A Study Claims The Possibility Of Finding “Alien Life” On Saturn’s Icy Moon
A new study shows that life can be found on one of Saturn's moons without a spacecraft landing on it.
Scientists say evidence of life on the icy moon Enceladus could be detected by a robotic spacecraft taking samples from plumes spouting liquid.
Scientists have long speculated that strange bacteria may live on Enceladus, one of the planet's 83 moons, but they had no definitive answers.
A new study suggests that the moon could be home to life because it produces methane. And when it was first surveyed by NASA in 1980, it looked like a snow globe in the sky.
A second NASA mission between 2005 and 2017 found that a thick layer of ice conceals a vast, warm ocean of salty water that releases methane, a gas that usually comes from microbes on Earth.
The methane was discovered when the mission's Cassini spacecraft flew through giant plumes of water that spewed from the surface of Enceladus.
As the young moon orbits the ringed gas giant, it is being squeezed and pulled by Saturn's massive gravitational field, which heats its interior due to friction.
As a result, amazing jets of water shoot out from fissures on Enceladus' icy surface into space.
And last year, scientists from the University of Arizona in the US and the Paris University of Sciences and Letters in France concluded that if life appears on Enceladus, this could explain why it belches methane.
While the number of bacteria in its vicinity would be small, all scientists would need to detect them would be a visit from a robotic spacecraft.
Professor Regis Ferrier, senior author of the study, explained: “It is clear that sending a robot to crawl through cracks in the ice and sink deep into the ocean floor will not be easy. More realistic missions have been designed that would use upgraded instruments to sample plumes as Cassini did, or even land on the moon.
By simulating data that more prepared and advanced orbital spacecraft could collect from plumes alone, our team has now shown that this approach would be sufficient to determine whether or not there is life within Enceladus' ocean without having to probe the depths of this moon."
Enceladus is located 800 million miles from Earth, and completes its orbit around Saturn every 33 hours.
It stands out because its surface looks like a frozen pond glistening in the sun, and it reflects light like nothing else in the solar system.
And along the moon's south pole, at least 100 giant water columns are blasting through fissures in the icy landscape, like lava from a violent volcano.
Researchers believe that water vapor and ice particles emitted from these geysers form one of Saturn's famous rings.
The excess methane being flushed into the plumes is similar to hydrothermal vents, which are found under the sea where two tectonic plates meet each other.
When they meet, hot magma beneath the seafloor heats ocean water in the porous bedrock, creating a "hydrothermal vent" that releases scorching hot, mineral-rich seawater.
Undersea microorganisms do not have access to sunlight, so they need energy from chemicals released by the "hydrothermal vent" to survive.
Professor Ferrier explained: “On our planet, hydrothermal vents teem with life, great and small, despite the darkness and the insane pressure. The simplest organisms are microbes called methanogens, which provide themselves with energy even in the absence of sunlight.
Methanogens convert dihydrogen and carbon dioxide for energy and release methane as a by-product.
The scientists' calculations were based on the theory that Enceladus contains methanogens that live in hydrothermal vents similar to those on Earth, as well as the possible exit of its cells and other organic molecules through plumes.
The team says that any regions of Enceladus that harbor life would fuel the plumes with enough cells or organic matter for instruments aboard a future spaceship to pick them up.
The team revealed that a future mission to the moon may struggle to find direct evidence of life, but the presence or absence of certain organic molecules, such as certain amino acids, would serve as indirect evidence for or against an environment full of life.
Dr Afholder added: “Definitive evidence of the existence of living cells caught in an alien world may remain elusive for generations. Until then, the fact that we can't rule out life on Enceladus is probably the best we can do.”
Scientists now want to return to Enceladus, and one mission is proposing to land there in the 1950s to collect "exhaustive" data on the subject.
The results have been published in The Planetary Science Journal.
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