In 2007, before we knew much of anything about Mars, a stereo anaglyph showed what appeared to be a landslide. Now, the Mars Reconnaissance Orbiter has finally confirmed the stereo image with this new photo of the surface.

In geology, the term “mass wasting” refers to the downhill movement of sediment. Mass wasting could be in the form of an avalanche, landslide, or debris flow. These events are usually the result of water movement in an area, which, when combined with gravity causes the land to give away.

So, when evidence of a landslide was found on Mars 10 years ago, it was a signal that there was once or still is water on Mars. The remnants of the landslide can be found on the edge of a cliff called Simud Valles, which is in the Xanthe Terra region. The Xanthe Terra once had a vast network of channels, which would have likely caused some kind of erosion to the Simud Valles that created this vast landslide.

Mars landslide topography
 A stereo anaglyph of an ancient landslide taken in 2007. 

Another interesting finding was that the large boulders on the surface of the landslide suggest that they weren’t broken down when falling off the cliff like they do on Earth. This would be in line with the lighter gravity on Mars, which is about 38 percent that of Earth’s. So, when heavy objects fall, it’s a much softer landing.

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Mars topography
An orbital image matches a 2007 stereo anaglyph of a landslide.

There is evidence of ancient waterways all over Mars. In the Kasei Valles region, there was believed to be a huge flood plain where water created craters that are up to 15 miles wide. Scientists also found evidence in the Lucaya crater, which they believe was once flooded with salty water.

Of course, humans won’t know if their red neighbor once hosted life until we arrive. But, there is enough mounting evidence to prove that Earth might not be the first or last hospitable planet in the solar system.

Photos via MRO/NASA, NASA/JPL-Caltech/Univ. of Arizona