[HN Gopher] Saturn's moon Titan could harbor life, but only a ti...
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Saturn's moon Titan could harbor life, but only a tiny amount
Author : geox
Score : 52 points
Date : 2025-04-07 21:31 UTC (3 days ago)
(HTM) web link (news.arizona.edu)
(TXT) w3m dump (news.arizona.edu)
| nkrisc wrote:
| > "Our new study shows that this supply may only be sufficient to
| sustain a very small population of microbes weighing a total of
| only a few kilograms at most - equivalent to the mass of a small
| dog," Affholder said. "Such a tiny biosphere would average less
| than one cell per liter of water over Titan's entire vast ocean."
|
| Assuming for a moment that some life does exist in the subsurface
| ocean, I imagine it would be most likely that you would then
| expect to find very, very rare, but highly concentrated pockets
| of life?
|
| Unfortunately I couldn't read the linked study because I was
| stuck in an endless CAPTCHA loop of trying to find an image of a
| refrigerator among a varying set of only helicopters, ships, and
| avocados. I feel absurd just writing that.
| pavel_lishin wrote:
| There's only one refrigerator per liter of images in the
| CAPTCHA.
| marcosdumay wrote:
| And unfortunately, the GP's monitor is 2D only, so the total
| amount of refrigerators was zero.
| 38 wrote:
| > Unfortunately I couldn't read the linked study because I was
| stuck in an endless CAPTCHA loop of trying to find an image of
| a refrigerator among a varying set of only helicopters, ships,
| and avocados
|
| I got through on the first try, and I block third party
| JavaScript with a whitelist
| nkrisc wrote:
| The one I got told to me find refrigerators and then never
| showed me a refrigerator. I clicked "skip" many times and it
| just kept going until I gave up.
| misnome wrote:
| I'm sorry to suggest this, but have you considered that you
| might be a robot?
| kridsdale3 wrote:
| These days it's hard to tell.
| throwaway777452 wrote:
| You probably misread it and it said to pick objects that go
| inside the refrigerator, so you were supposed to pick the
| avocados.
| seanhunter wrote:
| You don't put avocados in a refrigerator in many
| countries of the world. IF you do, they will just go
| brown without ever becoming ripe.
| AStonesThrow wrote:
| I am reminded of the intersection between _Indiana Jones
| and the Crystal Skull_ , and xkcd 2228:
|
| https://tvtropes.org/pmwiki/pmwiki.php/Main/BombproofApplia
| n...
|
| https://m.xkcd.com/2228/
|
| Hey, wouldn't a refrigerator be an ideal space vessel for
| humans to explore Titan?
| Qem wrote:
| Are bolide impact events the only possible mechanism for
| communication between ice crust and subsurface ocean? Is there no
| analogue to tectonism on Titan ice crust, to subduct nutrient
| rich ice?
| indoordin0saur wrote:
| Yeah the study seems to make 4 assumptions:
|
| 1.) The life's only metabolic source of energy is glycine
|
| 2.) The life is analogous to glycine metabolizing organisms on
| Earth
|
| 3.) The only source of glycine getting deep into the ocean is
| through these rare impact events
|
| 4.) The life can only survive in the deep subsurface ocean
| datameta wrote:
| Speaking of ocean, water is mentioned several times in
| discussing Titan but the hydrologic cycle analogue consists
| of various hydrocarbons.
|
| But to the fourth point, I wonder to what extent radiation is
| a factor in mutation of biological material. It turns out
| Titan has a rather low surface irradiation coefficient due to
| being rather distant from Saturn's radiation belt, a weak
| induced magnetosphere (rare for moons!), and the ions are
| mostly water-based coming from Enceladus while Jupiter's
| radiation belts are largely sulphur ions coming from Io.
| indoordin0saur wrote:
| The hydrocarbon oceans are on the surface, but there are
| liquid water oceans beneath the surface.
| zoklet-enjoyer wrote:
| As a treat
| dfedbeef wrote:
| A tiny wafer thin layer of life
| bpodgursky wrote:
| > The researchers specifically focused on one organic molecule,
| glycine, the simplest of all known amino acids.
|
| This is such a goofy assumption. That any life on Titan would use
| the exact same amino acids as earth-based life. If you have no
| clue whether something is possible, sometimes it's better to
| predict nothing at all.
| Tagbert wrote:
| It's not goofy. We find these amino acids in meteorites and it
| is clear that they are widespread in space. Glycine being the
| simplest is probably the most common and most likely to be
| incorporated by life. It is a good proxy for an estimate.
| bilekas wrote:
| > This is such a goofy assumption. That any life on Titan would
| use the exact same amino acids as earth-based life.
|
| I might be wrong, but I think they use this assumption because
| they KNOW life has already formed this way, it would be goofy
| to assume methods that we haven't witnessed right ?
| ceejayoz wrote:
| That's still a bit goofy; it's essentially the same thing as
| the https://en.wikipedia.org/wiki/Cargo_cult phenomenon.
| bilekas wrote:
| Maybe I missed the mark here but is it not similar to
| saying "it seems goofy to look on planets with water just
| because that's what life required on earth"?
|
| I'm not in any way educated on these things but are these
| not basic building blocks kind of things?
| ceejayoz wrote:
| We know the basic building blocks for Earth life.
|
| We currently have zero evidence for any life off the
| planet, water/carbon-based or otherwise. It would likely
| be a mistake to assume that we're the only possible
| setup. Maybe life spreads primarily and very slowly in
| Oort clouds, and we're a bit of an abberation.
|
| Even here on Earth, we've been surprised to find life in
| boiling water and miles underground.
| behringer wrote:
| And if they found loads of this amino acid, would you say the
| same thing? Science isn't about getting the best answers, it's
| about getting accurate answers. Now that we know all about this
| amino acid in relation to titan, we can follow the rabbit hole
| to find sources of it on Titan or we can decide to look for
| alternatives.
| AStonesThrow wrote:
| The search for water in outer space, and other life-sustaining
| elements, has ulterior motives.
|
| I believe that the search for alien life is subordinate to the
| search for things that will sustain human life and/or industry,
| as we expand further outwards.
|
| Most scientists and engineers don't actually expect to
| encounter significant alien life in our solar system, and it's
| merely a meme they use to tease middle-schoolers, Senators,
| CEOs, and naive newspaper readers. Searching and discovering
| _life forms_ would be really really fraught with terror and
| doom, if we indeed expected to find it when we looked.
|
| Any natural resource that exists on a moon of Jupiter, or of
| Saturn or in the Asteroid Belt, and if we can exploit it and
| extract it and turn it into something useful, for example
| refueling, or life support, or repairing existing vehicles en
| route, or simply dragging raw materials back down the gravity
| well to Earth, then that is a natural resource we'll want to
| investigate as we expand. Dyson spheres won't be built in a
| day, but we'll need a good start on the resource extractions
| real soon now.
|
| This is the quiet part they won't say out loud, because it's
| much more exciting and non-threatening to say we're looking for
| alien life forms rather than sustaining our own self-interest.
| But it's all about self-interest when it comes to humans.
| causality0 wrote:
| God what a fucking leap from the actual results of the study to
| that article title. The only thing the study indicated with even
| the barest hint of significance is that there is probably only a
| very limited amount of glycine being transported from the surface
| to the interior ocean. That's it.
| NoTeslaThrow wrote:
| Imagine what humanity could be capable of if we had the grace
| to ignore the title.
| mytailorisrich wrote:
| I think the most plausible takeaway is that, assuming this study
| is "correct", if a process would only allow a few kg of life at
| planetary scale then that process is not what life would rely on
| in that environment.
| julik wrote:
| I hope there will be sirens...
| https://en.wikipedia.org/wiki/The_Sirens_of_Titan
| SamBam wrote:
| I'm interested that their conclusion -- that Saturn could only
| support tiny life forms such as bacteria -- is not dependent in
| any way on the distance from Titan to the Sun.
|
| Am I wrong in thinking that any life must require a steady input
| of energy, and that this must come from either solar energy or
| geothermal energy? Quick Googling says that Titan's core isn't
| known for sure, but probably isn't very hot.
|
| If Titan's life were dependent of solar energy, wouldn't it's
| distance from the Sun imply very little energy to go around, and
| so very unlikely to have large organisms?
| delecti wrote:
| The gas giants' moons are heated quite a bit by tidal friction.
| They're warmer than would be expected just based on their
| distance from the sun.
| adrian_b wrote:
| Solar energy can be captured only by living beings that have
| reached a relatively high complexity after a long evolution.
|
| In places with so little solar energy, living beings might
| never develop means for capturing it.
|
| For the appearance of life, a source of internal heat for the
| planet or satellite is a necessary condition.
|
| As another poster has mentioned, in the big satellites of the
| giant planets such a source of internal heat exists, because of
| the tidal forces which cause internal friction.
|
| For the internal heat to be able to provide energy for life
| forms, there must exist some kind of volcanism that cycles
| matter between the interior and the exterior of the satellite
| or planet, so that substances that were in chemical equilibrium
| at higher temperatures are brought to lower temperatures, where
| they are no longer in chemical equilibrium, which can provide
| the energy for the synthesis of complex organic molecules.
|
| (On Earth, the principal source of energy for the bacteria that
| do not depend on solar energy has its origin in the iron(II)
| ions from the mantle and lower crust of the Earth, which are
| brought by volcanism at the surface, where they are no longer
| in chemical equilibrium with water, so they are oxidized by
| water to Fe(III) ions, i.e. rust, liberating elemental hydrogen
| from the water, which can be consumed by bacteria and combined
| with carbon dioxide into organic substances, without needing
| any other source of energy. When rocks are recycled by
| subduction into the mantle, because of the high temperatures
| the iron ions are reduced again to Fe(II) ions, completing the
| cycle by consuming a certain amount of internal heat.)
| blacksmith_tb wrote:
| Hmm, didn't cyanobacteria / blue-green algae evolve early in
| Earth's history? I would agree that chemosynthesis seems like
| a better bet so far away from the sun, though).
| Symmetry wrote:
| Relatively early but there was at least 500 million and
| perhaps over a billion years separating the first life and
| the first photosynthesis. At least as much time as between
| us and the Cambrian Explosion.
|
| https://en.wikipedia.org/wiki/Timeline_of_the_evolutionary_
| h...
| SamBam wrote:
| Sure, but that's basically my point, or at least the point I
| thought I was making. Chemosynthesis can provide enough
| energy for bacteria, but to have anything much larger than
| bacteria you'd need a bigger source of energy, such as high
| solar radiation, right?
| Symmetry wrote:
| Life on Earth was dependent on chemosythesis for the better
| part of a billion years before photosynthesis was developed.
| Photosynthesis is really very complex so I think we can rule
| that out as an initial form of life.
|
| Hydrothermal vents are a great source of chemical energy in the
| form of hydrogen, hydrogen sulfide, or other chemicals that can
| be reacted for energy where the come out into the sea. But you
| could imagine other sorts of chemical energy driven by other
| geologic or atmospheric processes that life might bootstrap
| from.
| bagels wrote:
| How do they know that there wasn't already abundant amino acids
| in the ocean before accounting for current transfer?
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