# Living inside a star

Discussion in 'Astronomy, Exobiology, & Cosmology' started by orcot, Apr 25, 2018.

1. ### orcotValued Senior Member

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3,488
I've recently listened to one of isaac arthurs podcast and now I'm wondering could a civilization actually survive inside a star?

In short
in our star? No surface tempratures are 5700°K and the gravity at the relative surface would be 27,94G
Now let's say proxima centauri (the closest star except our sun and a whole lot smaller)? (info)
The surface temprature is only 3042°K this is warm but but theirs a great many materials that can actually survive these temprature. (source)
most promising are thungsten and carbon. There is actually quit a list but many are either radioactive or extremly rare. That said the myth that if you would trow something inside a sun and it would yust vaporize is not absolute.
Gravity whilst our sun would provide 27,95G of gravity a 50kg person would weight 1397,5 kg (a 100kg person would weight 2795kg) the relative surface gravity from proxima centauri would be
0,052 m/s² meaning a 50kg person would weight 0,26kg a 100kg person would weight 0,53kg.
So okay you could build it and it would last and you could pravticly float in it. But the interior would eventually equalize with the exterior making it 3000°K inside (you cook)
looking at the thermal propperties for tungsten it's around 173 W/(m·K) for comparison iron80.4 W/(m·K), copper 401 W/(m·K) and aerogel 25 mW/(m·K). But even if it was 0 you would evcentually cook because of people also radiate heat.
That said you could make poles (space elevators) that end in a solar sail the sail would mean that you aren't bound to orbital speeds meaning the elevators could be much shorter and the other shadow side could be used to radiate the internal heat away.

So if not impossible what would you do there why make the effort. Basicly you have a near infinite amount of heat (energy) and mass that could be used to make heavier elements. Basicly you can do the things that stars do and turn lighter elements in whatever you need both on the periodic table and anti matter.

Do you think this would be plausible or do you think theirs easier ways to get near infinite mass.

3. ### exchemistValued Senior Member

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10,929
No. Bear in mind also that a star is a continuous H BOMB!!! Just think of the radiation flux! You'd be fried by atomic particle bombardment. And regarding the heat, the only way you would be able to sustain a temperature for living lower than that around you would be to have some kind of heat pump that could export heat into space at a temperature even hotter than the sun's!

Far better, surely, to live in buried communities on a nearby planet (like Mercury), harvest the intense energy flux available there and use the shadow of the planet's side away from the sun for re-radiating unwanted heat from the living areas off into space.

5. ### orcotValued Senior Member

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3,488
Yes that would be a first idea
But for a other idea. Isn't there a trick with pressure? With the combinend gas law? Basicly you stpre the heat in a undefined mass and increase the pressure to increase the temprature to well over the exterior temprature. You place the superheated material outside where it can cool down to the steller enviroment to the still hot 3000°K You bring the material back inside and you suddenly have the same mass but a lower temprature

First their needs to be a planet like Mercury avaible. Second wouldn't something like a o neil cilinder yust be better? you could place it with a solid rear end facing the star and use a mirror that only reflects the visible spectrum infra red and radio towards the opening. There is no risk for earthquakes. There is simply no risk of contaminating live. Your solar powered industry that could make extreme products like anti matter for star ships could explode and you would be safe.
Inhabiting a planet, it's like inhabiting a cave inside a mountain O neil cylinders are the equivalent of breaking down the mountain to make appartments. Their certainly will be a place for planets and I hope that if ever we visit the stars that at we terraform at least 1 in 100 planets (not with intilligent species though But definitly prepped that if left undisturbed intilligent life would almost certainly not appear with the first 20 million years but almost definitly within a 100 million years). Worlds with intelligent species like Neanderthals, other human ancestors, antrophomorphed existing creatures (for example squids with greatly increased lifespans and capable to move on land), or things of our own design should also be build but digitally. So that we are able to mess with time.)
Anyway O neil cylinders seem safer cheaper and more uniform. Honnestly I believe people that will live extended periods on the moon or mars will have problems returning and adjusting to earths gravity for example. Whilst the longer orbit of places like mars would create a chism between inhabitants of mars and earth in a simple things like number of birthdays and holidays.

7. ### orcotValued Senior Member

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3,488
So if we assume the tungsten outer hull survives the outside conditions The inside of the ship would look a bids like the filament of a Incadesent lightbulb (warm yellow orange). I imagen that if you then constructed a second hull with in between either a couple of options. If you placed a vacuum in between you would only have black body radiation. Similar in color and output as a lightbulb. Considering the size of the craft even if it could not permanently stay under it could probably last some time until it needs to resurface and hide behind a shade to cool down. Ideally the second hull would take use of the temprature gradiënt to to feed a either a fusion device that can turn the elementel hydrogen in the desired element. Or otherwise it's yust a scoop boat that dives in collects billions of tons of hydrogen. And use part of the mass to speed up and escape the gravity well to end up in orbit where solar collectors can turn the elements in their desired element under less harsh conditions. Altough you would imagen that a hot Jupiter would be more suitable. And perhaps even any regular gas giant like neptune and Uranus if you can lower a platform inside the atmosphere that then uses the hydrogen gas to produce fusion and uses that fusion energy to make desired elements you can then beam these hot heavy elements outside the gas Giants gravity well where you can collect them and cool them. the drawback here is that you have a deadly partical beam that can be aimed to earth.
especially for the solar system there is only one safe place to build such a particle accelerator and that is the backside of the moon. (It never faces earth. Even if you decide to be clever and launch it in the opposide direction. You could see it hours afther launch for earth and you have 6 months to put something in it's way If you launch it fasther it will yust be in a wrong orbit and miss you completly.

8. ### DaveC426913Valued Senior Member

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16,190
Why go to all the trouble of trying to live inside a star, when you can't do it for more than a very short time before you have to leave again?

Why not simply orbit the star? You can get as much energy as you want, you don't have to worry about pressure, and you can simply move to a higher orbit when you need to vent heat.

The cost/benefit ratio of being in a star versus being proximal to a star is virtually zero.

9. ### orcotValued Senior Member

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3,488
It's a interesting subject. Why not, why live in orbit, or on Mars? If you think abouth it is suddenly doesn't get that impossible.
Their are a few genuine reasons.
1 it could simply be the only object around (not all stars have planets)
2 you could hold all worlds ass nature reserves. Or test beds I can't imagen never trying to terraform mars and it being by definition both a succes and a failure large masses of land will be submerged and the entire thing will be prone to flash floods because theirs no natural drainage system and the the underground would be melting for thousands of years. collapsing entire regions sometimes below sea level.
3 Storage of dangerous materials. Imagen being a kardashev 2 civilization and you need to store large amounds of anti matter in a relative busy solar system. If you store them on a planet you risk that planet if you store them in space then they are a open target for everyone, store them in deepspace and it takes to long to fetch them (under known physics), store then in a asteroid or low mass object and you have the risk of a runaway Kessler syndrome but on a scale of a solar system.
4 stealth and second strike capabilities. Men's biggest foe is man itself You can time a attack to take out all enemy settlements in 1 go but good luck hitting something that is below the surface of a star
5 consistent output mining. You scoop up hydrogen gas and you fuse it in whatever element you like. The same miner that will deliver you tungsten can yust as easly deliver lithium it all starts as hydrogen. then their are the rare earth elements try finding them consistantly. Sure they are out there but surveying and limited mining will cause for unstable pricing. Then you might think well I yust take the something sort of my element and fuse it on situ. But then you have to pack all that energy with you on site (that's a big bomb)and the heat you radiate out could cause problems.
why combine near limitless energy with near limitless mass? They make a great combo