Hycean exoplanet with tantalising makeup

Venusian Broon

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Always be a bit cautious with initial results and to try and see if other, perhaps more disappointing, hypotheses are better (i.,e. I'm looking at you, Tabby's star) but K2-18b could have a liquid water surface and may exhibit a couple of very interesting atmospheric gases concentrations that are hard to explain, namely carbon dioxide and dimethyl sulphide.

Let's not get carried away thinking that this super-Earth might have alien life on it, but it's nice to ponder!

 

Brian G Turner

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Let's not get carried away thinking that this super-Earth might have alien life on it, but it's nice to ponder!
Definitely not something to get excited about - sounds more like like an early Earth, in the first couple of billion years, before complex life.
 

Venusian Broon

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Definitely not something to get excited about - sounds more like like an early Earth, in the first couple of billion years, before complex life.
Finding any life, even if simple bacteria-like, that is not connected at all to life on Earth is very exciting. At least for me - it's a big question that I would love to be answered.

But such a discovery, although it will not overturn civilisation, will re-adjust and expand our mental outlook of the universe and our position in it, in ways that we cannot imagine now.

I can remember pre-1987 when we had never detected a single exo-planet. We could not, hands on our scientific hearts, really be sure that exo-planets actually existed. Sure, most or many of us thought other stars must have planets orbiting them, but all we had was a sample of one single system. Now that we have discovered so many planetary systems, of such varied properties and ranges, it may seem a mundane revelation to those brought up with this knowledge. But it was really, quite a profound change in our view of the universe. Believe me I was there before and after ;).

Finding (perhaps) that Earth is not as special as we feel it is with regards to life, would be an even bigger change.
 

Brian G Turner

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Yes, certainly good - I'm more excited at the prospect of the different planetary profiles we'll get to see with JWST. :)

As for other planets and life elsewhere - frankly I see this as simple question as to whether someone believes life was created directly by God solely on Earth, or whether the development of life is a natural part of the universe and therefore will be found across it.

Frankly I find the suggestion from any rationalist that we can't say there's life elsewhere because we haven't seen it yet quite astonishing, because that implies life is not a natural phenomenon, and additionally that the laws of physics don't work on other planets! Additionally, there's plenty of theoretical physics which is easily accepted even without direct observation - no one here has seen the Big Bang, for example. :) I think the answer to the question has more to do with personal bias than science itself. :) :)
 

Venusian Broon

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As for other planets and life elsewhere - frankly I see this as simple question as to whether someone believes life was created directly by God solely on Earth, or whether the development of life is a natural part of the universe and therefore will be found across it.

Goalposts can easily be moved in any direction, at any speed, for those with a strong bias or ideology. <Find some simple bacterial life on a moon of Saturn> - "Well, it's not complex or intelligent is it? Only Earth is special enough for intelligent, god-fearing civilisations...." blah, blah, blah ;)

Frankly I find the suggestion from any rationalist that we can't say there's life elsewhere because we haven't seen it yet quite astonishing, because that implies life is not a natural phenomenon, and additionally that the laws of physics don't work on other planets!

Frankly I find the suggestion from any rationalist that they can extrapolate from a sample of one to everywhere else quite astonishing, when they haven't hard facts to back up their beliefs. ;)

The laws of physics have been tested and observed, possibly trillions of times on the scale from the femto to the universal. :) (Sure there's loads of problems and interesting areas still to probe, but we've done a lot and we haven't seen anything, either through experimentation or observation, so far that makes us think said laws should be different elsewhere...)


Additionally, there's plenty of theoretical physics which is easily accepted even without direct observation - no one here has seen the Big Bang, for example. :) I
I find this an odd statement ;), we've loads of direct evidence and observations for the "big bang" - it's not the moment right at the start - (yeah, I'll give you that no one in this universe was taking a picture 13.8 billion years ago! :).)..No, the big bang refers to our current "best fitting to the data" model of the actual universe! Data abounds!

There are areas of theoretical physics being pondered, where we have no evidence at all for, but bite me, these are almost pseudoscience - science requires experimentation, observation and repeatable facts. I am looking at you String theory and Multiverses....

(p.s. I still think there is some value in studying such fields - after all, someone may find a way to actually test such theories at some point in the future, and it probably does pay to 'think outside the box' - I'm all for the creative spirit.)


think the answer to the question has more to do with personal bias than science itself. :) :)

Yeah, clearly :):)
 

Brian G Turner

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Frankly I find the suggestion from any rationalist that they can extrapolate from a sample of one to everywhere else quite astonishing, when they haven't hard facts to back up their beliefs. ;)

The laws of physics have been tested and observed, possibly trillions of times on the scale from the femto to the universal. :) (Sure there's loads of problems and interesting areas still to probe, but we've done a lot and we haven't seen anything, either through experimentation or observation, so far that makes us think said laws should be different elsewhere...)
But only on this planet! No one has tested whether physics works the same on another planet outside of our solar system! :D

If the same laws of physics apply, then life is perfectly feasible on other planets. If our planet is a Very Special Place and life was brought into being by Magic, then of course life might not exist elsewhere. :)

I find this an odd statement ;), we've loads of direct evidence and observations for the "big bang" - it's not the moment right at the start - (yeah, I'll give you that no one in this universe was taking a picture 13.8 billion years ago! :).)..No, the big bang refers to our current "best fitting to the data" model of the actual universe! Data abounds!
Funnily enough, we also have loads of direct evidence and observations for life. As well. :D

And, let's face it, the Big Bang model has a lot of problems. Look at the JWST observations that might double the age of the universe. How can such a well-evidenced theory be that far out? Btw I'm not saying the Big Bang didn't exist, only that any confidence in our understanding of it would be severely misplaced.

There are areas of theoretical physics being pondered, where we have no evidence at all for, but bite me, these are almost pseudoscience - science requires experimentation, observation and repeatable facts. I am looking at you String theory and Multiverses....
I'm also looking at you, Dark Energy and Dark Matter. The assumptions behind these are staggering. No wonder it's hard to actually track evidence of them. The surprise is that MOND isn't getting much more serious attention, as that can mostly wipe these out, with only the smallest tweak to relativity - allegedly: Smoking-gun evidence for modified gravity at low acceleration from Gaia observations of wide binary stars
 

Ambrose

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K2 18b is about 8 times earth mass. What effect would that have on life, even bacteria?
 

Venusian Broon

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K2 18b is about 8 times earth mass. What effect would that have on life, even bacteria?
Below a certain size, electrostatic forces have much bigger effect on animals than gravity - on Earth, it's sorta insect-size.

I'd be surprised if something much smaller, say a bacteria, would be any different in a 8g field compared to a 1g one. But that's just off the top of my head.
 

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How difficult, I wonder, would it be to develop intelligent life in a high gravity environment? I suppose the closest analogy we have on Earth is the immense pressures of the deepest part of the oceans. Life exists there but is pretty much specialised for survival in that kind of habitat. Would there be any need to develop intelligence in such a place?
 

Venusian Broon

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How difficult, I wonder, would it be to develop intelligent life in a high gravity environment? I suppose the closest analogy we have on Earth is the immense pressures of the deepest part of the oceans. Life exists there but is pretty much specialised for survival in that kind of habitat. Would there be any need to develop intelligence in such a place?

Personally I don't see why you couldn't get 'high' intelligence to develop on an ocean world. Squid and octopus seem to be on that path here for that, as a potential model, but I believe there is that thorny old issue of 'how could intelligences develop advanced technologies (such as metal working etc...) so that civilisations are more likely?'

And it may go deeper than that. Some "technologies" such as mastering fire had, I believe, a profound impact on the evolution of our ancestors - providing warmth, defence and most importantly access to cooked food. This may have led to a dramatic change in our bodies - basically: cooked food needs much less digestive organs, digestive organs are 'energy expensive' for a body to grow and maintain, so a body with a smaller gut can use that energy to build more of another energy intensive organ - the brain!* Cooked food made us smarter!

It is difficult to see how such 'intelligence positive feedback loops' might develop on a water world, but, that is Earth-centric thinking. Who's to say what different advantages and opportunities may be available to an intelligent creature in an 8g Hycean world??

===========================================
* For this argument in more depth I would thoroughly recommend the book 'Catching Fire: How Cooking Made Us Human" by Richard Wrangham - it's not a orthodox theory, after all trying to find evidence of 1 million year old campfires is a 'tad' difficult - but it is an interesting theory...
 

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The problem with octopus and squid is that they have a very short lifespan (3-5 years for a Giant Pacific Octopus and less for other types). Such a short lifespan, despite high intelligence, doesn't give an individual creature very long to develop, discover or invent things. Although we humans are less reliant on individuals for progress now, that wasn't so much the case in our earlier technological development. Any similar lifeform on another planet (I believe) would need to have a much greater lifespan and, in a harsh environment like high G, that might not be possible.
 

Venusian Broon

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But only on this planet! No one has tested whether physics works the same on another planet outside of our solar system! :D
So we should doubt every single astronomical observation that has come in from sources beyond the atmosphere of the Earth (and the moon, Mars and all the other bodies we've put probes on)? A weird position, but if you believe it, fair enough, I'm happy for you. :)

If the same laws of physics apply, then life is perfectly feasible on other planets. If our planet is a Very Special Place and life was brought into being by Magic, then of course life might not exist elsewhere. :)


Funnily enough, we also have loads of direct evidence and observations for life. As well. :D

Wow, so you have loads of evidence that abiogenesis occurred more than once on Earth?! I looked forward to you receiving your Nobel Prize soon! ;)

Seriously though, we can only point to a singular event that started it all (Hi LUCA!), therefore a discovery of another system with life that demonstrated a second abiogenesis would start to define what 'perfectly feasible' actually is in reality. Till then we are working in the dark with a blindfolds on.

(Yes, I believe that abiogenesis should occur as soon as all the right physical 'stuff', energy input and right environment come together, and I would imagine that, at the very least, the universe is fully infected with small bacteria-like life, so I'm excited to see if Mars did [or still does!], or one of the moons of Saturn/Jupiter might actually have said bugs, but I also have to admit the possibility that they might all be sterile and empty of life. That would be bitterly disappointing but it would also tell us something about abiogenesis that we didn't know before, i.e. maybe it is really quite rare after all :confused:.)


And, let's face it, the Big Bang model has a lot of problems. Look at the JWST observations that might double the age of the universe. How can such a well-evidenced theory be that far out? Btw I'm not saying the Big Bang didn't exist, only that any confidence in our understanding of it would be severely misplaced.

Never said the current leading model, Lambda-CDM, doesn't have problems. It just fits the data we have best at the moment, and the bulk of the astrophysics community are content with it, till a better model comes along.

The 'double the age of the universe' model is another big bang model that uses Lambda-CDM but it tweaks certain factors and adds in 'tired light'. It's an interesting hypothesis to discuss, but, as I'm sure you are aware, it's got quite a few flaws, and doesn't explain quite a lot of unrelated data that fits in nicely with Lambda-CDM. I'm definitely on the sceptical side that this paper is correct. I can point you to a really good video critiquing this paper if you are interested. (see below)

I'm also looking at you, Dark Energy and Dark Matter. The assumptions behind these are staggering. No wonder it's hard to actually track evidence of them. The surprise is that MOND isn't getting much more serious attention, as that can mostly wipe these out, with only the smallest tweak to relativity - allegedly: Smoking-gun evidence for modified gravity at low acceleration from Gaia observations of wide binary stars
This is a weird take for me. The whole of "Dark Matter" comes from direct and clear evidence: Rotational speeds of stars in galaxies, gravitational lensing, explanation of how the universe's galaxies came into the large filaments we see today etc... The confusion is on what is actually causing this. So rather than string theory which is strong theory/no evidence, Dark matter is unclear theory/lots of evidence. (Dark energy evidence comes from one set observations, I believe, so sits on somewhat shakier ground.)

I could go on about MOND for a long time, but trying to be succinct;), the reason it is not getting more serious attention is that it, as a class of models, they have loads of flaws and doesn't have the same explanatory power that a cold dark matter model has. Basically - and this comes from the mathematics - if one of the models of MOND is correct, then general relativity is wrong. (It's a differential equation thing, from my understanding a "general relativity MOND equation" may be mathematically impossible to construct - although of course I would interested in hearing if I'm wrong about this, because I love mathematics!:LOL:) However general relativity has been proven correct with high precision, time and time again, on many scales.

As for the observations for modified gravity you mention....other people have taken the same data of wide binary stars and they concluded that there is no evidence for MOND. There is an interesting story there, but rather than me go off yet another deep end, the same person who critiqued the tired-light model above, also did a deep dive into what is happening there too. Again if you are interested, I find Dr Becky quite clear and openminded (I'll put her other video in here too!):



Cheers!
 

Brian G Turner

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@Venusian Broon - Thank you for replying, I was worried that my aim of sounding fun and flippant just sounded ignorant and annoying. :)

So we should doubt every single astronomical observation that has come in from sources beyond the atmosphere of the Earth (and the moon, Mars and all the other bodies we've put probes on)? A weird position, but if you believe it, fair enough, I'm happy for you. :)
That's the point - I don't believe it. I believe the same laws of physics apply there as well as here on Earth. Therefore as biology seems to follow perfectly rational and scientific principles here on Earth, so it must also do so elsewhere.

Wow, so you have loads of evidence that abiogenesis occurred more than once on Earth?! I looked forward to you receiving your Nobel Prize soon! ;)
I mean that, as above, biology is a perfectly valid science. Complex life appears to have had no problem developing (in scientific terms) on Earth, therefore it cannot possibly be a freak occurrence - natural laws would not allow it. I figure the patterns we see in biological systems follow rock crystals in having an ultimate root in quantum phenomena such as fixed energy levels, etc. Hence my suggestion that the only reason we're so hesitant to accept life will have formed elsewhere isn't simply due to lack of observation, but because we still have a very strong bias to thinking that humans and the earth are unique and special.

I don't think I'm getting my point across very well - I just mean that it is inconceivable that any single natural process of physics can occur on Earth but nowhere else in the universe.

I think you get that, too, and it would be great to find existence of even microbial life elsewhere in the Solar system. The only problem is, there been so much sharing of physical material between our planets and moons (ie, meteriorites) that I think the chances of common genes is going to be high, which means some people are going to argue that any positive is going to be due to nothing more than lab contamination.

Lambda-CDM, doesn't have problems. It just fits the data we have best at the moment, and the bulk of the astrophysics community are content with it, till a better model comes along.
Yeah, it seems the overall shape of the model is fine, but my impression is that the moment you try and look at any detail of it you end up swimming in arguments and counterarguments. As you point out, there are a couple of slightly different but competing models at present. As a side point, I wonder - if observations from JWST that suggest a much older universe than we currently allow for means that Guth's Inflation would no longer be required - that always seems a bit of a weird fix.

The whole of "Dark Matter" comes from direct and clear evidence: Rotational speeds of stars in galaxies, gravitational lensing, explanation of how the universe's galaxies came into the large filaments we see today etc... The confusion is on what is actually causing this.
I think we're going to find there's far more more mass - especially gas and dust - in space than currently allowed for, both around galaxies themselves, as well as in the intergalactic medium. Not small amounts, huge amounts. But we'd probably need a radio telescope on the far side of the Moon to probably detect it as we have huge blindspots here on Earth. I've been seeing a slow trickle of science news pieces about how this might be the case for a few years now. So, to me, "cold dark matter" is just a proxy term for "gas and dust we can't yet detect" and I find the postulations of exotic matter to account for it somewhat bizarre.

That's one reason why I'm cynical about dark energy - I remember when I originally read the news in New Scientist being surprised that the authors suggested a new force in the universe to account for different observed brightness of Type 1a supernova, rather than presume that light from some was being blocked more than for others, ie more gas and dust that could normally be accounted for. Since then I'm sure I've seen reports that there's actually more variation among Type 1a supernova than originally presumed, further potentially undermining the original study's assumptions.

I could go on about MOND for a long time, but trying to be succinct;), the reason it is not getting more serious attention is that it, as a class of models, they have loads of flaws and doesn't have the same explanatory power that a cold dark matter model has. Basically - and this comes from the mathematics - if one of the models of MOND is correct, then general relativity is wrong. (It's a differential equation thing, from my understanding a "general relativity MOND equation" may be mathematically impossible to construct - although of course I would interested in hearing if I'm wrong about this, because I love mathematics!:LOL:) However general relativity has been proven correct with high precision, time and time again, on many scales.
Ah, I'm well out of my depth there - I was given the impression from the article I linked to that a lot could be solved just by a very slight tweak to relativity, without affecting most of the theory.

rather than me go off yet another deep end, the same person who critiqued the tired-light model above, also did a deep dive into what is happening there too. Again if you are interested, I find Dr Becky quite clear and openminded (I'll put her other video in here too!):
Cheers for the links, will definitely look at those later - am running out of steam for the day now!
 

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