A Perseid meteor streaks across the sky above Inspiration Point.

Alien Extremophiles Could Live High In Planets’ Atmospheres

“Extremophiles” are organisms that live in, as their name suggests, extreme environments that other forms of life have proven incapable of living in. Tardigrades, or “water bears,” which can survive in both extreme heat and extreme cold, as well as high pressure, are among the most commonly referenced extremophiles.

Some species found at the deepest depths of the ocean are considered extremophiles, but researchers are also increasingly interested in discovering what types of life can exist at the highest altitudes of the Earth’s atmosphere — and perhaps the atmospheres of other planets in our solar system.

Researchers based out of the University of Houston will visit Alaska in March to conduct experiments to try to determine if microbial life is prospering at altitudes of 11 to 31 miles above the Earth’s surface.

The researchers will be using a balloon-like instrument to catch air, and hopefully microbes, to bring them back down to Earth for study.

“The instrument, which looks almost like a small laundry hamper, pops open to collect what’s in the atmosphere,” Elizabeth Howell writes in an article for Space.com. “Then, as the balloon descends, it shuts closed for researchers to analyze.”

One question the researchers have is whether or not microbials that drift up into the atmosphere can thrive there or if the extreme conditions end up being to much for them to survive.

“A lot of times, these microbes when they go up there, they shut down,” Jamie Lehnen, one of the researchers from the University of Houston, told Howell. “They are not replicating and they are not metabolically active. I’m interested in how their stress response is similar to those [microbes] back on Earth’s surface.”

Lehnen and her colleagues are carrying on a nobel scientific tradition of searching for extremophiles and other microbes. As Howell notes, Darwin once found microbes in dust that had been carried on to his ship during a stopover in Africa, and Louis Pasteur studied the growth of microbes, or lack thereof, in several environments, including alpine glaciers. Charles Lindbergh took air samples while in long flights at high altitudes and supposedly discovered pollen and mold spores there.

The significance of the University of Houston researchers’ studies could extend well beyond Earth. For many decades astronomers and other scientists have wondered about the possibility of microbial life on both Mars and Venus, as well as other planets in our solar system.

“Back in the 1960s, astronomer and science popularizer Carl Sagan suggested that the upper atmosphere of Venus could harbor the descendants of organisms that could have evolved on the surface of the planet when it was cooler,” Howell writes.

“Even though today the surface can crush and cook unprotected spacecraft, 50 kilometers (31 miles) above is more temperate. Moreover, researchers have found an intriguing substance that blocks ultraviolet light in Venus’ clouds. Life hasn’t yet been ruled out as a possibility.”

The atmosphere and geography of Earth and Venus were very similar for hundreds of billions of years, perhaps up to as recently as 500 million years ago, Howell says. That leaves a considerable window for microbial life to have evolved to adapt to Venus’s changing, and now extreme by our standards, environment.

If the researchers do discover extremophiles living high above the Earth, it could pave the way for more research into the possibility of alien life in the atmospheres or beneath the surfaces of planets and other bodies throughout our solar system, perhaps even in the underground ocean recently discovered on Pluto. You won’t find a more extreme alien environment than that this side of the Kuiper Belt.

[Featured image by Ethan Miller/Getty Images]

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