Trapping the sun in a perfect insulator

[serp777]

So this is kind of a crazy hypothetical, but what would happen if you surrounded the sun in an invulnerable, perfectly insulating sphere that prevents anything from leaving. I imagine that as the sun heats up, the rate of fusion increases and the life time of the sun decreases. But that's about all I can say. Anyways thanks.

 

[newjerseyrunner]

Not just hypothetical, but impossible, it would violate the law of entropy.

But assuming it's possible, I think it would actually do the opposite of what you think]. If you insulated the sun, you would dramatically increase it's temperature. That would actually slow fusion, not increase it. Fusion only happens in the core, the majority of the sun is not fusing and that's what would heat up. That huge mantle would heat up and expand. That expansion would push the outer layers of the sun further from the core, meaning less gravity pulling it down. It'd actually decrease pressure on the core and slow fusion.

 

[serp777]

Not just hypothetical, but impossible, it would violate the law of entropy.

But assuming it's possible, I think it would actually do the opposite of what you think]. If you insulated the sun, you would dramatically increase it's temperature. That would actually slow fusion, not increase it. Fusion only happens in the core, the majority of the sun is not fusing and that's what would heat up. That huge mantle would heat up and expand. That expansion would push the outer layers of the sun further from the core, meaning less gravity pulling it down. It'd actually decrease pressure on the core and slow fusion.

A hypothetical is anything where you posulate an assumption to be true. But anyways say that 1 photon every million years is released so that entropy is non zero.

But if fusion stops then that means the core isn't pushing outwards against the force of gravity. Then gravity causes the fusion to restart, and i imagine it forms some equilibrium or fluctuates between the core fusing and not fusing? Also, isn't it true that the mantle can't expand that much because its trapped by the sphere?

 

[bahamagreen]

There might arrive visitors informing us that without the proper application, acceptance, and permit, what we had done to the Sun contravenes galactic policy.

 

[ogg]

I'm afraid you might not appreciate or fully understand your "hypothesis". What do you mean "perfectly insulating"? I'd guess you mean made of a material that reflects 100% of the electromagnetic radiation (emr) incident on it AND acts as a barrier to all of the solar wind colliding with it. There is no such material. There never will be such material. Matter is, by definition, electromagnetic, and so will interact with emr. And let's not even get into what about the neutrino flux, or what the size of such a sphere would be and how it would support its own mass, or...) I suppose someone who had nothing better to do could write a program to model such a thing. Of course, you didn't specify how such a thing could remain impervious to the Sun's gravity, nor what its diameter would be, but those are trivial compared to your more impossible assumptions. One of the problems is modeling this requires unphysical (magical) behavior at its surface. I'd guess that simply assuming it to be an elastic which reverses the momentum of any particle (photon, ion, or atom) hitting it might be possible...but what about the magnetic fields? Any such model can't be internally consistent, and I doubt any results could be relied upon. The rules of Logic state that a single false premise in any argument is sufficient to deduce ANY conclusion. This means if we assume 1+1 = 3 then we can prove anything (mathematically speaking) whether it's true or not. This same "you can't assume something false is true" rule holds for physics, too. Garbage in, Garbage out. Sorry. If the Sun was thermodynamically an Isolated system, it would eventually attain equilibrium. My guess is that temperature in the core would increase and you'd eventually have one heck of an explosion, but this is magical thinking, and not worth the paper I'm (not) writing it on.

 

[Drakkith]

But assuming it's possible, I think it would actually do the opposite of what you think]. If you insulated the sun, you would dramatically increase it's temperature. That would actually slow fusion, not increase it. Fusion only happens in the core, the majority of the sun is not fusing and that's what would heat up. That huge mantle would heat up and expand. That expansion would push the outer layers of the sun further from the core, meaning less gravity pulling it down. It'd actually decrease pressure on the core and slow fusion.

Hmmm. I'm not sure it would decrease the rate of fusion. Any decrease in pressure may be counteracted by an increase in temperature.

There might arrive visitors informing us that without the proper application, acceptance, and permit, what we had done to the Sun contravenes galactic policy.

I filled out the forms and sent in the 14.99, so the permit is in the mail.

 

[serp777]

I'm afraid you might not appreciate or fully understand your "hypothesis". What do you mean "perfectly insulating"? I'd guess you mean made of a material that reflects 100% of the electromagnetic radiation (emr) incident on it AND acts as a barrier to all of the solar wind colliding with it. There is no such material. There never will be such material. Matter is, by definition, electromagnetic, and so will interact with emr. And let's not even get into what about the neutrino flux, or what the size of such a sphere would be and how it would support its own mass, or...) I suppose someone who had nothing better to do could write a program to model such a thing. Of course, you didn't specify how such a thing could remain impervious to the Sun's gravity, nor what its diameter would be, but those are trivial compared to your more impossible assumptions. One of the problems is modeling this requires unphysical (magical) behavior at its surface. I'd guess that simply assuming it to be an elastic which reverses the momentum of any particle (photon, ion, or atom) hitting it might be possible...but what about the magnetic fields? Any such model can't be internally consistent, and I doubt any results could be relied upon. The rules of Logic state that a single false premise in any argument is sufficient to deduce ANY conclusion. This means if we assume 1+1 = 3 then we can prove anything (mathematically speaking) whether it's true or not. This same "you can't assume something false is true" rule holds for physics, too. Garbage in, Garbage out. Sorry. If the Sun was thermodynamically an Isolated system, it would eventually attain equilibrium. My guess is that temperature in the core would increase and you'd eventually have one heck of an explosion, but this is magical thinking, and not worth the paper I'm (not) writing it on.

It means that no energy is lost from the system. I also specified that the perfect insulator "prevents anything from leaving".

I also never said there is a material that exists with these properties. I'm not asking if its realistic. Read the op again please. I think you're confused.

"One of the problems is modeling this requires unphysical (magical) behavior at its surface. I'd guess that simply assuming it to be an elastic which reverses the momentum of any particle (photon, ion, or atom) hitting it might be possible...but what about the magnetic fields? Any such model can't be internally consistent, and I doubt any results could be relied upon. The rules of Logic state that a single false premise in any argument is sufficient to deduce ANY conclusion. This means if we assume 1+1 = 3 then we can prove anything (mathematically speaking) whether it's true or not. "

I already said that the perfect insulator, as I've defined it, "prevents anything from leaving" the system inside the sphere. That means magnetic fields, momentum, and anything else.
It isn't assuming 1 + 1 = 3 because it doesn't violate the laws of logic, it just violates material constaints. So based on this hypothetical you can assume all photons are reflected back with the same energy so that the net change in total energy of the system remains constant. Magnetic fields cannot exist outside of the sphere.

"This same "you can't assume something false is true" rule holds for physics, too. "
What are you talking about? Physicists make computer models using different constants of the universe, such as a faster acceleration of the expansion of the universe. Then they run computer models showing what happens to the universe when the constants are changed. The constants used are false, but the results of the hypothetical are still interesting.


Gravity really only has to be considered inside the sphere since a very small or zero amount of matter is lost. I don't see your problem. Other posters are still making predictions. I'm not asking you to make a perfectly consistent computer program. It is a magical sphere basically following the rule set fourth in the hypothetical. I don't care if its possible or impossible. I already know there isn't any material like that. Finally, I'm not asking you to write a paper on it.

 

[Vanadium 50]

The physics in your universe is different than the physics in ours. Because of that, it is difficult for us to predict what will happen.

 

[serp777]

The physics in your universe is different than the physics in ours. Because of that, it is difficult for us to predict what will happen.

The physics are the same except that there is a magical barrier which prevents most energy from leaving the system. What if I said that instead of a magical barrier it was a small, closed bubble of space time where expansion was equal to gravity.

 

[Drakkith]

The physics in your universe is different than the physics in ours. Because of that, it is difficult for us to predict what will happen.

It doesn't seem that difficult to me. We can certainly make some very general statements, like how the Sun would heat up until an equilibrium situation is reached. The exact details would of course require knowledge of some advanced physics.

 

[Vanadium 50]

Can you? What is the temperature of the magic barrier? What is it's heat capacity? How do you even define equilibrium in such a setup?

 

[Drakkith]

Can you? What is the temperature of the magic barrier? What is it's heat capacity? How do you even define equilibrium in such a setup?

Don't know. Perhaps you could help us work through these questions?

 

[serp777]

Can you? What is the temperature of the magic barrier? What is it's heat capacity? How do you even define equilibrium in such a setup?

Its a magical barrier. It has no temperature. If it absorbed heat then it would be draining heat from the system, which therefore means it doesn't have heat capacity. All energy that strikes the magical barrier is reflected back to the direction it came from. Because the energy is reflected back, the mantle will head up and presumably affect the rate of fusion in the core. My inclination is that the increase in temperature increases the rate of fusion, which increases the temperature, which increases the rate of fusion even more. That's just a guess though.

 

[davenn]

@Drakkith

this really belongs in the sci fi section of the forum ... there's no real science here at all

 

[serp777]

@Drakkith

this really belongs in the sci fi section of the forum ... there's no real science here at all

so fusion or solar dynamics isn't real science? Also you know sci fi means science fiction right? Sci fi is literally based on real science.

 

[davenn]

so fusion or solar dynamics isn't real science? Also you know sci fi means science fiction right? Sci fi is literally based on real science.

it is till you start introducing "magical " things and ignore real physics, then it just becomes sci fi

 

[DrClaude]

This doesn't even belong in the SciFi forum.

Thread closed.