Hi,
In Fourier analysis, we can decompose a function into sine waves with different wavenumbers that travel at different speeds (i.e., for a given wavenumber k they can have different frequencies ω and therefore different speeds v = ω/k). There is no upper bound on the speed of propagation v...
I'm not sure one should expect a continuous-media theory to give incorrect results when the limit is taken as the size of a distribution goes to zero. To me, that is analogous to saying that general relativity shouldn't give the correct results in the limit of flat spacetime because it is a...
Hi,
I have been studying the radiation reaction problem and I see a weakness in the derivation that hopefully someone might illuminate for me. In the textbooks by Griffiths and Jackson, as well as some journal articles I have found, the radiation reaction seems to be "derived" by a suggestion...
Thanks, everyone. Your responses and links helped to settle it in my mind in different ways (at least settle it as much as might be done without a bit of time for some of the information to sink in). Although if anyone wants to add something else, of course feel free to do so!
Thank you both for your responses, and also for the welcome from bcrowell :)
bcrowell, I might have been a imprecise out of ignorance, but when I say "metric" I really do mean a scalar. From http://en.wikipedia.org/wiki/Metric_tensor" :
So what I mean by "metric" in those terms is the...
Hi,
I have been wondering if there is a Lorentz-invariant quantity that satisfies the definition of a metric for space-time.
The space-time interval s2 = t2 - r2 [where r is the vector (x,y,z)] does not satisfy the requirement for a metric m that m(t1,r1, t2,r2) = 0 if and only if (t1,r1)...