For centuries, humans have struggled to answer the question, “Are we alone in the universe?” The discovery of methane gas in the Martian atmosphere this past March by the Mars Express orbiter may bring scientists one step closer to being able to answer that question.
This discovery has set off a wave of excitement in scientific circles around the world, but nowhere more so than in the laboratory of Univeristy of Arkansas biology professor Timothy Kral. For years, Kral and his team of researchers at the Arkansas-Oklahoma Center for Space and Planetary Sciences have been exploring the possibility that the Red Planet could sustain life.
“This discovery is a tremendous boon for us,” Kral noted, “because it supports the very work that we’ve been doing.”
Kral and his colleagues recently published a paper detailing their work with a class of organisms known as methanogens — methane-producing organisms that some scientists believe may hold the key to whether or not Mars conditions can support life. For the past several years, Kral and his colleagues have been testing the organisms’ ability to survive under Mars-like conditions.
“This paper is the product of four years of intensive research, so we’re very proud of it,” he noted. “And with the simultaneous discovery of the methane in Mars’ atmosphere, this research becomes even more significant.”
Methanogens are found in nearly every anaerobic environment on earth, from hot springs to the deep ocean to the intestinal tracts of humans and animals. Methanogens do not require oxygen to survive; instead, these tiny creatures breathe carbon dioxide and hydrogen gas, producing methane as a waste product. This unique form of respiration makes methanogens potentially viable residents of Mars, whose atmosphere is predominantly composed of carbon dioxide with practically no oxygen.
To test the creatures’ ability to survive on the forbidding planet, Kral and his research team had to find a way to recreate the Martian environment in the laboratory. They did this using a specialized vacuum system known as the Andromeda Chamber. The chamber was filled with a Martian soil simulant that the researchers obtained from Hawaiian volcanoes. This simulant mimics Martian soil in composition, grain size, density, and magnetic properties, making it a superb medium for carrying out their research.
“With the Andromeda Chamber, we can recreate conditions on Mars and then see if the methanogens can survive,” Kral explained. “We can lower the atmospheric pressure to the same as is found on Mars, which is approximately one-one hundred and fiftieth that of earth’s. Although we haven’t yet taken them down quite that low, under our current conditions they are growing and still producing methane.”
Methane, a gaseous compound of carbon and hydrogen, is unstable in the presence of ultraviolet sunlight and can be completely destroyed from the atmosphere in only a few hundred years. Its presence, then, in the Martian atmosphere can only be explained if there is some process on Mars that is continually creating it.
Two potential scenarios could explain the presence of the gas, Kral said. Either the methane is being produced by living organisms, which would mean that some type of methanogens already inhabit the planet, or the methane is being made below the planet’s surface by subsurface volcanic activity. The presence of such volcanic activity would mean that there is a source of energy and warmth below the surface — two factors that are indicators that liquid water may also exist below the surface.
“For us, this is a win-win situation under either scenario,” Kral said. “Either the methane is being produced by methanogens that already inhabit the planet, or there is volcanic activity, which means warmer conditions exist that could support life.”
If life could exist, or already exists, on Mars, the implications for the inhabitants of Earth remains a source of heated debate. Many scientists believe that, if life does exist on the Red Planet, it should be left undisturbed, while others propose using the planet’s potential to sustain life for the benefit of humans.
One of the more extreme suggestions that has been proposed is the idea of “terraforming” Mars — making it into another livable environment for humans. This idea is decried by many in the scientific community as unethical, since it would involve colonizing another planet for the sole purpose of using its resources and potentially destroying it.
Another, less controversial, idea supported by some scientists, is for humans to promote the process of eco-synthesis on Mars, which would involve encouraging conditions on the planet conducive for any organisms that already inhabit it to flourish.
“Speculation among some scientists is that there is life there now that at one time was thriving, but that some environmental change occurred that altered the conditions on the planet. If we could make it warmer or somehow encourage the creation of a thicker atmosphere, it could allow life to thrive again as it once did,” Kral explained. “And this would be more ‘natural’ than having humans simply ‘take over’ the planet.”
Whatever the future holds for Mars, though, just the knowledge that life, or the potential for life, exists there could create changes felt around the world and beyond.
“If we were to discover that we’re not alone, that knowledge would create a major paradigm shift in so many areas — from philosophy to sociology to psychology — the list goes on and on,” Kral said. “It’s a very exciting thought.”
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