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(Picture for representation) Enceladus might be the home of aliensNASA/JPL-Caltech/Space Science Institute

Scientists were left surprised when a recent study indicated that methane found on Saturn's moon Enceladus could be a byproduct of alien activities. To be more precise, they think alien microbes might be emitting methane gas.

Researchers came to this conclusion after conducting lab experiments on some microbes that can survive in extremely tough conditions like the freezing environment of Enceladus, the sixth-largest moon of Saturn with a diameter of 500 kilometers (310 miles). 

These experiments showed that these microbes were feeding on hydrogen to produce a biological byproduct, which is methane. On Earth, such methane-belching microbes crawl hydrothermal vents and are known as methanogens.

This work has been published in the journal Nature Communications.

The research team, led by Simon Rittmann, a microbiologist from the University of Vienna, cultivated methane-producing archaea — a type of single-celled microorganisms that is known to churn out methane from carbon dioxide and hydrogen gas, reported the website.

They put these organisms in 120-milliliter bottles with different compounds and gases. Some of them were even pressurized to mimic the oceans of Enceladus.

Mimicking the conditions on Enceladus was challenging for the researchers as very little is known about its oceans.

What stood out after the experiment was that a microbe named Methanothermococcus okinawensis flourished in Enceladus-like conditions and survived crushing pressures of 50 bars. The average atmospheric pressure on Earth's surface is 1 bar.

"We were able to show that, under putative Enceladus conditions, biological methane production occurs in the lab...Hence, some of the methane detected on Enceladus could in principle be of biological origin," Rittmann told via email.

However, not everyone is convinced.

Martin Van Kranendonk, head of the Australian Center for Astrobiology at the University of New South Wales, said the theory doesn't explain how life started on the satellite.

This is not the first time that buzz about life on the moon has been generated. Last year, a paper presented by scientists working with NASA's Cassini mission revealed that the satellite possesses a form of chemical energy that can sustain life.