Craters on Mars

Mars Hit By Meteorite ‘Shotgun Blast’

Planet Mars is not as well protected against incoming meteors as Earth, and NASA has recent photo evidence to prove it. In fact, the meteorite damage done to the surface of Mars has been likened to a “shotgun blast.”

Seeker reported this week that NASA’s Mars Reconnaissance Orbiter (MRO) detected evidence that the Red Planet’s surface had suffered an impact, capturing an image of a fairly large cluster of dark anomalies. But the cluster turned out not to be a single meteorite impact. Instead, it was dozens.

Unlike the Earth, which has various layers — and miles — of atmosphere, Mars has a very thin protective sheathe encircling the red globe. So when an average-sized meteor enters the Martian atmosphere, it gets very little resistance (more if the meteor hits at an angle to the surface) as it passes through. While on Earth a meteor would break into smaller pieces and burn up in the atmosphere, with only the more dense pieces making it through as impactors to the surface, a meteor might or might not break up in the thin Martian atmosphere and far more of the material will ultimately strike the surface.

Part of the MRO’s ongoing mission has been to track fresh impact sites on Mars’ surface. In this particular case, scientists were able to use the orbiter’s Mars Context Camera (CTX), the instrument that originally detected the impact site, to determine that the impact must have occurred between 2008 and 2014. That same detection prompted a follow-up fly-by where the High-Resolution Imaging Science Experiment (HiRISE) camera was able to distinguish two large impact craters and about 30 smaller craters across the crater in the Tharsis region of the planet.

As noted, the darkened areas on the planet’s surface looked more like shotgun blast than it did a single large-impact hit.

Mars in space
Mars has nearly no protective atmosphere. [Image by manjik/Shutterstock]

Not only will the (relatively) new meteorite site provide plenty of data for planetary scientists to work with, the impactors will serve as cautionary markers to NASA and other space agencies planning manned missions to Mars in the future. The missions will have to factor in the dangers of a meteor strike on any stationary (or mobile, for that matter) element, habitat, or structure being used. In fact, given the new space race to Mars that includes private companies like Elon Musk’s SpaceX and national space agencies from countries like the United States and China, there is every indication that one or more of the missions will attempt to place a permanent base on the Red Planet.

As Seeker pointed out, the thin atmosphere on Mars would allow for far more of the meteors to make it to the Martian surface, even if it were to break up like the recently discovered impact site revealed. The difference, of course, is that of being hit with a single projectile as opposed to dozens.

Future missions would stand a far better chance withstanding the impact of a single meteorite than they would the scatter-shot effect of dozens. And given the harsh radiation that burns Mars continually (another by-product of a thin, non-protective atmosphere), securing safety against a meteor strike will likely push plans for future Mars colonies to place most — if not all — of the installations underground.

Concept of a Mars base
Given the dangers of a meteor strike and the harsh radiation, concepts of a Mars base being above ground ultimately may be shelved. [Image by Sebastian Kaulitzki/Shutterstock]

Meteors sometimes make it through Earth’s atmospheric shield relatively intact — or at least intact enough to cause a bit of damage. Take, for instance, the detonation of the Chelyabinsk meteor in the atmosphere over Russia in February 2013. reported in November 2013 that the deterioration of the meteor produced a massive shockwave equal to the energy of about 30 atomic bombs like the one dropped on Hiroshima in World War II. Numerous meteorites from the space rock have been found, including one meteorite that, according to the New York Times, weighed more than 1,250 pounds.

Fortunately, that meteorite was retrieved from a lake, because on Earth or Mars, being in the impact zone of a massive space rock like that would be problematic.

[Featured Image by Jan Kaliciak/Shutterstock]