The planet Mars does not bruise easily, but when it does, the result is practically a work of art. A fresh impact crater, spotted in April by the Mars Reconnaissance Orbiter (MRO), is unlike anything astronomers have seen before.
Remarkable for both its size and its impact waves, the black-and-blue mark stands out like a sore thumb on the planet's red, dusty surface.
The dramatic, enhanced-colour scene shown below was captured using NASA's High Resolution Imaging Science Experiment (HiRISE) camera, orbiting 255 kilometres away (158 miles).
(NASA/JPL/University of Arizona)
Each year Mars is bombarded by more than 200 asteroids and comets, and while some of these leave similar dark smudges or other remarkable features, University of Arizona planetary scientist Veronica Bray told Space.com that this new crater is one of the most impressive she's seen.
In the thirteen years that the MRO has been observing Mars, few events have compared. While the actual space rock fragment responsible looks to be about 1.5 metres wide (5 feet), the crater itself is much larger, roughly 15 to 16 metres wide (49 feet to 53 feet).
Such a tiny culprit would have probably burned up or eroded in Earth's much thicker atmosphere. Even on Mars, these incoming rocks can often shatter upon entry, creating chains of craters - like a machine gun pummelling the surface of the planet.
In this case, however, the rock must have been more solid than usual, because the entire thing managed to slam into one spot in the Valles Marineris region, which sits near the Martian equator.
"What makes this stand out is the darker material exposed beneath the reddish dust," explains the announcement on the HiRISE website.
Indeed, the impact wave is clear to see. This is the dark zone in the very middle of the image, where dust has been pushed aside to reveal the rocky surface underneath.
The exact nature of the geography in this region is still uncertain, but Bray says the surface below is probably basalt. And the blue in the image, she adds, is likely a bit of ice that was hiding under the dust as well.
KABOOM! Before and after images of a meteorite forming a brand new impact crater on Mars. Sometime between 18 Feb 2017 and 20 March 2019. pic.twitter.com/TWXtUoP5NA
— Peter Grindrod (@Peter_Grindrod) June 12, 2019
While the precise timing of the strike is unknown, astronomers think it was probably made sometime between September 2016 and February 2019.
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