Saturn's ocean moon Titan may not be able to support life after all

[Admin]

Organic material on Saturn moon Titan's surface may have difficulty getting to the underground ocean. That's where it'd need to go for Titan to potentially support life.

Saturn's ocean moon Titan may not be able to support life after all : Read more

 

[rod]

Space.com stated, "And where there is liquid water, there could be life. Right? Not so fast, says Catherine Neish of Western University in Ontario, Canada. A planetary scientist, Neish led an international team that challenged the assumption Titan's ocean, and indeed the oceans of other icy moons, could be habitable. The researchers worked on the basis that, for Titan's ocean to be habitable, a large supply of organic molecules from the surface must be able to physically reach the ocean in order to facilitate prebiotic chemistry that can produce and feed life."

An important model observation. Ref - Organic Input to Titan's Subsurface Ocean Through Impact Cratering, https://www.liebertpub.com/doi/10.1089/ast.2023.0055

"Abstract Titan has an organic-rich atmosphere and surface with a subsurface liquid water ocean that may represent a habitable environment. In this work, we determined the amount of organic material that can be delivered from Titan's surface to its ocean through impact cratering. We assumed that Titan's craters produce impact melt deposits composed of liquid water that can founder in its lower-density ice crust and estimated the amount of organic molecules that could be incorporated into these melt lenses. We used known yields for HCN and Titan haze hydrolysis to determine the amount of glycine produced in the melt lenses and found a range of possible flux rates of glycine from the surface to the subsurface ocean. These ranged from 0 to 10^11 mol/Gyr for HCN hydrolysis and from 0 to 10^14 mol/Gyr for haze hydrolysis. These fluxes suggest an upper limit for biomass productivity of ∼10^3 kgC/year from a glycine fermentation metabolism. This upper limit is significantly less than recent estimates of the hypothetical biomass production supported by Enceladus's subsurface ocean. Unless biologically available compounds can be sourced from Titan's interior, or be delivered from the surface by other mechanisms, our calculations suggest that even the most organic-rich ocean world in the Solar System may not be able to support a large biosphere."

Looks like astrobiology must work harder to establish life evolved via abiogenesis and then grew and lived on icy outer moons in our solar system. So far, extending Charles Darwin warm little pond in his 1871 letter to other places in the solar system (or exoplanets), remains unconfirmed science.

 

[Walkermill12]

A ridiculous single minded study.
A lot of assumptions from one study barely peer reviewed.
I thought science was about science not generalization and opinion.
A conclusion based on this, generalizing the outer solar system as uninhabitable lacks both fact and proper analysis.
There.

 

[Walkermill12]

Organic material on Saturn moon Titan's surface may have difficulty getting to the underground ocean. That's where it'd need to go for Titan to potentially support life.

Saturn's ocean moon Titan may not be able to support life after all : Read more

There are other sources of organic compounds and relying on one source for an alien body we know nothing about simply on the basis that we think that's how it was deposited on our world is not definitive evidence supporting the idea everyone is currently circulating that there is no life in the outer solar system.
The headline simply can not be defended.
One barely peer reviewed study doesn't offer conclusive evidence that the ocean is void of life. Let alone that are of the solar system.
It's not even evidence based.

 

[jamestmallow]

A ridiculous single minded study.
A lot of assumptions from one study barely peer reviewed.
I thought science was about science not generalization and opinion.
A conclusion based on this, generalizing the outer solar system as uninhabitable lacks both fact and proper analysis.
There.

Take it easy there, buddy. I want there to be life swimming around in Titan's ocean too. This is just a study that is skeptical. At this point nobody knows.

 

[Torbjorn Larsson]

Organic material on Saturn moon Titan's surface may have difficulty getting to the underground ocean. That's where it'd need to go for Titan to potentially support life.

Saturn's ocean moon Titan may not be able to support life after all : Read more

The prior for ice-locked oceans with ice above and below, and specifically for the hypothesized alkalic Titan ocean, has never been high.

But we know that Enceladus's ocean with its rock floor has both energy and organics from the methane spewing hydrothermal vents. Cassini found that Enceladus's vents has 1 % of carbon dioxide, methane and ammonia, as well as more complex organics. https://www.smithsonianmag.com/smar...-plumes-saturns-ice-moon-enceladus-180973282/https://science.nasa.gov/missions/cassini/complex-organics-bubble-up-from-ocean-world-enceladus/.

 

[Torbjorn Larsson]

Looks like astrobiology must work harder to establish life evolved via abiogenesis and then grew and lived on icy outer moons in our solar system. So far, extending Charles Darwin warm little pond in his 1871 letter to other places in the solar system (or exoplanets), remains unconfirmed science.

It is not the task of astrobiology to establish that life evolves on Earth, it is geobiology that observes that early molten lava ocean Earth was sterile and now it isn't.

Testable phylogenies that cover the split between biology and geology exists since 2016, and they show that Darwin's "warm little pond" was not involved. Early life emerged in the deep ocean, likely while Earth was still ocean covered. Weiss, M., Sousa, F., Mrnjavac, N. et al. The physiology and habitat of the last universal common ancestor. Nat Microbiol 1, 16116 (2016). https://doi.org/10.1038/nmicrobiol.2016.116

Based on geobiology results then, we can move on to astrobiology, which task it is to establish habitability and inhabited frequency elsewhere. We know that Mars and Enceladus, and most likely Venus before it went hothouse, had the same alkaline hydrothermal vents. The martian Spirit rover died in one, and Enceladus plumes are driven by others. That means the prior for extinct and possibly extant (on Mars, subsurface; on Enceladus, under ice cover) life is confirmed to be high. Considering that the discipline is mere decades old, it is already a huge advance to move on from Earth as type case to importing a predictive theory for early evolution.

But confirmed life is obviously not at evidence since astrobiology is still looking for it. In my own opinion that is setting an impossible bar for finding personal meaning in current astrobiology.

 

[AJH]

“… one male African elephant spread across an ocean with a dozen times the volume of Earth's oceans."

That is an… oddly specific point of reference.

 

[billslugg]

And if the elephant were to mate with a whale, his kids would have their own snorkels.

 

[AJH]

And if the elephant were to mate with a whale, his kids would have their own snorkels.

Now that's a sea creature I’d be willing to ride into battle!

 

[Questioner]

If that's gone on for 4 billion years or so that's 66.136 trillion pounds of organics.
Which if my calculations are correct is 0.0027556667
(3/10ths of one percent) times as rich as Earth's oceans.
It's thin/watery, but perhaps it's enough to get something working.
And perhaps in formation Titan had some initial organics as well.

 

[AJH]

I think that the really big takeaway from this article isn’t necessarily that life is unpossible on Titan, but that life as we know it might not be possible. Did anybody really expect to find carbon-based organics flopping around in the subsurface ocean? What I think is really fascinating, though, is Titan’s methane cycle as an analogue to Earth’s water cycle, and what sorts of things could (theoretically) be produced in that kind of environment. Frankly, I think that discovering something that is entirely unlike life on Earth would be far more meaningful, scientifically and philosophically.