The existence of microbial life within the Earth’s stratosphere broadens the potential for stratospheric extraterrestrial life on exoplanets. At least, this is the outcome of a recent research that synthesizes what we currently know regarding the stratospheric life and which has been issued in the journal Current Opinion in Microbiology.
The stratosphere represents the layer of atmosphere that is immediately above the troposphere which is the one where we live. However, the stratosphere remains an enigma for scientists in terms of the life forms that might live there.
“You may not notice it when you look out the window of a plane but there are all kinds of microorganisms,” explained Shiladitya DasSarma, a professor and a microbiologist from the University of Maryland.
Despite the fact that scientists believe there is life in the Earth’s stratosphere, not many studies have been carried out to examine precisely what kind of microbial life is out there. What is known is only an estimate that there are about 1021 living cells in the atmosphere.
Stratospheric life on Earth encourages the search for extraterrestrial life on exoplanets
Following the model of the Earth where microbial life exists in the stratosphere, scientists are optimistic that exoplanets might also present similar characteristics. However, the search for stratospheric extraterrestrial life would be a very complex procedure and since we can’t go there and take samples, the search would be based only on the readings of the space telescopes.
“A program like that would be incredibly productive, interesting and valuable, not only for what it could tell us about life on Earth but also for how cells could survive and even adapt to life on other planets,” said Professor DasSarma.
DasSarma added that the Earth’s stratosphere present identical conditions to those on the surface of Mars but life still persists there as bacteria and even fungi adopt various strategies to survive in the dry, cold and low-pressure environment of the stratosphere.
According to the scientists, if some life forms can live in such harsh conditions, then exoplanets might also house stratospheric extraterrestrial life.