Mars Didn’t Just Have Oceans, It Had Mega Tsunamis

The sci-fi movie of 2019 The wave (now streaming on Peacock!) follows the incredible exploits of Frank – unnamed – played by Justin Long. He’s not a likable character per se, despite Long’s particular charms, reveling in denying an insurance claim and reaping the financial rewards he will reap. During a night of partying, after managing to find a way to deny the insurance claim of a firefighter who died of a heart attack, Frank is exposed to an unnamed hallucinogen and immediately passes out.

When he wakes up the next day, he is treated to a drug-induced high-flying adventure that changes the way he sees the world and his place in it. It is essentially a modern account of A Christmas Carol but with many more drugs. Frank’s metaphorical wave may have seemed out of this world, but it can’t compare to the truly devastating mega-waves that rocked Mars 3.4 billion years ago.

This was during what is called the Hesperian period on Mars, a period of about 800 million years, dating from 3.7 to 2.9 billion years ago. It was a period of intense change, following the heavy bombardments of the previous Noachian period. The impacts slowed down, although they didn’t completely stop, more on that in a minute. Instead, the Hesperian was dominated by intense geological and environmental changes on Mars. Volcanism was slowing, though still pouring sulfur and water into the environment, and the planet was cooling. Much of its liquid water, which may once have been deep enough to cover the entire planet in an ocean 300 meters deep, was locked underground or in permafrost. When an impactor struck the planet, however, the water locked underground erupted in incredible flash floods that swept across the Martian landscape.

In 1971, NASA sent its Mariner 9 spacecraft to the Red Planet, which discovered the first evidence of fluvial landscapes – fluvial refers to landscapes shaped in part by waterways like rivers and streams – and this discovery has dominated the exploration and study of Mars ever since. , thanks to the exciting potential of the existence of ancient Martian life. A few years later, NASA sent its Viking 1 lander to Maja Valles, an escape channel in Chryse Planitia.

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Unfortunately, the sightings of Viking 1 were difficult to explain. The landing site was supposed to be a spreading dump, but it lacked the features the scientists expected to find. For years, the origin of Viking 1’s landing site features remained a mystery. Some have speculated that the site may have once stood near the margins of an ancient sea, and its unusual features may be the result of a mega tsunami caused by an asteroid impact.

That’s where scientists from the Planetary Science Institute, the NASA Ames Research Center, the University of Arizona, and colleagues around the world come in. They continued the work started by Mariner 9, in a new article published in the journal Scientific reports.

A mega tsunami caused by an impact matched Maja Valles’ observations, but scientists had to find the smoking gun, or rather the planetary bullet hole. They scoured maps of Mars for a suitable impact crater and found one that could have been the site of an ancient impact followed by a devastating mega wave.

The crater, nicknamed Pohl, is about 900 kilometers from Viking 1’s landing site, but it turns out it’s pretty close, as long as your tsunami is strong enough to reach it. The impact crater is 110 kilometers in diameter, which is more or less comparable to the crater left after the destruction of the dinosaurs.

The researchers attempted to disassemble the asteroid itself from the impact crater and came up with two possibilities, both of which depend on the overall strength of the impacted sediments. Simulations show that a 3 kilometer object hitting relatively soft ground, or a 9 kilometer object hitting denser terrain, moving at a speed of 10.6 kilometers per second, would have been enough to carve out a crater 110 kilometers.

The simulations feature a devastating natural disaster with crustal material ejected several kilometers into the extraterrestrial air and waves hundreds of meters high. According to recreations, the waves are believed to have decreased in height relatively quickly while carrying their kinetic energy to distant locations. Not only was the impact and subsequent tsunami powerful enough to reach Viking 1’s landing site 900 kilometers away, but scientists estimate that the waves would have traveled almost twice that distance, dying out at around 1,500 kilometers from the impact site.

Had there been budding life trying to cling to this primeval Martian landscape, the impact and tsunami would have made for a particularly bad day. At least Mars didn’t have dinosaurs – as far as we know! — microbes get up a little easier than 20-ton sauropods. If we’re lucky, we’ll find out once and for all if Mars had any creepy creatures in its distant past, when rock samples from the Perseverance rover return to Earth in the 2030s.