Any Biomass On Saturn’s ‘Snowball Moon’ Enceladus Could Be No Bigger Than A Whale In Total, Say Scientists
Is there some kind of alien life on Saturn’s icy moon Enceladus? If there is then an orbital space probe being planned now by NASA could find it, according to a new study.
However, it also suggests that the total biomass that the moon’s underground ocean could support may be less than that of a whale.
Finding life on Enceladus would change everything.
If there is life on this world 800 million miles from Earth then it’s likely microbial (and probably not weird eyeless creatures). However, even that would change how planetary scientists and astrobiologists see the solar system, the galaxy and the universe beyond.
This Enceladus Orbilander mission—which could launch in 2038 to arrive in 2050—would orbit and land on Saturn’s tiny active moon to investigate the 100+ plumes at the moon’s south pole that are spilling into space through cracks in the icy shell. These plumes were first observed by NASA’s Cassini spacecraft, which orbited Saturn from 1997 through 2017.
Underneath its icy crust Enceladus is thought to have a warm saltwater ocean that might support microbial life in its dark depths.
In a paper published in The Planetary Science Journal researchers map out how a hypothetical space mission that could prove it there’s life—or not—in that ocean.
It’s not proposing that a robot be sent to the surface of Enceladus to enter the crevices in the ice that appear to be burping-out methane. That would be very tricky.
“By simulating the data that a more prepared and advanced orbiting spacecraft would gather from just the plumes alone, our team has now shown that this approach would be enough to confidently determine whether or not there is life within Enceladus’ ocean without actually having to probe the depths of the moon,” said Régis Ferrière, senior author of the new paper and associate professor in the UArizona Department of Ecology and Evolutionary Biology.
“This is a thrilling perspective.”
It certainly is. The water vapor and ice particles ejected by the geysers on Enceladus contain gases and other particles from deep inside the ocean. Cassini detected methane, which suggests ecosystems—possibly around hydrothermal vents.
“On our planet, hydrothermal vents teem with life, big and small, in spite of darkness and insane pressure,” said Ferrière. “The simplest living creatures are microbes called methanogens that power themselves even in the absence of sunlight.”
We’re not talking about a great deal of biomass. In fact, it’s doubtful that Enceladus could host much at all.
“We were surprised to find that the hypothetical abundance of cells would only amount to the biomass of one single whale in Enceladus’ global ocean,” said Antonin Affholder, the paper’s first author and a postdoctoral research associate at the University of Arizona, who was at L’Université PSL (Paris Sciences & Lettres) when doing this research.
“Enceladus’ biosphere may be very sparse,” he said. “And yet our models indicate that it would be productive enough to feed the plumes with just enough organic molecules or cells to be picked up by instruments onboard a future spacecraft.”
Although it seems an orbiter of some kind could identify life at Enceladus, there’s a pessimism from the researchers about whether it actually would.
If Enceladus Orbilander is to detect signs of life in the plumes it would need to fly through them multiple times, say the researchers, who warn that the amino acids it could detect would only be indirect evidence for life.
“The definitive evidence of living cells caught on an alien world may remain elusive for generations,” said Affholder. “Until then, the fact that we can’t rule out life’s existence on Enceladus is probably the best we can do.”
Wishing you clear skies and wide eyes.