/University of Arizona
 
The crater spans about 30 meters, or 100 feet, across and formed some time between July 2010 and May 2012. Researchers looking at pictures from the orbiter's context camera, a wide-angle imager used to complement MRO's main mapping instrument, noticed a new surface feature appearing in 2012 not there two years before.

Scientists requested MRO's High-Resolution Imaging Science Experiment, or HiRISE, to take a closer look. The camera captures the sharpest views of Mars ever taken from orbit, and it turned its aperture toward the crater site to image the region Nov. 19, 2013.

What they saw was a dazzling crater with ejecta rays extending outward in all directions up to 15 kilometers, or 9.3 miles, from the impact site. Whatever carved the bowl-shaped pit in the Martian bedrock caused one of the biggest explosive events ever seen on Mars since spacecraft began visiting the red planet.

Alfred McEwen, HiRISE's chief scientist at the University of Arizona in Tucson, said the estimated 30-meter diameter of the new crater puts it among the largest recent impacts seen by the eagle-eyed camera.

The biggest new crater previously found by HiRISE was 33.8 meters across, or about 111 feet in diameter.

"But this one is more spectacular looking with prominent dark rays," says McEwen, a professor of planetary sciences. "Most new craters found are smaller than 10 meters (33 feet)."

From the orbiter's altitude, the HiRISE camera has a pixel size of about one-quarter meter, or 10 inches.

Scientists say incoming rocks and small asteroids generate about 200 fresh craters per year, but few are as eye-catching as the one seen in November.

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