Once you see it, you can't shake it; there is indeed an elephant on Mars! Well, it's actually a Martian lava flow in the shape of an elephant's head, but it is also a fantastic opportunity to discuss some Mars geology and why the human brain seems so easily tricked into seeing large mammals in alien landscapes.
First, a little Mars geology.
As photographed by the High-Resolution Imaging Science Experiment (HiRISE) camera aboard NASA's Mars Reconnaissance Orbiter (MRO), this geological feature was spotted in Elysium Planitia, a Martian plain that exhibits some of the youngest lava flows on the Red Planet's surface.
Mars is largely geologically inactive, so active volcanoes and flowing lava are a thing of the past. But the ‘young' lava flows that cover Elysium Planitia may have been emplaced within the last 100 million years - potentially as recent as the last 10 million years. This may not sound recent, but when chronicling billions of years of Mars geological history, a hundred million years is no time at all.
According to University of Arizona planetary geologist Alfred McEwen, when the lava flow was hot and spewing out of Mars' interior, its advancing flow front would have most likely been so slow that an elephant could have out-walked its glacial pace - not too dissimilar to lava flows on Earth.
"However, there is also evidence for much more rapidly flowing lava on Mars, a true flood of lava," McEwen points out. "In this instance, maybe this elephant couldn't run away fast enough."
Whether or not an elephant could outrun a lava flow on Mars isn't the focus of this HiRISE photograph, however. It's actually a vivid example of "pareidolia" - a psychological phenomenon that tricks our brains into seeing familiar objects in random shapes.
A popular everyday example of pareidolia is seeing shapes of bunnies in clouds. But pareidolia can take on all shapes and sizes (pun intended). People see religious symbols in potatoes and "Angry Birds" in astronomical observations of deep space. What about the "Man in the Moon"? Yep, that's pareidolia. So is the "Face on Mars" that was captured by early observations of the Red Planet (and spawned the punchline of the terrible Hollywood movie "Mission to Mars").
Mars is often the subject of some great popular culture pareidolia, like the "Martian Yeti." Surface missions to Mars often come under close scrutiny after conspiracy theorists and the tabloid press interpret random shapes in rocks as being somehow artificial.
While writing about an apparent "Egyptian statue" carved into the side of a rocky outcrop at Victoria Crater as photographed by Mars Rover Opportunity, I decided to go on a "pareidolia hunt" of my own. Taking the Opportunity photo (including two "alien artifacts" as detailed on conspiracy websites - pictured below), I used a bit of imagination and spotted a huge number of shapes that looked familiar. (I was particularly impressed to see "Star Wars" Admiral Ackbar etched into one outcrop.)
So it goes to show, whether you're orbiting Mars or roving across its surface, there is an endless supply of randomly shaped rocks and geological features to trick your brain into thinking its seeing elephant heads. But also watch out for those pesky cosmic rays, they might give you the impression that we already have bases on Mars.
Image credits: NASA/JPL/University of Arizona