Are Enceladus ‘eyeless creatures’? Why we need to explore the dark ocean of Saturn’s ‘snowball’ moon

Finding life elsewhere in the Solar System and beyond is about finding microbial life. In fact, microorganisms and “extremophiles” can exist in real environments and have ruled the Earth for much of history.

I wonder if we can find them on Saturn’s moon Enceladus?

In Saturn’s sixth largest moon, this frozen, bright moon contains everything that astrobiologists believe is essential for life as we know it to be – water, organic fertilizers and energy.

Beneath its ice shell marked by a pock, cratered and rippled, Enceladus has an ocean and many of the ingredients to support an Earth-like life. Some even argue that the dark underground ocean could be home to “eyeless creatures” that rely solely on sound.

Does Enceladus offer one of the best opportunities to discover life outside the Earth?

Here’s all you need to know about Enceladus’ Satball moon “snowball”:

Where is Enceladus?

About 870 million miles / 1,400 million kilometers from the Sun.

Enceladus is Saturn’s frozen moon – one of its 82 moons and the sixth largest to hide a liquid ocean inside. It is 310 miles / 500 km in diameter.

Something strange is happening at Enceladus. Geysers spray some of its ocean into space – a potential source for Saturn’s E-ring – which NASA’s spacecraft has confirmed contains some of the ingredients that would support life.

However, life requires energy – and Enceladus is also geologically active. Its rocky heart gives energy to that ocean largely due to Saturn’s weight bearing.

Warm and salty, the Enceladean ocean is inspired by astrobiologists.

How could Enceladus give life?

Enceladus contains water, organisms and energy sources – the three ingredients for living organisms. Cassini, now dead at NASA, found traces of salt and sand, indicating that the ocean was in contact with the rocky heart of the moon, as well as formaldehyde and acetylene.

Then in 2017, Cassini discovered molecular hydrogen as it flew through plumes from the Enceladean ocean that jumps into space through cracks in its ice shell near the moon’s south pole. Mature microbes that surround hydrothermal fins on the Earth’s ocean floor feed on hydrogen and carbon dioxide. Enceladus contains carbon, hydrogen, nitrogen and oxygen.

Could there be hydrothermal fins on the Seabed Enceladus? Similarly, Enceladus has chemistry that may support simple microbial life.

What does the ocean look like?

It is a very dark ocean of water. It covers the entire moon, but is surrounded by an ice cap about 13 miles / 20 kilometers thick, although the poles have half that. The ocean is about 25 miles / 40 kilometers deep – according to NASA’s Cassini probe – which is much deeper than Earth’s ocean. “The difference in pressure and temperature between the ocean floor of Enceladus and the ice cap above must be staggering,” wrote astrobiologist Dr. Arik Kershenbaum ann The Zoologist’s Guide to the Galaxy. “It is very likely that organisms cover that whole area. ”

A new paper published this month claims that ocean salinity is essential for the speed of water from the rock bed and the proximity of the ice cap mixture. He suggests that the mixture will either take hundreds of years, or the Enceladean ocean is much saltier than previously thought.

How might an underground ocean support life?

An underground ocean does not receive sunlight, so how could it support life? Life does not need light, it needs energy. “There is a strength of energy, partly from the decay of radioactive elements in the lunar core, but also from the freezing of the tide – the great force of Saturn’s gravity pulling the rock and water back and forth,” wrote Kershenbaum.

He believes that any life on Enceladus is likely to be in three places:

• the ocean floor
• the high ocean where it meets the ice cap
• swimming through the ocean

What would life be like in an Enceladean underground ocean?

He explains that the Enceladean ocean ecosystem is like the ocean floor on Earth just upside down – similar to the simple life found at the bottom of icebergs.

In such a situation there appear to be no creatures where the ocean meets the ice, suggests Kershenbaum, perhaps digging up in the ice to protect it. “In a dark, subterranean world, perhaps like the underground oceans of Enceladus, sight can be completely absent, and invisible creatures could develop very capable and rich communication using sound. alone, ”wrote Kershenbaum.

Could Enceladus be surprised?

A recently published paper suggests that a mixed “metabolic record” could support a potentially diverse microbial community. Using data from NASA’s Cassini spacecraft, scientists at the Southwest Research Institute (SwRI) modeled chemical processes in the underground ocean and found that oxidants in addition to carbon dioxide – if they are present – being food for microbes.

“Now that we have identified food sources for microbes, the next question is to ask‘ what kind of complex organs come out of the ocean? ‘ ”SwRI Program Director, Dr. Hunter Waite, coauthor of the new paper, said. “This new paper is another step in understanding how a small moon can sustain life in ways that are going beyond our expectations.”

Are there any missions planned to study Enceladus?

No, but there have been a couple of recommendations in recent years, including the Enceladus Life Finder (ELF) and the Enceladus Life Signatures and Habitability (ELSAH).

“A future spacecraft could fly through the Enceladus mast to test this paper’s prediction of the amount of oxidized compounds in the ocean,” said Dr Christopherm Glein, SwRI Research Senior . “We have to be careful, but I’m delighted to be wondering if there could be weird lifestyles that take advantage of those energy sources that seem to be fundamental to Enceladus’ work.”

Could this frigid moon “just” 870 million miles away be our best chance to find extraterrestrial life in the Solar System?

Wishing you clear skies and wide eyes.