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Again gravity is what maintains the reaction going, without it the gas would expand and the reaction would stop. I understand how fusion works, what you neglec

Again gravity is what maintains the reaction going, without it the gas would expand and the reaction would stop. I understand how fusion works, what you neglect is that gravity is what allows you to counter the nuclear forces to cause protons to fuse in the first place, and what keeps the entire thing from blowing out. Hence stars are in constant balance between gravitational collapse and their outward pressure caused by fusion. “An interstellar cloud of gas will remain in hydrostatic equilibrium as long as the kinetic energy of the gas pressure is in balance with the potential energy of the internal gravitational force. Mathematically this is expressed using the virial theorem, which states that, to maintain equilibrium, the gravitational potential energy must equal twice the internal thermal energy.” On earth we exchange gravitational potential with electromagnetism but we still need to apply the same force to counter the nuclear forces and the pressure from the reaction once it starts. All I want to know is if we have a proven net positive model for this reaction because so far I haven’t been able to find one. Because as far as I know the vital theroem stands so it doesn’t matter if it’s gravitational potential or any other force it still needs to be twice the thermal energy of the reaction. But you can continue to downvote without actually addressing anything while ingoring everything we know about stellar fusion and the fact that is triggered and constantly maintained by gravitational collapse. So no I don’t ignore the role of gunpowder in a gun, you ignore the energy needed to create the gunpowder and cartridge in the first place. That's the best I can do for you. Good luck!

theothermkn 8y ago
"...the fact that is triggered and constantly maintained by gravitational collapse." What you have written is not a fact. Forces only do work when they act through a distance. Gravitational potential energy only comes into play during the ignition of a star. After equilibrium is reached, to the extent that the star's diameter is "static" potential energy calculations no longer come into play. No "potential energy" is being "converted" into fusion energy. It's just not a thing. "...stars are in constant balance between gravitational collapse and their outward pressure caused by fusion." Because of this balance, no work is being done by gravity. That is, no energy is being released by the force of gravity moving a mass through a distance. "All I want to know is if we have a proven net positive model for this reaction because so far I haven’t been able to find one." It's literally E = mc^2, but it's not "net positive." It's net zero. Matter is converted into energy. That's it. "So no I don’t ignore the role of gunpowder in a gun,..." It's an analogy, and it's straightforward enough that the onus is on you to work out the pieces a little better than you have. HINT: The "energy needed to create the gunpowder..." is the binding energy in the various nuclei.
- dogma1138 8y ago
  >Because of this balance, no work is being done by gravity. That is, no energy is being released by the force of gravity moving a mass through a distance. I didn’t say it extracts energy from gravity, gravity is constant and it is what keeps the reaction going. This balance is dynamic equilibrium, gravity continues to counter the gas and radiation pressure of the star’s fusion reaction if you remove gravity from the equation fusion stops because the pressure would cause it to expand until the reaction stops. If the reaction slows down then the collapse continues until fusion of heavier elements can happen, degenerate pressure can counter it or if neither of those happen you get a black hole. >It's literally E = mc^2, but it's not "net positive." It's net zero. Matter is converted into energy. That's it. I didn’t ask you how much energy any given unit of mass has, I asked you for a net positive model for a fusion reaction. We need to invest energy to make fusion happen then we need to invest more energy to keep the reaction going. So again I understand where the “excess” energy comes form when two protons fuse into a neutron, however proton fusion isn’t spontaneous and it requires you to expand energy to bring them close enough so they could fuse. Now in say hydrogen plasma you need to overcome a lot of forces to do that, and more so when the reaction starts since the energy release wants to expand the plasma outwards what I want is to see a net positive model for this reaction. So far I only hear crickets.
  - theothermkn 8y ago
    No energy is being continuously invested by gravity. It is not "keeping the reaction going" in that sense. It's simply freshman physics that tells us that forces only do work when they act through a distance. Because the star's surface is not moving inward, it is not doing work, i.e., giving energy, to the star. Furthermore, the Sun, for example, is probably slowly expanding right now. It will start to do so in time, at any rate. That is, the work done by gravity on the Sun will be negative during that time, and fusion will continue. You just aren't making any sense. You are either not trained in physics, or have failed to understand what you have learned. You could begin to piece together a better education in it by simply following up on my replies in this thread. Please, take it from me, you do not know what you are talking about, and your concerns are therefore not valid. I thought I could help, but you seem to be a tough case. In short: Forces only do work by acting through a distance. Work is energy. If no work is being done, no energy is being produced. Therefore, gravity is not "energizing" the reaction, because the net motion of the star towards its center is zero when it is in equilibrium. In shorter: No motion => no work. No work => no energy. No energy => no problem.

theothermkn 8y ago

"...the fact that is triggered and constantly maintained by gravitational collapse." What you have written is not a fact. Forces only do work when they act through a distance. Gravitational potential energy only comes into play during the ignition of a star. After equilibrium is reached, to the extent that the star's diameter is "static" potential energy calculations no longer come into play. No "potential energy" is being "converted" into fusion energy. It's just not a thing. "...stars are in constant balance between gravitational collapse and their outward pressure caused by fusion." Because of this balance, no work is being done by gravity. That is, no energy is being released by the force of gravity moving a mass through a distance. "All I want to know is if we have a proven net positive model for this reaction because so far I haven’t been able to find one." It's literally E = mc^2, but it's not "net positive." It's net zero. Matter is converted into energy. That's it. "So no I don’t ignore the role of gunpowder in a gun,..." It's an analogy, and it's straightforward enough that the onus is on you to work out the pieces a little better than you have. HINT: The "energy needed to create the gunpowder..." is the binding energy in the various nuclei.

dogma1138 8y ago
>Because of this balance, no work is being done by gravity. That is, no energy is being released by the force of gravity moving a mass through a distance. I didn’t say it extracts energy from gravity, gravity is constant and it is what keeps the reaction going. This balance is dynamic equilibrium, gravity continues to counter the gas and radiation pressure of the star’s fusion reaction if you remove gravity from the equation fusion stops because the pressure would cause it to expand until the reaction stops. If the reaction slows down then the collapse continues until fusion of heavier elements can happen, degenerate pressure can counter it or if neither of those happen you get a black hole. >It's literally E = mc^2, but it's not "net positive." It's net zero. Matter is converted into energy. That's it. I didn’t ask you how much energy any given unit of mass has, I asked you for a net positive model for a fusion reaction. We need to invest energy to make fusion happen then we need to invest more energy to keep the reaction going. So again I understand where the “excess” energy comes form when two protons fuse into a neutron, however proton fusion isn’t spontaneous and it requires you to expand energy to bring them close enough so they could fuse. Now in say hydrogen plasma you need to overcome a lot of forces to do that, and more so when the reaction starts since the energy release wants to expand the plasma outwards what I want is to see a net positive model for this reaction. So far I only hear crickets.
- theothermkn 8y ago
  No energy is being continuously invested by gravity. It is not "keeping the reaction going" in that sense. It's simply freshman physics that tells us that forces only do work when they act through a distance. Because the star's surface is not moving inward, it is not doing work, i.e., giving energy, to the star. Furthermore, the Sun, for example, is probably slowly expanding right now. It will start to do so in time, at any rate. That is, the work done by gravity on the Sun will be negative during that time, and fusion will continue. You just aren't making any sense. You are either not trained in physics, or have failed to understand what you have learned. You could begin to piece together a better education in it by simply following up on my replies in this thread. Please, take it from me, you do not know what you are talking about, and your concerns are therefore not valid. I thought I could help, but you seem to be a tough case. In short: Forces only do work by acting through a distance. Work is energy. If no work is being done, no energy is being produced. Therefore, gravity is not "energizing" the reaction, because the net motion of the star towards its center is zero when it is in equilibrium. In shorter: No motion => no work. No work => no energy. No energy => no problem.