- #1
JustinLevy
- 895
- 1
Consider a 4 dimensional spacetime which is everywhere flat and is closed in along all three spatial dimensions. Since spacetime is everywhere flat we can use global inertial frames. We will not consider any gravitational interactions in this problem.
Now a valid vacuum solution to maxwell's equations is:
[tex]\vec{A}(x,y,z,t) = -E_0 t \hat{x}[/tex]
and V=0, such that the magnetic field is zero, and the electric field is everywhere a constant.
Since the volume of this universe is finite, the energy contained in this field is constant. Now take a hydrogen atom and separate the proton and electron and let them accelerate away in this field.
Spacetime is flat so the usual maxwell's equations and lorentz force law are the same, which show that energy is everywhere locally conserved. If energy is everywhere locally conserved, and we don't have to worry about subtleties of GR, then shouldn't energy be globally conserved as well?
I've talked this over with a friend and we could only see two possibilities:
1] There is a subtle flaw in that the closed universe affects the local equations somehow (we couldn't find such a flaw, but maybe we are missing something).
2] The radiation of the accelerating charges (the radiation is also a vacuum solution), somehow collects to cancel the original constant electric field vacuum solution. But that would require the radiation to have no spatial dependence, which it of course does. So I can't see how that would work either.Any ideas anyone?
Now a valid vacuum solution to maxwell's equations is:
[tex]\vec{A}(x,y,z,t) = -E_0 t \hat{x}[/tex]
and V=0, such that the magnetic field is zero, and the electric field is everywhere a constant.
Since the volume of this universe is finite, the energy contained in this field is constant. Now take a hydrogen atom and separate the proton and electron and let them accelerate away in this field.
Spacetime is flat so the usual maxwell's equations and lorentz force law are the same, which show that energy is everywhere locally conserved. If energy is everywhere locally conserved, and we don't have to worry about subtleties of GR, then shouldn't energy be globally conserved as well?
I've talked this over with a friend and we could only see two possibilities:
1] There is a subtle flaw in that the closed universe affects the local equations somehow (we couldn't find such a flaw, but maybe we are missing something).
2] The radiation of the accelerating charges (the radiation is also a vacuum solution), somehow collects to cancel the original constant electric field vacuum solution. But that would require the radiation to have no spatial dependence, which it of course does. So I can't see how that would work either.Any ideas anyone?