According to a new study, by observing microbial life that lurks in the stratosphere of Earth, scientists may be edging closer to understanding how a very different and extreme type of life may be hiding in plain sight on other planets.
The stratosphere of Earth can be found sitting on top of its troposphere, yet the life that could be living in this area is still very much a mystery to scientists. But according to University of Maryland microbiologist Shiladitya DasSarma, there are a mind-boggling number of micro-organisms to be found in the lowest level of the Earth’s stratosphere that we do know about, in the region where airplanes routinely cruise above 35,000 feet, as Space reports.
“Generally, people don’t think of microbes being airborne. But there’s a saying in microbiology: Everything is everywhere.”
However, when it comes to understanding the atmospheric biome, DasSarma noted that there are unfortunately “very few studies at the present time.”
Priya DasSarma, another research scientist from the University of Maryland, explained that part of the reason for this is due to just how staggering the vastness of this space would be.
“When you’re talking about the entire atmosphere of a planet, how do you do a survey of that?”
If scientists did choose to conduct an exhaustive study of Earth’s stratosphere, Priya suggested that it would have to be one that was incredibly in-depth, explaining that this research would be extremely worthwhile.
Not only would studies of this kind help us to understand more about extreme types of life on Earth, but it would also go a long way to showing us how cells could find a way to survive in the harsh climates of other planets, something NASA microbiologist David J. Smith agrees with.
“When we measure the response of terrestrial life in extreme environments on Earth, we can learn more about habitability across the Solar System and where to refine the search for life elsewhere.”
Surviving in the hypobaric, ultraviolet stratosphere would certainly be a difficult task, which is perhaps why it is such a good reason to learn more about it if we are to ever locate life in a similar location in other worlds. Mars, for instance, has a very similar stratosphere, as Shiladitya DasSarma noted.
“The temperatures, UV and dryness are similar to Mars, so it’s a great proxy There’s a wide variety of stress-survival mechanisms. For UV, a number of extremophiles have DNA damage-repair mechanisms. Others have additional, more quiescent methods, like extreme halophiles that can survive very low-water situations because their proteins are designed to hold onto whatever small amount of water is present.”
If life was somehow able to survive and thrive in the stratosphere, then it is certainly feasible that it may also have adapted the ability to survive in space.
There is also the possibility that microbes that may be “hitchhiking” on spacecraft could survive their journey through space and onto other planets, but NASA have a rule that no other planets should be exposed and contaminated by microfauna from Earth. Smith addressed this very subject in a study in 2017.
“We know Mars is a dusty planet, and spacecraft coated in dust might shade some microbial hitchhikers. Also, a portion of bioburden are embedded deep inside the spacecraft’s hardware where they are protected from radiation, substantially reducing or completely eliminating the effects of UV.”
It is important to remember that although microbial life may indeed be able to survive in harsh climates, it doesn’t necessarily mean it could end up reproducing. This is why studying these extremophiles in our own stratosphere is key to understanding its potential on other planets. Also, if we are ever to colonize other planets like Mars, having good bacteria around will be important, as Priya DasSarma confirmed.
“If we want to go to Mars and inhabit it, we are going to want to bring whatever microbes and macrobes with us that we need to survive there. But we don’t want to bring anything that contaminates or destroys the environment that we’re going to.”
Despite the enormity of such a task, starting a new research project on extreme life hidden in Earth’s stratosphere would be immensely helpful for us in the future if we would like to recognize life on other planets when we see it.