Over the next decade, various space agencies plan to bring Martian rock back to Earth for the very first time – and, according to a new study published Tuesday in the journal Astrobiology, anyone who can analyze these precious samples one day might stumble upon something. . incredible: evidence of extraterrestrial life.
In a nutshell, a team of researchers says that if organisms really lived on Mars long ago, when it was an aquatic oasis, a bunch of them could have withstood the toxic transformation of the planet over the next few years. millennia, staying strong as this world became the desert we see today. But here is the kicker.
The researchers specifically suggest that any organism buried under the ground would have survived the longest, and therefore believe that the remains of these beings may still be hiding under Martian soil. As upcoming missions like ExoMars from Roscosmos and the European Space Agency are set to extract sediment from under the Martian soil, perhaps we will soon see groundbreaking extraterrestrial evidence.
“If Martian life ever existed, even if viable life forms are not now present on Mars, their macromolecules and viruses would survive much, much longer,” said Michael Daly, a pathologist at the Uniformed Services University of the Health Sciences and lead author of the study. said in a statement. “This reinforces the likelihood that, if life ever evolved on Mars, it would show up in future missions.”
And in fact, thanks to Daly’s experimental simulations, we may already know the name of the tiny organism (or at least its sibling) waiting to be forensically unearthed on Mars: Conan, that is- ie Conan the bacteria.
But more on Conan in a moment.
Also, as an important note, the team’s findings underscore that all future missions to Mars must exercise extreme caution. Basically, looking at the experimental results upside down leads to the knowledge that if we contaminate Mars with Earth bacteria somehow, perhaps from astronaut boots or scientific equipment, these microbes transmitted will not simply die. They could survive on the virgin planet for an excruciatingly long time.
“We concluded that terrestrial contamination on Mars would be essentially permanent – over time periods of thousands of years,” Brian Hoffman, a chemist at Northwestern University and co-author of the study, said in a statement. “This could complicate scientific efforts to search for Martian life.”
“Similarly,” he continues, “if microbes evolved on Mars, they might be able to survive to the present day. This means that returning samples from Mars might contaminate Earth.”
Time to blast organisms with extreme radiation
Despite humanity’s burgeoning excitement about settling on Mars, the planet (as we know it now) doesn’t seem to want to settle down.
It has virtually no air, constantly experiences frightening cosmic ray flashes, and boasts temperatures comparable to the coldest Antarctic winters.
Thus, it is rather doubtful that any life that could have existed on Mars managed to leave traces of itself easily visible today. Presumably, most of its fingerprints — molecules, viruses, or other bits — would have simply vanished alongside the planet’s descent into habitability.
“There is no running water or significant water in the Martian atmosphere, so cells and spores dry out,” Hoffman said. “The surface temperature on Mars is also known to be roughly similar to dry ice, so it is indeed deeply frozen.”
This annotated image of Mars shows the area where water ice is near the surface.
NASA/JPL-Caltech
The goal of the study by Hoffman, Daly and others was to alleviate some of that skepticism. Or in other words, they asked: what is the realistic probability that our expeditions to Mars will find evidence of extraterrestrial life?
To answer this question, the team first determined the relevant radiation survival limits of microbial life in general. Next, they exposed six types of Earth bacteria and fungi to a simulated Martian terrain and fired things like gamma rays and fast-moving particles at the organisms to mimic cosmic radiation levels on Mars’ surface.
In short, the researchers concluded that some surface-based beings could potentially survive in the harsh climate of Mars for hundreds of millions of years.
Which brings us back to Conan the Bacteria.
Also known as Deinococcus radiodurans, the microbe dubbed Conan the bacterium seemed particularly well adapted to the extreme conditions encouraged by the team, surviving what the researchers call “astronomical amounts of radiation in a freezing, arid environment.”
But the likelihood of finding Martian life skyrockets when we take things underground. Even for Conan.
D. radiodurans (affectionately known as Conan the bacterium) is uniquely adapted to survive the harsh environment of Mars.
A microscopic image of Conan the bacterium. It looks like some kind of 2D spherical drop, red-orange, stained, on a yellow surface.
Inside Martian Underground Culture
The second part of the team’s latest experiment involved exposing organisms to subterranean levels of radiation as well as Deep underground radiation levels on Mars. As expected, the samples appeared to exhibit much greater survivability in both cases compared to full surface radiation.
Conan the Bacterium actually broke its previous record.
Previous studies have shown that this microbe survived 25,000 units of radiation when suspended in liquid, but when testing Conan in a dry state, as the new study did, the microbe could withstand 140 000 radiation units. That’s 28,000 times more than what would kill a human.
In terms of survival lengthhowever, these figures suggest that Conan could have lived 10 centimeters below the Martian surface for 1.5 million years and 10 meters below the surface for 280 million years.
A landscape from Mars shows a layered cliff with a nearby small boulder impressively balanced on top of a larger boulder.
NASA/JPL-Caltech/ASU
And even more promising is the thought of Mars going through some sort of intermittent melting and freezing over time, which would further help strong bacteria like Conan thrive in the evolving world.
“Although the D. radiodurans buried in the Martian subsoil could not survive in dormancy for the estimated 2 to 2.5 billion years since the disappearance of running water on Mars, these Martian environments are regularly weathered and melted by meteor impacts,” Daly said. “We suggest that periodic melting might allow for intermittent restocking and dispersal.”
All in all, there’s a good chance of ancient Martian bacteria lying just below the Martian surface, soon to be unearthed by humans – with care, of course. Otherwise, our pursuit of extraterrestrial life might accidentally leave a microbial imprint that projects a terrible butterfly effect through space and time.
