Life on Exo Moons VS Life on Earth/Moon systems

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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 )
In our solar system formation of ice moons was pretty common in the outer solar system with the big planets.
Other solar systems with just a bit less water or more rock or location and movement of big planets and we get totally different moons and different big planets.

Still going to be a big hunt for a tech society on one of the billions of moons but I don't think such a giant hunt for life of some format and easy to detect signs of it.

Seems like far better places to hunt for life than just Earth size worlds in the HZ and the long list of needs they have.
 
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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 )
Detection of gas giants in close orbits to stars also says not to much is lost of a gas giant as it gets close to it's star.
We might have big planets alter in the HZ but i doubt a giant loss of mass.
 
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Catastrophe

The devil is in the detail
I am sure you are correct in saying that there are large numbers of planets and planets of different types. I am of the opinion that water is very common, but there will be drier examples.

We are talking millions of years for gas giants and ice moons to lose their volatiles.

Cat :)
 
I am sure you are correct in saying that there are large numbers of planets and planets of different types. I am of the opinion that water is very common, but there will be drier examples.

We are talking millions of years for gas giants and ice moons to lose their volatiles.

Cat :)
A zoo of moons.
Lots of failed moon big planet system and lots with bunches of good moons.

The randomness of the universe is sure to make most moons not able to endure the HZ heat or alteration of it's host planet.
Bigger moons Mars or bigger i think will be ok.
Far better odds for them than Earth/moon systems.
 
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Upper Paleolithic age of Siberia, Neanderthals, Genetics, Tectonics, Flynn effect, extraterrestrial impact on the evolution related ages: could be inputs for possible scenarios.
' lots with bunches of good moons ' criteria might be obtained if we start extrapolation with regression and monte carlo model for the Earth from a given point in the past.
Neanderthals thought to be a drop point of human evolution now considered to have a major percentage of DNA in our bodies now.
Other planets and moons shouldn't walk in our shoes to achieve recognizable life (longer or shorter ages as we do).
And continues to randomness for surprises in parallel.
 

Catastrophe

The devil is in the detail
I am sure you are correct in saying that there are large numbers of planets and of different types. I am of the opinion that water is very common, but there will be drier examples.

We are talking millions of years for gas giants and ice moons to lose their volatiles.

Cat :)
 
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Upper Paleolithic age of Siberia, Neanderthals, Genetics, Tectonics, Flynn effect, extraterrestrial impact on the evolution related ages: could be inputs for possible scenarios.
' lots with bunches of good moons ' criteria might be obtained if we start extrapolation with regression and monte carlo model for the Earth from a given point in the past.
Neanderthals thought to be a drop point of human evolution now considered to have a major percentage of DNA in our bodies now.
Other planets and moons shouldn't walk in our shoes to achieve recognizable life (longer or shorter ages as we do).
And continues to randomness for surprises in parallel.
Not sure life will follow any set pattern on any habitable moon/planet.
Each one will have different atmosphere/gravity/radiation etc etc leading to an entire new direction for life.

Getting to bipeds walking on solid ground then taking charge of the planet/moon.
Got to be a pretty freakish event.
Aliens might be so different to us that ET is wrongly indentified as some form of slim mold.

If we do start detecting planets/moons with signs of life we should keep an open mind that our model might not be the same as what we detect.
 
Upper Paleolithic age of Siberia, Neanderthals, Genetics, Tectonics, Flynn effect, extraterrestrial impact on the evolution related ages: could be inputs for possible scenarios.
' lots with bunches of good moons ' criteria might be obtained if we start extrapolation with regression and monte carlo model for the Earth from a given point in the past.
Neanderthals thought to be a drop point of human evolution now considered to have a major percentage of DNA in our bodies now.
Other planets and moons shouldn't walk in our shoes to achieve recognizable life (longer or shorter ages as we do).
And continues to randomness for surprises in parallel.
We can probably take an educated guess on frequency of useful moons per solar system.

If we take our 8 planets we probably have a 50/50 chance a big planet ends up in the HZ.
All 4 have decent moons that 1 or 2 would become water worlds and probably hold onto gas.
A little to close in the HZ or a little to far- lets decrease 50%.

Almost every star in the sky will have a 1 in 4 chance of a big planet in the hz and each that does will have 1 or 2 viable moons. (guess)

A betting man would gamble on those odds. :)

We have been looking for around a decade for earth size planets in the hz and have a handful of candidates.
Mars and Venus are earth size worlds in the hz and without an earth size planet with a decent size moon i think most if not all end up as one or the other.
Earth without it's moon becomes a wobbling top destined for long events of snowball earth followed by ultra hot earth and giant axis shifting wobbles.
Basic life would probably endure it but only basic fife.

A betting man wouldn't take odds on that.
 
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Catastrophe

The devil is in the detail
We can theorize all we like about how difficult, how improbable, how impossible, it must have been for mankind to be here, walking on two legs, and exhibiting (what some call) intelligence.

The fact is, however difficult, however improbable, however impossible, some may conjecture, we are here, and, at least for the time being, 'alive and kicking;.

So if the difficult, the improbable, the impossible, has happened once, why should it be so difficult to happen / have happened / happen again ??? I would suggest, on the basis of fact, not that difficult.

Look at fact, not at biased conjecture. Maybe difficult, improbable, impossible, is actually normal?

Cat :)
 
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This is an impact of thinking from another angle, if it is about an earth-like planet/moon :)

One of the astrobiology ways to define life is eukaryotes with metabolism.

A habitable zone needs energy, carbon, liquid water, a list of chemical elements for light absorbing, energy and electrochemical reactions.

Drier cases can be local habitable planets.
  • No permanent ice or snow exists on the planet. Seasonal ice and snow may exist.
  • Permanent ice or snow partially covers the planet.
  • Permanent ice or snow covers the entire surface of the planet.
  • The ice is under the surface.
Tests and simulations to formulate limits of habitability have been done, but still they have a lot of variance, even for ‘an ideal’ habitable zone shaping (for an aqua planet).

It seems, that any moon with signs of water (in any state and location) will be worth to be examined and monitored while climate changes come.
And good chance that to be normal, but not yet observed during our lifetime.
 
We can theorize all we like about how difficult, how improbable, how impossible, it must have been for mankind to be here, walking on two legs, and exhibiting (what some call) intelligence.

The fact is, however difficult, however improbable, however impossible, some may conjecture, we are here, and, at least for the time being, 'alive and kicking;.

So if the difficult, the improbable, the impossible, has happened once, why should it be so difficult to happen / have happened / happen again ??? I would suggest, on the basis of fact, not that difficult.

Look at fact, not at biased conjecture. Maybe difficult, improbable, impossible, is actually normal?

Cat :)
For sure the odds played out for our world.
Almost for sure the dice rolls will be very different on any habitable world in the universe.
We can expect life to look very different and ET to be very different.
 
This is an impact of thinking from another angle, if it is about an earth-like planet/moon :)

One of the astrobiology ways to define life is eukaryotes with metabolism.

A habitable zone needs energy, carbon, liquid water, a list of chemical elements for light absorbing, energy and electrochemical reactions.

Drier cases can be local habitable planets.
  • No permanent ice or snow exists on the planet. Seasonal ice and snow may exist.
  • Permanent ice or snow partially covers the planet.
  • Permanent ice or snow covers the entire surface of the planet.
  • The ice is under the surface.
Tests and simulations to formulate limits of habitability have been done, but still they have a lot of variance, even for ‘an ideal’ habitable zone shaping (for an aqua planet).

It seems, that any moon with signs of water (in any state and location) will be worth to be examined and monitored while climate changes come.
And good chance that to be normal, but not yet observed during our lifetime.
Yes without enough gravity to hold onto the standard gasses/water an exo moon has little to no chance for life.
Mars without the sun stripping effect would probably hold all the gasses it needs so that is my guess as minimal size exo moon for possible life.

Habitable moons can be quite a broad range of places not in the HZ, we have many of them in our solar system that could harbor life.

Moving them to the hz just changes the game of life.

Lets also not forget that tidal flexing will probably come into play with big planets with bunches of exo moons that can extend the normal HZ quite a bit.
 
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I am not sure, if this the correct thread for aliens contacting.
I was startled with my kid's (elementary school age) with a question today: 'If aliens come or we contact them, however they look like, how will we explain them all our movies, stories with seeing them as aliens and all the wars?'
I explained it as evolution thing...
 

Catastrophe

The devil is in the detail
"Lets also not forget that tidal flexing will probably come into play with big planets with bunches of exo moons that can extend the normal HZ quite a bit."

This seems safer than the extension of HZ (frost line connection) as in

The outer Solar System in 5 billion years

where possibilities are investigated as to whether expansion of the Sun will eventually bring utopia to the outer Solar System.

Cat :)
 

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