HiRISE Spies a Young Martian Crater

By now folks used to reading about Mars have gotten pretty spoiled by the amazing images from the High Resolution Imaging Science Experiment (HiRISE) aboard the Mars Reconnaissance Orbiter.

This fabulous camera came online in 2006 and returned its first color images of Mars in 2007.

The current catalog of more than 8,700 images is a study in how science can become art—rippling sand dunes and scalloped craters in gentle hues of blue and red can look more like exhibits at the MoMA than data on planetary geology.

So at first blush it can be a bit of a downer when a HiRISE image looks like this:


—Image courtesy NASA/JPL/University of Arizona

But hey, this is a science experiment, and this contrasty crater is just busting with science.

HiRISE snapped the image on November 1, 2008, showing Mar’s northern lowlands, which appear to be plains of ancient lava flows resembling Earth’s ocean basins.

NASA describes the crater in the new image as “young” and “fresh”—terms that need some perspective to appreciate.

HiRISE principal investigator Alfred S. McEwen tells me that a predecessor camera on the now-defunct Mars Global Surveyor saw the same crater (albeit at lower resolution) in 2003, which means the feature is at bare minimum five years old.

“Given its fresh appearance it probably isn’t older than ~1 million years,” he told me in an email. And on a cosmic scale, a million years is like the blink of an eye.

It’s even cooler when you consider that we’re pretty sure craters this size form on Mars just once in a millennium, so it’s quite the newcomer as Martian features go.

The HiRISE caption notes that the crater is about 984 feet (300 meters) across, and it was likely formed by an asteroid less then 65 feet (20 meters) wide.

The high-res view reveals a surprising number of boulders around the crater, both near the rim and rolled inside. The largest of these boulders are bigger than family sedans—29 to 33 feet (9 to 10 meters) across.

In black-and-white, the dark ejecta stand out against the dusty Martian surface and the thin layer of dust that’s accumulated inside the crater’s bowl.

Smoother, more filled-in craters surround the newbie, giving a good visual of why we think high color contrast + lots of well-defined rocks = young in crater-speak.

According to McEwen, very young craters like this would be attractive places to set down a lander, as they could help us better understand the nature of Mars’s lava plains.

For example, looking at freshly turned-up rocks in these northern lowlands could offer convincing evidence for whether the red planet once had an ocean of its own.