When we talk of Mars, people generally think of it as a dead forsaken world with cold monster-looking aliens. Spoiler alert: Mars is way more subtle than you’d imagine (in comparison to Earth). Billions of years ago, it was different than it is today. It’s atmosphere was thicker and warmer, and probably had a moist surface. The planet’s atmosphere was largely lost due to solar radiation over the eons; and new research even suggest that the Red Planet might have been teaming with oceans and lakes.
Related media: Big Martian Lake!
Once Upon A Wet Mars
Roughly 4.2 billion years ago, Mars was pretty much better than it is today. The planet probably had an atmosphere, much thicker and moist than the Mars of today. The planet’s lack of a strong magnetic field has made it a victim of a runaway greenhouse effect. Unfortunately, the planet was robbed of it’s atmosphere over the next 500 million years due to all that solar radiation from the sun. And as a result, most of Mars’ water is trapped away in ice caps at its poles.
New research led by the University of Texas at Austin describes a Mars that had oceans and lakes that were constantly flooding the surface of the planet. The study which was titled ”Incision of paleolake outlet canyons on Mars from overflow flooding,” was published in the Journal Geology. The team examined the Martian topography with the aid of high-resolution photos taken by the National Aeronautics and Space Administration’s (NASA) Mars Reconnaissance Orbiter (MRO) of 24 paleolakes — craters on Mars which were once believed to be filled with water.
Scientists noticed in times past that many of these craters had outlets, ranging from several kilometers long and wide. They were uncertain about the formation of these craters — whether they formed over the course of eons, or were carved rapidly by floods. However, they were able to find a correlation between the size of the outlets and the volume of water expected to be released during large flooding events. These findings suggest that catastrophic geologic processes may have had a major role in shaping the landscape of Mars.
Don’t Blame It On Tectonics
“These breached lakes are fairly common and some of them are quite large, some as large as the Caspian Sea.” said Tim Goudge, a postdoctoral fellow from the University of Texas’ Jackson School of Geosciences (JSG), and the study’s led author, in a press release. “So we think this style of catastrophic overflow flooding and rapid incision of outlet canyons was probably quite important on early Mars’ surface.”
Here on Earth, there is a similar process that causes lakes to be filled by glaciers, and scientists are using the similarities to deduce what might have been the case of Mars billions of years ago. Here’s the catch: the rate at which these processes take place on Earth compared to Mars is the major difference. Here on Earth, the result of plate tectonics causes the changes in surface geology over time; whereas on Mars, being geologically inactive, it’s surface changes is as a result of massive floods and asteroid impacts.
“This tells us that things that are different between the planets are not as important as the basic physics of the overflow process and the size of the basin. You can learn more about this process by comparing different planets as opposed to just thinking about what’s occurring on Earth or what’s occurring on Mars,” as he indicated.
“The landscape on Earth doesn’t preserve large lakes for a very long time,” said Caleb Fassett of NASA’s Marshall Space Flight Center. “But on Mars … these canyons have been there for 3.7 billion years, a very long time, and it gives us insight into what the deep time surface water was like on Mars.”
Whence Crater Life?
The team also examined the Jezero Crater — the landing site of NASA’s Mars 2020 rover mission. This was to search for signs of ancient life on the planet, and surprisingly, they found that it held water for long periods in the past based on previous studies. In view of this, Jezero is considered as a hotspot in the search for evidence of extraterrestrial life on Mars, as well as the geological data that shows significant evidence of how its surface has evolved.
The crater is abundant with carbonate-bearing rocks and outcroppings of exposed clay minerals — the latter might likely be preserved with organics and other biogenic signatures. In addition, this study has provided insight (not the rover) on how catastrophic geological processes might have played in the surface evolution of Mars. These findings could also be applied to other worlds where tectonics activity is absent — which accounts for most discovery of exoplanets today.
Within the last decade, scientists have discovered much about the Red Planet — with several striking similarities between that of Earth. And they even expect to discover more in the coming years, such as whether or not Mars supported life, supports life, or would ever be habitable for humans.
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Written by: Nana Kwadwo, Mon, Jul 08, 2019.