Life on Exo Moons VS Life on Earth/Moon systems

Hunting for signs of life on Earth sized planets in the HZ vs hunting for life on Exo moons in the HZ.
I have a feeling we will be waiting for signs of life until Exo moons are easily detectable.
Earth/Moon systems will be very rare and have a long list of needs to be just so for life.
Earth sized Exo moons in the HZ will be numerous and already in stable climates protected from radiation/solar flares.

Thoughts?
 
VPE, I appreciate what you are saying:

"Earth/Moon systems will be very rare and have a long list of needs to be just so for life."

but, you are imposing life as we know it, as a limitation.

There may be other possibilities.

Cat :)
For sure cat, the added life as we know it :)
All we can guess on though so best guess for life, advanced life even as we don't know it i think will need things just so.
 
Intelligent life will always be a very small proportion of total life. The simplest (least evolved) organisms will always be the most abundant. This is to be expected.

Cat :)
Going to be a long hunt for places with more than ooze as the most advanced thing.
Even on Earth basic life forms will dominate this planet for 80-90% of it's possible window for life.
Got to find just the right place at just the right time seems like a daunting task to find advanced life of any format.

If our star type and quietness of it is a need for life and it needs to be in wispy arms of the galaxy in quiet non super nova county then the odds get very small indeed.

Big planets with earth sized exo moons going around red dwarfs seems the exception to the rule of a short window for life and breaks tidal locking and solar flare tantrums.

Bet if ET exists that is home. :)
 
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Still we don't know where is our intelligence and what it is.
Hence, overestimation of it cannot be scientifically proved.
But, as long as philosophy and science go close within this issue, should be considered, in my opinion.
At least we might instruct our extraterrestrial facilities with AI approaches.

If GPT-3 answers that you have 2 eyes on the left foot (fact), why not give it a try.

- Testing non-functional aspects.

Microscopic organisms would mostly have chemical transferred language.
 
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Still we don't know where is our intelligence and what it is.
Hence, overestimation of it cannot be scientifically proved.
But, as long as philosophy and science go close within this issue, should be considered, in my opinion.
At least we might instruct our extraterrestrial facilities with AI approaches.

If GPT-3 answers that you have 2 eyes on the left foot (fact), why not give it a try.

- Testing non-functional aspects.

Microscopic organisms would mostly have chemical transferred language.
Our format of life might be very freakish.
Earth/moon setups with all the bells and whistles just so is sure to be freakish.
ET might be so different from us on a world we would least expect ET to be on and that could be a normal path of life.

Extreme life living in hellish conditions on Earth seem to say that for life at least quite a broad range of conditions can be adapted to.
Worlds like Titan and frozen surface water moons are probably great places for us to look for different paths for life.
Or maybe same sorts of life that just get to a different path.
 

Catastrophe

The devil is in the detail
VPE, I agree with you. But, whatever the quirks, life is here - and that must mean a lot. You cannot say, imho, "life is virtually impossibly, absolutely a freak - and should not exist" and then add "but it is here, and absolutely all over the planet in abundance". The fact is: we are here.

Cat :)
 
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VPE, I agree with you. But, whatever the quirks, life is here - and that must mean a lot. You cannot say, imho, "life is virtually impossibly, absolutely a freak - and should not exist" and then add "but it is here, and absolutely all over the planet in abundance". The fact is: we are here.

Cat :)
For sure we will have other Earth/Moon systems going around quiet stars in the non super nova places like ours.
Lots of other just so things they will need and life almost as soon as it can or we get to Venus/Moon pretty quick.

Exo Moons of Earth size are sure to be 100s, 1000s or more common than our setup

I figure we are right on the edge of Exo Moon discoveries and in the next 10/15 years i think some interesting finds will happen all over the sky.

People tend not to think about our lucky moon much when looking for Earth sized worlds in HZ.
Without our Moon we might have life on Earth but the brutal ice ages, wobble flops of spin, stagnant oceans and general unstable climate changes would make advance life very difficult.
I think that is what we will find almost all earth sized planets in the HZ have unstable climates, we might have life on some but very basic life and all the possible window of life on them.

Exo moon Earths will have a long list of need also but not near as long.
Don't orbit to close to a big planet or you get tidal locked, huge winds we don't need.
Don't orbit to far away or flare/radiation protection decreases.
Don't orbit a really big planet that itself is a radiation creator.
Size of Exo moons not as important as Earths size is since the host planet does most of the protection, we open up a much broader range of size Moon for possible life.

Fun to think that we probably have 1000 (guess) Earthish moons for each Earth sized planet in the HZ.
Going to be fun when the discoveries start :)
 
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VPE, I agree with you. But, whatever the quirks, life is here - and that must mean a lot. You cannot say, imho, "life is virtually impossibly, absolutely a freak - and should not exist" and then add "but it is here, and absolutely all over the planet in abundance". The fact is: we are here.

Cat :)
For sure we will have other Earth/Moon systems going around quiet stars in the non super nova places like ours.
Lots of other just so things they will need and life almost as soon as it can or we get to Venus/Moon pretty quick.

Exo Moons of Earth size are sure to be 100s, 1000s or more common than our setup

I figure we are right on the edge of Exo Moon discoveries and in the next 10/15 years i think some interesting finds will happen all over the sky.

People tend not to think about our lucky moon much when looking for Earth sized worlds in HZ.
Without our Moon we might have life on Earth but the brutal ice ages, wobble flops of spin, stagnant oceans and general unstable climate changes would make advance life very difficult.
I think that is what we will find almost all earth sized planets in the HZ have unstable climates, we might have life on some but very basic life and all the possible window of life on them.

Exo moon Earths will have a long list of need also but not near as long.
Don't orbit to close to a big planet or you get tidal locked, huge winds we don't need.
Don't orbit to far away or flare/radiation protection decreases.
Don't orbit a really big planet that itself is a radiation creator.
Size of Exo moons not as important as Earths size is since the host planet does most of the protection, we open up a much broader range of size Moon for possible life.

Fun to think that we probably have 1000 (guess) Earthish moons for each Earth sized planet in the HZ.
 
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Catastrophe

The devil is in the detail
For sure we will have other Earth/Moon systems going around quiet stars in the non super nova places like ours.
Lots of other just so things they will need and life almost as soon as it can or we get to Venus/Moon pretty quick.

Exo Moons of Earth size are sure to be 100s, 1000s or more common than our setup

I figure we are right on the edge of Exo Moon discoveries and in the next 10/15 years i think some interesting finds will happen all over the sky.

People tend not to think about our lucky moon much when looking for Earth sized worlds in HZ.
Without our Moon we might have life on Earth but the brutal ice ages, wobble flops of spin, stagnant oceans and general unstable climate changes would make advance life very difficult.
I think that is what we will find almost all earth sized planets in the HZ have unstable climates, we might have life on some but very basic life and all the possible window of life on them.

Exo moon Earths will have a long list of need also but not near as long.
Don't orbit to close to a big planet or you get tidal locked, huge winds we don't need.
Don't orbit to far away or flare/radiation protection decreases.
Don't orbit a really big planet that itself is a radiation creator.
Size of Exo moons not as important as Earths size is since the host planet does most of the protection, we open up a much broader range of size Moon for possible life.

Fun to think that we probably have 1000 (guess) Earthish moons for each Earth sized planet in the HZ.
Going to be fun when the discoveries start :)
I know that it seems to defy all logic, but, life began to thrive as the Late Heavy Bombardment was ending. Almost as if life thrived amidst death and destruction. Perhaps that explains a lot of how we are now?

Cat :)
 
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Catastrophe

The devil is in the detail
For sure we will have other Earth/Moon systems going around quiet stars in the non super nova places like ours.
Lots of other just so things they will need and life almost as soon as it can or we get to Venus/Moon pretty quick.

Exo Moons of Earth size are sure to be 100s, 1000s or more common than our setup

I figure we are right on the edge of Exo Moon discoveries and in the next 10/15 years i think some interesting finds will happen all over the sky.

People tend not to think about our lucky moon much when looking for Earth sized worlds in HZ.
Without our Moon we might have life on Earth but the brutal ice ages, wobble flops of spin, stagnant oceans and general unstable climate changes would make advance life very difficult.
I think that is what we will find almost all earth sized planets in the HZ have unstable climates, we might have life on some but very basic life and all the possible window of life on them.

Exo moon Earths will have a long list of need also but not near as long.
Don't orbit to close to a big planet or you get tidal locked, huge winds we don't need.
Don't orbit to far away or flare/radiation protection decreases.
Don't orbit a really big planet that itself is a radiation creator.
Size of Exo moons not as important as Earths size is since the host planet does most of the protection, we open up a much broader range of size Moon for possible life.

Fun to think that we probably have 1000 (guess) Earthish moons for each Earth sized planet in the HZ.
Going to be fun when the discoveries start :)
Maybe I am living in the Middle Ages, but I cannot see us traversing many light years to find a new home.
Of course, I may just be blind to the future.

Cat :)
 
Chaos and destruction might be a need for advanced life
I know that it seems to defy all logic, but, life began to thrive as the Late Heavy Bombardment was ending. Almost as if life thrived amidst death and destruction. Perhaps that explains a lot of how we are now?

Cat :)
Chaos and destruction might be a need for advance life, just look at humanity for signs of that :)
 
Maybe I am living in the Middle Ages, but I cannot see us traversing many light years to find a new home.
Of course, I may just be blind to the future.

Cat :)
We might just be missing a way to travel that miles are non existent.
We are early days for sure in understanding of our universe so at some distant future what we think how quaint ideas were.
Never say never but for now it's a slow trip slowly increasing in speed over the years.
Robots on the other hand don't care how long it takes to go so if that is the limit or the limit is maybe 1/4 c then robots go multiply and go to 2 or more new locations.
Drop some dna of earth life at the new destination, babysit for a bit.
Wouldn't take that long to visit it all.

If i was a thinking robot i might leave human dna out of the mix :)
 
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IG2007

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This is an interesting question, I have to admit that.

Surely, life on exo moons or just satellites in our own solar system would be very different to life on Earth-Moon systems. Their habitats and ecosystem would obviously defer from those we have here. So, let's count them:

1. In this scenario, I am assuming that a moon won't have an ocean on their surface, and instead they have an ocean underneath the surface, and the surface is frozen. So, first of all, pressure.

Pressure would be pretty high in the ocean there, as I have to assume that just after the layer of ocean we have a hot and molten core which maintains the temperature of the ocean and the previous assumption that the surface is frigid. So, that would be a lot of pressure. But on Earth itself we have underwater aquatic animals that live in high pressure under the ocean, so that would not be a hurdle for life - and if we remember the period when the first cyanobacteria appeared and how hard it was for it to survive, we shouldn't be surprised if the same thing happens there. Yes, of course, they might not get enough amount of light from their parent star as they are under the surface but near the molten core, they might get the heat. So, the energy problem is solved, although barely. Now comes the question of intelligent lifeforms. If we consider the fact that the first multicellular organisms were found in the ocean, it would not be an outrageous claim to claim that it would happen in the same way there.

So now we have to define intelligent lifeforms exactly. To me, intelligent lifeforms are those who can adapt to different conditions, make tools and use their environment to their advantage. I didn't include "does not destroy itself" as I think I will be hypocritical if I do that (;)). Now, even if we have intelligent lifeforms beneath the ocean - they will have a really hard time. I am saying this because, they would not have access to an atmosphere which hinders them from learning aerodynamics, and therefore takes away the luxury of building rockets and discovering outer space. Moreover, they would have access to barely any wood if aquatic plants there are similar to those on Earth. And even if they have, they will barely be able to go beyond bronze age, as it would barely be possible for any iron to not rust in those conditions. Now there goes better-than-humans intelligent species in this scenario.

2. Now, to the second one. In this case, I am assuming that the exo moon is already protected of solar radiation, has a dense enough atmosphere and a stable climate and is not face-locked like our moon, as already stated by the OP. Now, I have also got to assume that the exo moon's parent planet is in the Goldilocks zone, so that it has enough heat. So, in this scenario, the moon has an ocean on the surface instead underneath it and also has a stable climate, the latter being already guaranteed in the OP.

Now, in this case, as the moon is not tidally locked, we won't have tidal waves in the ocean and therefore multicellular aquatic animals will have a different system of laying eggs or maybe they won't even lay eggs. Now, we have two scenarios within this scenario:

2.1 In this scenario, we do not have a landmass above the surface and therefore there's no chance of terrestrial life. In this case, evolution would be different compared to ours, as we have ruled out tidal waves and therefore we won't have egg-laying aquatic animals or they will have different systems of laying eggs. Now, this scenario will surely have a bad effect on reptiles and mammals will have an upper hand as I have to assume in this case that it won't take long for mammals to evolve out of reptiles as it is a pretty hostile environment for some reptile egg-laying animals and as we have already ruled out land, there won't be dinosaurs, unless you are talking about aquatic dinosaurs. Now, there might be a rivalry between aquatic dinosaurs and the aquatic mammals. Now, we never know how intelligent lifeforms might appear, but if we go by our way of evolution on Earth, we can have intelligent aquatic mammals (merpeople, anyone? ;)). For this scenario, I am just calling the intelligent aquatic lifeforms as merpeople, for reasons that I don't need to describe (;)). The merpeople might not have access to wood, if aquatic plants grow the same way there as they grew on Earth (but, who knows?), and that would be detrimental to their process of making tools. But sure, they can still make tools out of stones and bones which might still aid them. But, again, they will barely be able to go beyond bronze age as there is water everywhere. And for that reason, although they might have access to an atmosphere, they shall not learn aerodynamics and therefore they shall not build rockets and therefore they will not be able to discover outer space.

2.2 Now, this scenario is basically Earth, without tidal waves. They may or may not have plate activities. In this case, we have a very Earth-like process of evolution but with a twist. As I said in scenario 2.1, egg-laying reptiles would have a hard time and that will again lead to an early evolution of mammals and then, evolution of aquatic animals into terrestrial animals. So, maybe, maybe this is a BIG MAYBE, but maybe, we might have intelligent mammals in the age of dinosaurs. This is, again, questionable, but possible too. Now, this will have drastic outcomes. Maybe those intelligent mammals might be just like humans and survive the big reptiles and make tools and advance even more. Or, the dinosaurs will just drive those intelligent mammals to extinction and unless that exo moon's dinosaurs have the same fate as those of ours, we might have dinosaurs ruling the land and mammals ruling the water. But, if the intelligent species manage to survive, as humans survived, they might advance as far as we did and maybe even more.

So, only in scenario 2.2 can intelligent species advance past the bronze age. All of this is merely sci-fi, and if we discover exo moons with life, it is likely that we will discover scenario 2.2 exo moons earlier than the other scenarios. Sure, all of this is merely guesswork, but again, the fiction of today is the reality of tomorrow. :)
 
This is an interesting question, I have to admit that.

Surely, life on exo moons or just satellites in our own solar system would be very different to life on Earth-Moon systems. Their habitats and ecosystem would obviously defer from those we have here. So, let's count them:

1. In this scenario, I am assuming that a moon won't have an ocean on their surface, and instead they have an ocean underneath the surface, and the surface is frozen. So, first of all, pressure.

Pressure would be pretty high in the ocean there, as I have to assume that just after the layer of ocean we have a hot and molten core which maintains the temperature of the ocean and the previous assumption that the surface is frigid. So, that would be a lot of pressure. But on Earth itself we have underwater aquatic animals that live in high pressure under the ocean, so that would not be a hurdle for life - and if we remember the period when the first cyanobacteria appeared and how hard it was for it to survive, we shouldn't be surprised if the same thing happens there. Yes, of course, they might not get enough amount of light from their parent star as they are under the surface but near the molten core, they might get the heat. So, the energy problem is solved, although barely. Now comes the question of intelligent lifeforms. If we consider the fact that the first multicellular organisms were found in the ocean, it would not be an outrageous claim to claim that it would happen in the same way there.

So now we have to define intelligent lifeforms exactly. To me, intelligent lifeforms are those who can adapt to different conditions, make tools and use their environment to their advantage. I didn't include "does not destroy itself" as I think I will be hypocritical if I do that (;)). Now, even if we have intelligent lifeforms beneath the ocean - they will have a really hard time. I am saying this because, they would not have access to an atmosphere which hinders them from learning aerodynamics, and therefore takes away the luxury of building rockets and discovering outer space. Moreover, they would have access to barely any wood if aquatic plants there are similar to those on Earth. And even if they have, they will barely be able to go beyond bronze age, as it would barely be possible for any iron to not rust in those conditions. Now there goes better-than-humans intelligent species in this scenario.

2. Now, to the second one. In this case, I am assuming that the exo moon is already protected of solar radiation, has a dense enough atmosphere and a stable climate and is not face-locked like our moon, as already stated by the OP. Now, I have also got to assume that the exo moon's parent planet is in the Goldilocks zone, so that it has enough heat. So, in this scenario, the moon has an ocean on the surface instead underneath it and also has a stable climate, the latter being already guaranteed in the OP.

Now, in this case, as the moon is not tidally locked, we won't have tidal waves in the ocean and therefore multicellular aquatic animals will have a different system of laying eggs or maybe they won't even lay eggs. Now, we have two scenarios within this scenario:

2.1 In this scenario, we do not have a landmass above the surface and therefore there's no chance of terrestrial life. In this case, evolution would be different compared to ours, as we have ruled out tidal waves and therefore we won't have egg-laying aquatic animals or they will have different systems of laying eggs. Now, this scenario will surely have a bad effect on reptiles and mammals will have an upper hand as I have to assume in this case that it won't take long for mammals to evolve out of reptiles as it is a pretty hostile environment for some reptile egg-laying animals and as we have already ruled out land, there won't be dinosaurs, unless you are talking about aquatic dinosaurs. Now, there might be a rivalry between aquatic dinosaurs and the aquatic mammals. Now, we never know how intelligent lifeforms might appear, but if we go by our way of evolution on Earth, we can have intelligent aquatic mammals (merpeople, anyone? ;)). For this scenario, I am just calling the intelligent aquatic lifeforms as merpeople, for reasons that I don't need to describe (;)). The merpeople might not have access to wood, if aquatic plants grow the same way there as they grew on Earth (but, who knows?), and that would be detrimental to their process of making tools. But sure, they can still make tools out of stones and bones which might still aid them. But, again, they will barely be able to go beyond bronze age as there is water everywhere. And for that reason, although they might have access to an atmosphere, they shall not learn aerodynamics and therefore they shall not build rockets and therefore they will not be able to discover outer space.

2.2 Now, this scenario is basically Earth, without tidal waves. They may or may not have plate activities. In this case, we have a very Earth-like process of evolution but with a twist. As I said in scenario 2.1, egg-laying reptiles would have a hard time and that will again lead to an early evolution of mammals and then, evolution of aquatic animals into terrestrial animals. So, maybe, maybe this is a BIG MAYBE, but maybe, we might have intelligent mammals in the age of dinosaurs. This is, again, questionable, but possible too. Now, this will have drastic outcomes. Maybe those intelligent mammals might be just like humans and survive the big reptiles and make tools and advance even more. Or, the dinosaurs will just drive those intelligent mammals to extinction and unless that exo moon's dinosaurs have the same fate as those of ours, we might have dinosaurs ruling the land and mammals ruling the water. But, if the intelligent species manage to survive, as humans survived, they might advance as far as we did and maybe even more.

So, only in scenario 2.2 can intelligent species advance past the bronze age. All of this is merely sci-fi, and if we discover exo moons with life, it is likely that we will discover scenario 2.2 exo moons earlier than the other scenarios. Sure, all of this is merely guesswork, but again, the fiction of today is the reality of tomorrow. :)
I think for Exo moons in the HZ we are in for a wild bunch of different places and sizes of moons that will be able to support life.
We could have systems with 1-10 or more moons all with a chance for life.
All different in size and locations to the planet they orbit so wildest imagination for what we might find on any of them.

Orbiting a big planet like Jupiter i think will spell doom for it's moons.
Most if not all will get tidal locked then blasted with radiation 24/7

Maybe an earth sized moon with a good magnet field might do ok.
Even tidal locked it still has day and night cycles so weather might not be to bad and radiation levels not to bad at the surface.

I think Neptune sized worlds in the HZ will make for wonderful exotic moons with good protection, less likely to tidal lock and minor radiation from them.

Moons in our solar system in the freezer i bet will have life on a few.
Frozen above for many miles eyes probably are a useless trait if life gets that far.
My guess basic life forms in the oceans on a few.
Titan another mystery, 4+ billion years of alien lakes but very very cold, will basic life try then adapt or is it just to cold.

Finding some sort of life in our solar system that has nothing to do with our dna i think would be an eye opener to the universe.
Finding life based on our dna would also show that at least in our solar system life spread and probably made it's way to a few stars around us.

Advice don't sleep on the Forest Moon of Endor (natives tend to eat those that fall asleep ) :)

P.S great post above IG , i enjoyed reading it.
 
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Just a quick thought on escape velocity.
In the HZ Exo Moons i think we will still need moons to be a pretty decent size.
Ice will be gone or all but gone in the hz to protect oceans.
Loosing an atmosphere won't happen like it does directly orbiting a star but i think moons gravity will need to be something big enough to hold onto noble gasses.
Mars of bigger maybe?

We would need a formula to figure it out with every planet size/moon size, radiation load, star temper tantrum etc.

That one might take a lifetime.
 
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In some cases, if the ice goes, there may be nothing left.

Cat :)
For sure going to limit a minimum size a moon can be in the HZ and be a possible for life.
They won't be as bad as a smaller than earth orbiting the sun but for sure a minimum size to hold onto nitrogen, oxygen, carbon dioxide.
We do get a decent protection of the suns atmosphere striping inside the host planet magnetic field.

Mars if it had a magnetic field like earth or stronger would be habitable so my guess is things a bit smaller than mars as an exo moon but not much smaller.

Thoughts?
 
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IG2007

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My guess is that moons sized anywhere between Mars and Earth ( or maybe even bigger than that, who knows?) can be habitable. But only if they have a magnetic protection around them. :)
 
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My guess is that moons sized anywhere between Mars and Earth ( or maybe even bigger than that, who knows?) can be habitable. But only if they have a magnetic protection around them. :)
I'm not sure Exo moons will need a strong magnetic field for protection.
Inside the host planets magnetic field they wont get atmosphere stripped, or very minimal.
Size for sure is going to be important and as long as they can keep water and a few noble gasses they are set to be places for life.
 
For outer SS moons, size does not matter if they are 90+% water ice. Even Jupiter, if you warmed off the hydrogen, would only be about 4 x Earth diameter. Jupiter!

Cat :)
Makes you wonder how many Jupiter like planets ended up in the HZ around the galaxy and now are Neptune size worlds with a bunch of well protected water moons.

I think even red dwarf solar flare tantrums would get pretty good protection and be tidal lock avoided from the red dwarf.
Even tidal locked to it's host planet Exo moons will still get day and night cycles.
Could be some very weird days and nights though :)

Red dwarfs being possible locations for life sure opens a vast number of stars up for life.
 
"set to be places for life." which will not survive temperature increase on two counts (1) they will melt )2) their gas giant will melt and they will be lost.

Cat :)
If we placed Jupiter and it's moon set at Earths location.
Sure we have some shrinkage of Jupiter but the magnetic field stays pretty strong.
All the moons melt and reside in that magnetic field.
Then it comes down to escape velocity of noble gasses and water on each moon.
Little to no atmosphere stripping from the sun though.

Hard to say what happens to Jupiter's moons in that scenario.
Some for sure will be just to small to keep what they have and some will be big enough.
Jupiter is a pretty nasty place to be inside the magnetic field anyway so shrinkage isn't a bad thing :)
 
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Catastrophe

The devil is in the detail
Shrinkage of Jupiter will coincide with melting of ice - life developing on water worlds has limited technology (nothing electrical) - habitation by us limited to floating and/or submarine structures - but also loss of mass by Jupiter (or any gas giant) will affect moon orbits, almost certainly causing loss of moons, or at the very least causing insecure orbits.

As the habitation zone slowly extends to include Jupiter, it will take probably millions of years for the ice to melt and the H/He etc to dissipate. (After ~5 billion years, how long does it take for the Sun to expand - I need to check this and look at this again.)

In approximately 5 billion years, the sun will begin the helium-burning process, turning into a red giant star. When it expands, its outer layers will consume Mercury and Venus, and reach Earth.27 Mar 2018
Red Giant Stars: Facts, Definition & the Future of the Sun | Space

Doesn't say how long between starting and ending expansion phase, BUT . . . . . . . . .


Will Earth survive when the sun becomes a red giant? - Phys.org
https://phys.org › Astronomy & Space › Astronomy


"When the sun does begin to expand, it will do so quickly, sweeping through the inner solar system in just 5 million years.

It will then enter its relatively brief (130 million year) helium-burning phase, at which point, it will expand past the orbit of Mercury, and then Venus. By the time it approaches the Earth, it will be losing 4.9 x 1020 tonnes of mass every year (8 percent the mass of the Earth)"



Cat )
 
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