Could There Be Life on a Moon of Saturn's?

Aliens. Are they real or are they just a figment of our imagination? Have they been spotted before, is the government hiding them, do they live on Mars underground in their own little society? These are questions that you all might have had. However, scientists are starting to connect methane to extraterrestrial life. That is right, the same methane that is found in cow farts. But where is this happening and what could it mean?

Enceladus

In 1997, Cassini was launched to study the planet Saturn and its system. This includes its rings and satellite. Cassini also included a tiny lander developed by the ESA called the Huygens lander, whose goal was to land on Saturn’s second-largest moon: Titan. By 2005, NASA’s Cassini orbiter was making its way past Saturn. While doing this, Cassini discovered geysers blasting particles of water ice into space. After some investigation, the Cassini orbiter found out that these particles were coming from “tiger stripe” fractures near the South Pole of Enceladus. Some of the material that was coming out of the fracture formed a plume that eventually became a part of Saturn’s E Ring (the second-outermost ring). Because of this, many scientists are starting to hypothesize that there is a huge ocean of liquid water under Enceladus’s icy surface.

Cassini Orbiter Around Saturn

Water ice wasn’t the only thing in the plume. During close flybys by Cassini to Enceladus, Cassini spotted many organic compounds. Some were dihydrogen (H2) and methane (CH4). The discovery of these two compounds intrigued many astrobiologists. They theorized that H2 is most likely being created by an interaction between rocks and hot water on Enceladus’s seafloor, similar to hydrothermal vents on the Earth’s ocean floor, which is where many scientists have theorized was where life on Earth originated from.

Cycle for Methanogenesis

H2 also provides energy from microbes on Earth that produce methane from carbon dioxide, a process called methanogenesis. Astrobiologists believe that this process may be happening on Enceladus, which explains the presence of methane on Enceladus. A team of astrobiologists led by   Régis Ferrière, an associate professor in the University of Arizona's Department of Ecology and Evolutionary Biology, then constructed models based on the H2 production and wanted to assess the probability that methane on Enceladus was generated biologically. The team also created simulations to see whether the H2 production could sustain microbial life, how the population rate would change with a change inH2 production, and how methane escaped into the plume.

The team concluded that abiotic hydrothermal-vent chemistry doesn’t explain the methane presence on Enceladus, but the methanogenic microbes do. Though, this doesn’t mean that there has to be life on Enceladus and that there. For example, it is possible that Enceladus may have reserves of methane created by other processes that are not present on Earth. Another theory is primordial decay, which says there was once organic life on Enceladus, but now there is no life, hence the presence of methane. Finally, one theory also says that organic compounds were brought to Enceladus by comets. Nonetheless, there is still a chance that there is life on Enceladus. Who knows, maybe the closest extraterrestrial life isn’t on Mars but on Enceladus.

Hydrothermal Vent Theory on Enceladus

Sources:

“Cassini–Huygens.” Wikipedia, Wikimedia Foundation, 8 July 2021, en.wikipedia.org/wiki/Cassini%E2%80%93Huygens. 

“Enceladus.” Wikipedia, Wikimedia Foundation, 7 July 2021, en.wikipedia.org/wiki/Enceladus. 

“Methanogenesis.” Wikipedia, Wikimedia Foundation, 3 July 2021, en.wikipedia.org/wiki/Methanogenesis. 

Wall, Mike. “Methane in Plume of Saturn's Moon Enceladus Could Be Sign of Alien Life, Study Suggests.” Space.com, Space, 7 July 2021, www.space.com/methane-plume-enceladus-possible-sign-alien-life.