NASA continues its search for life on Mars. But in order to do so, experts need to understand better what they are looking for. Australia’s stromatolites, the oldest confirmed fossilized lifeforms on Earth, may offer some insights on what we can find in the Jezero Crater on the Red Planet.
In July 2020, NASA and its European counterpart – The European Space Agency (ESA) – will join hands to launch two new rovers on Mars. The agencies’ shared purpose is to search for life on Mars. Specifically, the rovers will look for signs of past microbial life on the Red Planet in the Jezero Crater.
Interestingly enough, to understand what they are looking for, scientists have to, once again, travel the Earth to find life on Mars. Just as the ARDAS digs in the Atacama desert, geology and biology experts visited Australia to study stromatolites. These structures contain fossilized records of ancient microbial life and they are without a doubt the oldest such “archives” on our planet.
On Mars, scientists got intel about the existence of distinct deposits of minerals (carbonates) along the inner rim of Jezero Crater. On Earth, carbonate deposits can form structures resilient enough to survive as fossils for billions of years. One such type of fossil form – besides coral or seashell for instance – is stromatolite.
And when can scientists analyze stromatolites first-hand? In the Pilbara region of northwest Australia!
NASA’s & ESA’s Search for Life On Mars Next Year is the SCI-FI Novel that Writes Itself
If there ever was Martian life on the famous Red Planet, NASA and ESA want to find it. The two rovers and two missions planned for launch next year will try to study closely the Jezero Crater. According to a study published in the journal Geophysical Research Letters,
Silica has the highest demonstrated potential of any phase to preserve microfossils on Earth and therefore may host potential biosignatures on Mars. We detected hydrated silica in Jezero crater, the landing site of NASA’s Mars 2020 rover mission […]. We assess the likelihood of silica to preserve biosignatures in these different scenarios based on habitability considerations and biosignature preservation in Earth analog environments and materials.
The two rovers will reach Mars’s surface in 2021. While they are looking for the same thing, each mission will approach things in their manner.
The NASA Mars 2020 rover will drill many shallow holes to collect over 40 soil and core samples. Then, the rover will safely deposit some of these samples on specific sites. The idea is that future missions to go to Mars and retrieve the samples for a detailed analysis that is currently impossible to conduct on the Red Planet.
The ESA’s rover – named Rosalind Franklin – carried a powerful core drill that will dig one or two holes into the Martian crust, but at greater depths (around 7 feet/2 meters). The rover will then analyze the collected samples on-site with the help of the advanced (futuristic if you ask us) instruments that are part of its equipment.
But Why Did the Scientists Go to Australia to Search for Life on Mars?
Last year, two teams of scientists from NASA and ESA went to Australia in the Pilbara region to study and debate the stromatolites found in the Dresser Formation.
Between 3 billion and 4 billion years ago, the Jezero Crater on Mars seems to be the confluence of a river that flowed into a lake the size of Tahoe. The river deposited delta sediments rich in clay and carbonate minerals. According to the scientists, these represented the ideal conditions for the formation of stromatolites on the lake’s (now a crater) shoreline. It is the main reason why the Mars 2020 rover will be landing here in February 2021.
A recent study published in the journal Icarus highlights the importance of carbonates on the Jezero Crater’s shoreline:
Thus, Jezero crater may contain a unique record of the evolution of surface environments, climates, and habitability on early Mars.
What Is With Australia Then?
Simply put, the two space rovers will be looking for very special types of rocks – stromatolites. Similar stromatolites are down here, in Australia, and scientists went to learn more about them. The key reason why they did this is that the events that occurred in the Dresser Formation around a billion years ago and what happened on Mars roughly at the same time share some bizarre and thought-provoking similarities.
According to Martin Van Kranendonk – director of the Australian Centre for Astrobiology at the University of New South Wales – the Pilbara region resembles the Jezero quite well – from a historical point of view at least:
Some 3.48 billion years ago, this area was home to a caldera, or collapsed volcano, filled with hot, bubbling seawater. At the same time, this location was also home to structures called microbial mats — visible to the naked eye but composed of microscopic organisms. Today you would know them as simple pond scum, but back then they were the most complex lifeforms on Earth.
The rocks spotted around Jezero show evidence of carbonate and hydrated silica. As we said, on Earth, these molecules are known for preserving microscopic fossils for billions of years. While the expedition in the Pilbara region has ended, the science teams from NASA and ESA are now further developing their stromatolite-hunting skills in preparation for next years’ missions.
What Will the Search for Life On Mars Reveal?
Don’t keep your hopes up if you don’t want a heartbreak. While scientists on both teams are excited to analyze the Jezero Crater, their findings should be not only concludent, but extraordinary (to paraphrase Carl Sagan). A grain of salt is necessary. There is no guarantee that the Jezero carbonates were formed in the lake. However, the very research of the Jezero Crater floor and delta is an amazing feat.
According to Mars 2020 Deputy Project Scientist Ken Williford of NASA’s Jet Propulsion Laboratory in Pasadena, California,
The possibility that the ‘marginal carbonates’ formed in the lake environment was one of the most exciting features that led us to our Jezero landing site. Carbonate chemistry on an ancient lakeshore is a fantastic recipe for preserving records of ancient life and climate. We’re eager to get to the surface and discover how these carbonates formed.
Looking for carbonates and hydrated silica – the other mineral great at preserving signs of ancient life – is something to look out to, especially since science-fiction literature got us used to the idea that the Martians will come here first to study us. Now, we are going to try finding signs of microbial life under Mars’s crust.
Will there be any?
This is Just The First Step in Our Search for Life on Mars
The Martian carbonates may still hold signs of ancient life on the planet. The hydrated silica – never found until now – so close to the Jezero delta may contain biological material from the ancient river (similar to the one found in Australia). Such samples could very well show remains of ancient organisms still trapped in the minerals. But they won’t show, without any doubt, that Martians ever existed.
The entire process will take years, if not decades. No one approved – nevermind budget and develop – the further missions on Mars to collect the samples from Jezero. Nobody built yet the hi-tech facility equipped with the neccesary cutting-edge tech to analyze the stromatolites to finally conclude whether there was life on Mars or not. It may never happen. However, if all goes according to plan, the two space missions will touch the Jezero area next year.
And then, space exploration and astrobiology will enter a new era, where no man has ever been before.
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