6/17/19
A small space rock crashed into the Red Planet's surface recently, producing a fresh crater that researchers estimate is 49 feet to 53 feet (15 to 16 meters) wide. The dramatic feature is clearly visible in a newly released image from NASA's Mars Reconnaissance Orbiter (MRO). The spacecraft has been imaging the Red Planet up close for more than 13 years using its High Resolution Imaging Science Experiment (HiRISE) camera and photographing larger swaths of terrain with its lower-resolution Context Camera (CTX). A color image from HiRISE, posted June 6 and taken in April, shows a large black-and-blue bruise on the landscape amid an otherwise flat area of red Martian dirt. Because MRO cannot look everywhere at once, it's unclear exactly when the new crater formed; the best estimate is somewhere between September 2016 and February 2019, scientists said. While MRO captures hundreds of these new dark smudges a year, said HiRISE team member and University of Arizona staff scientist Veronica Bray, this new crater is on the larger side of the ones that she has ever seen. That means the impact that created it was a fairly rare event, at least as far as we know from 13 years of MRO's continuous observing.
Bray estimated that the impactor responsible was about 5 feet (1.5 m) wide — so small that it would either have burst into pieces or eroded away completely had it come through Earth's much thicker atmosphere. The impactor might have been a more solid rock than usual, she added, because other rocks coming into Mars' atmosphere often shatter high in the air and create chains of craters as broken-up pieces smack into the terrain below. "It is a reminder of what's out there," Bray, a HiRISE targeting specialist who imaged this new crater, told Space.com. She said that Mars is a dynamic place, complete with shifting sand dunes and whirling dust devils, but she finds craters the most interesting Red Planet surface features. "It's a gorgeous [crater]. I'm glad I got it in the color strip," she said. Bray added that the color of this particular crater fascinates her, because she can see the impact wave clearly — a dark zone where dust was shifted off the surface. Beneath is likely basaltic rock, based on what we know of Mars geology and the colors showing in the image. There also are zones with a bluish tint, which may or may not be exposed ice. While the crater was blasted in the Valles Marineris region, near the relatively warm Martian equator, it's possible there could be a little ice underneath the dust, Bray said.
