Cassini finds molecular hydrogen in the Enceladus plume: Evidence for hydrothermal processes
> Saturn's moon Enceladus has a subsurface ocean covered by a layer of ice. Some liquid escapes into space through cracks in the ice, which is the source of one of Saturn's rings. In October 2015, the Cassini spacecraft flew directly through the plume of escaping material and sampled its chemical composition. Waite et al. found that the plume contains molecular hydrogen, H2, a sign that the water in Enceladus' ocean is reacting with rocks through hydrothermal processes (see the Perspective by Seewald). This drives the ocean out of chemical equilibrium, in a similar way to water around Earth's hydrothermal vents, potentially providing a source of chemical energy.
A way to remember it is that Enceladus is the snowball with the blue "tiger stripes" on the south pole (grooved vents through which shoot streams of ice crystals [driven by tidal heating along its orbit around Saturn]).
If life is there, completely disconnected from earth life, it would be dramatic. That would mean that our solar system, has life on at least two, out of nine planets. That would seem to indicate that life is a fairly common things on planets. It would allow to adjust the drake equation, to easily predict millions of planets with life. And that would mean a high probability of many advanced, intelligent civilizations on the universe.
Based on the developments in exo-planet research along with discoveries like this over the past couple of years, I would conjecture that life is ridiculously common. But by life, I mean microbial life. I would imagine that multi-cellular life is much rarer, and life capable of reaching human-level intelligence and beyond is probably absurdly rare, on the level of something like one species per galaxy. It's all worthless conjecture, of course, but the point is I wouldn't be surprised if microbial life is very, very common.
> If life is there, completely disconnected from earth life,
IIRC (I can't find the reference now), the "dinosaur killer" asteroid would put rocks from Earth into space. With sufficient velocity that they could reach nearby solar systems within 100M years.
So from a strictly physical point of view, I would argue that the odds of Earth "infecting" Europa with life in the past 3 billion years are pretty much 100%.
It wouldn't really be surprising. Prokaryotic life appeared on Earth very quickly after the Earth cooled down. But it took a very long time after that for Eukaryotic cells to develop. Just going from Earth history I'd expect lots of planets with bacterial mats but very few with complex or multi-cellular life.
It would be, but let's not get ahead of ourselves: all they've done is found evidence that it would be habitable by extremophile organisms. There's no evidence there actually are any.
Well, deep sea, thermal vent life is predominantly blind on earth at least. One may postulate this form of life is much less likely to form technological civilizations thus moderating such. Thoughts?
how would determine that it's completely disconnected? not asking snarkily. seems like you could push the goalposts back to say that whatever allows for life on earth is true of earth + our neighborhood/solar system, but not necessarily elsewhere, sort of like how the definition of AI keeps expanding.
What's the posterior distribution over numbers of life forms in the universe under some conservative prior and after finding that this moon has life, too? (Plus assuming that these events are independent, which they are probably not.)
I always had this question - Can life exist outside our perception of biological life?
Intelligent life might be an anomaly, and rare in the universe - but is it possible that life exists outside our perception of biology? Afterall everything is just rules and actions that lead to predictable reactions (unless quantum physics says something else)
I look at artificial life - that exists in virtual environments. It looks like life - but we know it isn't for real. It cannot replicate/grow outside its environment. But that argument could be used to for all non-human life on Earth, if humans never existed.
Even stuff like mars rover could be engineered to mine, manufacture and duplicate - eventually creating a colony of rovers that populate the planet and consume the planet's resources. Well, that might look like semi-intelligent life - but we know it isn't - or is it life?
There are many very good reasons to expect a lot of the life in the universe to resemble ours at least in its chemistry. That's because, perhaps aside from dark matter, we know what elements the observable universe is made of and we know the chemistry and physics of those elements pretty well. Of these elements, we know that carbon chemistry is the richest and most complex of any of them by several orders of magnitude. Also the temperature range in which that chemistry reaches its peak complexity is the temperature range of Earth.
This isn't anthropomorphism and it's hard to see any bias in play. This is simple extrapolation from the physics and chemistry of the universe we can observe within the some 14bn light years range visible to us.
Of course there may be many different possible realisations if that chemistry. There may be many possible alternative structures other than DNA for things like heredity and alternative building blocks to proteins and such, but if there are such alternatives they are orders of magnitude more likely to be based on carbon chemistry than anything else.
If you rank the elements in the observable universe in order if prevalence, other than Helium you get the same answer as if you rank the elements in order if prevalence in our bodies. We are made of the most common materials anywhere in the universe. In terms of composition there is nothing special about us at all.
Finally, it's hard to see how natural selection or evolution are special to the conditions on Earth. There no real reason to believe that these would not apply to any other form of life.
So it's absolutely important that we try to be objective and keep an open mind. There may be much about the universe we don't know. I've already mentioned dark matter. But from what we do know, there are good reasons to look for life in worlds somewhat like our own.
If you enjoy pondering this question you should definitely check out the works of Stanislaw Lem. One of the main themes of his work is that alien life would be fundamentally different from life as we know it and that human consciousness, bound by the concepts that we use to understand our own world, would be unable to comprehend it. His novels contain a lot of imaginative examples of that kind of alien life, the most famous perhaps being the planet in Solaris.
I recommend you read 'The Vital Question' it touches on this topic.
The short answer is that if you define 'life' to be engines which convert energy into additional engines then yes there is life outside our perception of biological life, but at that point 'life' is just 'chemistry'. And 'engine' is defined to be a self-contained collection of elements that you can feed energy into.[1]
[1] I know not as crisp as it should be, but read the book its really interesting. Especially when you get to the point talking about geo-chemistry and bio-chemistry being the same thing pretty much.
> Even stuff like mars rover could be engineered to mine, manufacture and duplicate - eventually creating a colony of rovers that populate the planet and consume the planet's resources.
That's one of my favorite thought experiments in approaching the definition of life:
Suppose we build some robots with AI, and send them into space, and they land on some planet.
Those robots can mine raw materials and build other robots like themselves.
They're able to learn and teach each other, and improve their design and invent new things on their own.
Fast forward a few hundred years. That planet now hosts a civilization of robots, with their own culture, planning their own excursions into space.
To an external observer searching for Life™ and Intelligence™ in the cosmos, what would make our robot civilization fail to be qualified as such?
The universe being so vast and so diverse, most life forms will probably escape our comprehension: completely different chemistry, environments (pressures, temperatures), time scales, state of matter (plasma based life forms?), or even energy based ones.
We are not even looking for such different life forms, since we have already concluded that:
- life must be water based
- life must be carbon based
- life must be based on dna (or simillar)
Which leads (given our limited knowledge of the chemistry of these substances) to the conclussion that life must be extremely similar to Earth's.
Not a huge surprise. Most likely our kind of environment is an unusual place for life, it might be much more normal for life outside the frost line to run on geothermal energy (where there are 10 or so bodies with liquid water) as opposed to the one small rock that didn't get all the water boiled away by the sun.
I feel the same way about the Voyagers... Launched when I was in early primary school. Incredible to think that it will still be out there long after I am not around.
I've always been fascinated by that project, and follow all news on it that I can, and was blown away recently to actually have a Twitter conversation with someone who did one of the voices on the 'Golden Record'.
This makes Tethys and Rhea very tempting places for permanent occupation - they have abundant ice on the surface (easy to dig if you have a power source) and the delta-v's between them and the surface of Enceladus are between 1000 m/s and 3000 m/s, something chemical rockets can do easily.
Just in the last day or so, reporting on some experiment supposedly demonstrating that asteroid impacts on Earth are/were capable of creating the amino acid precursors to RNA.
Yeah, really, this demonstrates nothing, on its own. But, interesting to think about.
Is there tectonics on that moon ? Isn't it too small for that ? The same goes for Europa... Is there real tectonics there ?
If there is no tectonics in place and you have a "closed" big bucket of water constantly filled up with chemicals from hydrothermal vents during billions of years, wouldn't the water become completely soaked and kind of slimy ? Not the best place for life, even for extremophiles...
So here's an orthogonal question. In a field like space navigation, where your findings come back after an expedition planned 5-10+ years ago how do you be "agile"?
What is the go to project management style? Can we learn from these disciplines for alternative practices to building software?
For those interested in this topic, I recommend "Astrobiology: A Very Short Introduction" by David Catling. Catling details nine celestial bodies in the solar system that could potentially harbor life, and discusses Enceladus is some detail.
Well, Enceladus has an energy source that could perhaps be a source of energy for some kind of living organism. "Able" kind of says that all you need for life is some kind of available energy, which... let's just call that "unproven".
[+] [-] _rpd|9 years ago|reply
Cassini finds molecular hydrogen in the Enceladus plume: Evidence for hydrothermal processes
> Saturn's moon Enceladus has a subsurface ocean covered by a layer of ice. Some liquid escapes into space through cracks in the ice, which is the source of one of Saturn's rings. In October 2015, the Cassini spacecraft flew directly through the plume of escaping material and sampled its chemical composition. Waite et al. found that the plume contains molecular hydrogen, H2, a sign that the water in Enceladus' ocean is reacting with rocks through hydrothermal processes (see the Perspective by Seewald). This drives the ocean out of chemical equilibrium, in a similar way to water around Earth's hydrothermal vents, potentially providing a source of chemical energy.
http://science.sciencemag.org/content/356/6334/155
[+] [-] shrimp_emoji|9 years ago|reply
[+] [-] nzonbi|9 years ago|reply
[+] [-] charles-salvia|9 years ago|reply
[+] [-] adekok|9 years ago|reply
IIRC (I can't find the reference now), the "dinosaur killer" asteroid would put rocks from Earth into space. With sufficient velocity that they could reach nearby solar systems within 100M years.
So from a strictly physical point of view, I would argue that the odds of Earth "infecting" Europa with life in the past 3 billion years are pretty much 100%.
[+] [-] Symmetry|9 years ago|reply
[+] [-] moomin|9 years ago|reply
[+] [-] marktangotango|9 years ago|reply
[+] [-] disantlor|9 years ago|reply
[+] [-] tmalsburg2|9 years ago|reply
[+] [-] jordache|9 years ago|reply
I've already come to the conclusion that there is/was some sort of life within our solar system.
Intelligent life is much more rare. If there is some evidence of that in our solar system, I would be floored
[+] [-] IndianAstronaut|9 years ago|reply
[+] [-] ufo|9 years ago|reply
[+] [-] ziikutv|9 years ago|reply
[+] [-] otempomores|9 years ago|reply
[+] [-] otempomores|9 years ago|reply
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[+] [-] moomin|9 years ago|reply
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[+] [-] smdz|9 years ago|reply
Intelligent life might be an anomaly, and rare in the universe - but is it possible that life exists outside our perception of biology? Afterall everything is just rules and actions that lead to predictable reactions (unless quantum physics says something else)
I look at artificial life - that exists in virtual environments. It looks like life - but we know it isn't for real. It cannot replicate/grow outside its environment. But that argument could be used to for all non-human life on Earth, if humans never existed.
Even stuff like mars rover could be engineered to mine, manufacture and duplicate - eventually creating a colony of rovers that populate the planet and consume the planet's resources. Well, that might look like semi-intelligent life - but we know it isn't - or is it life?
[+] [-] simonh|9 years ago|reply
This isn't anthropomorphism and it's hard to see any bias in play. This is simple extrapolation from the physics and chemistry of the universe we can observe within the some 14bn light years range visible to us.
Of course there may be many different possible realisations if that chemistry. There may be many possible alternative structures other than DNA for things like heredity and alternative building blocks to proteins and such, but if there are such alternatives they are orders of magnitude more likely to be based on carbon chemistry than anything else.
If you rank the elements in the observable universe in order if prevalence, other than Helium you get the same answer as if you rank the elements in order if prevalence in our bodies. We are made of the most common materials anywhere in the universe. In terms of composition there is nothing special about us at all.
Finally, it's hard to see how natural selection or evolution are special to the conditions on Earth. There no real reason to believe that these would not apply to any other form of life.
So it's absolutely important that we try to be objective and keep an open mind. There may be much about the universe we don't know. I've already mentioned dark matter. But from what we do know, there are good reasons to look for life in worlds somewhat like our own.
[+] [-] jhedwards|9 years ago|reply
[+] [-] tcfunk|9 years ago|reply
[+] [-] Kalium|9 years ago|reply
We assume so! But we restrict our scarce looking-for-life resources to conditions where we know life can exist.
[+] [-] ChuckMcM|9 years ago|reply
The short answer is that if you define 'life' to be engines which convert energy into additional engines then yes there is life outside our perception of biological life, but at that point 'life' is just 'chemistry'. And 'engine' is defined to be a self-contained collection of elements that you can feed energy into.[1]
[1] I know not as crisp as it should be, but read the book its really interesting. Especially when you get to the point talking about geo-chemistry and bio-chemistry being the same thing pretty much.
[+] [-] hammock|9 years ago|reply
[+] [-] Razengan|9 years ago|reply
That's one of my favorite thought experiments in approaching the definition of life:
Suppose we build some robots with AI, and send them into space, and they land on some planet.
Those robots can mine raw materials and build other robots like themselves.
They're able to learn and teach each other, and improve their design and invent new things on their own.
Fast forward a few hundred years. That planet now hosts a civilization of robots, with their own culture, planning their own excursions into space.
To an external observer searching for Life™ and Intelligence™ in the cosmos, what would make our robot civilization fail to be qualified as such?
[+] [-] marmshallow|9 years ago|reply
https://news.ycombinator.com/item?id=12994455
[+] [-] Balgair|9 years ago|reply
;)
[+] [-] Stanleyc23|9 years ago|reply
[+] [-] arunix|9 years ago|reply
Meanwhile the Earth has a heart (core), blood (mantle), skin (crust) etc, it also throbs with 'life' unlike many other dead worlds out there.
Neptune is very much 'alive' compared to Uranus etc ...
[+] [-] gonvaled|9 years ago|reply
The universe being so vast and so diverse, most life forms will probably escape our comprehension: completely different chemistry, environments (pressures, temperatures), time scales, state of matter (plasma based life forms?), or even energy based ones.
We are not even looking for such different life forms, since we have already concluded that:
- life must be water based
- life must be carbon based
- life must be based on dna (or simillar)
Which leads (given our limited knowledge of the chemistry of these substances) to the conclussion that life must be extremely similar to Earth's.
I see a lack of imagination here.
[+] [-] PaulHoule|9 years ago|reply
[+] [-] aphextron|9 years ago|reply
[+] [-] cyberferret|9 years ago|reply
I've always been fascinated by that project, and follow all news on it that I can, and was blown away recently to actually have a Twitter conversation with someone who did one of the voices on the 'Golden Record'.
[+] [-] rbanffy|9 years ago|reply
[+] [-] pasbesoin|9 years ago|reply
Yeah, really, this demonstrates nothing, on its own. But, interesting to think about.
[+] [-] dave_ant|9 years ago|reply
If there is no tectonics in place and you have a "closed" big bucket of water constantly filled up with chemicals from hydrothermal vents during billions of years, wouldn't the water become completely soaked and kind of slimy ? Not the best place for life, even for extremophiles...
I also found an interesting article on the probable high acidity of Europa ocean, that would make it not suitable for harboring life : http://www.space.com/14757-europa-moon-ocean-acidic.html
I guess it could also apply to Enceladus ocean. Can someone elaborate on that ?
P.S.: English is not my native language, sorry for any grammatical incoherence :)
[+] [-] yomly|9 years ago|reply
What is the go to project management style? Can we learn from these disciplines for alternative practices to building software?
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