Wednesday, May 25, 2016

equivalence between gravity and inertia

equivalence between gravitational and inertial forces implies that all inertial forces are identical to gravity and in fact generated by a transformation of the metric field of a matter distribution relative to which one accelerates a frame of reference. can you outline a setup where one replaces e.g. the Coriolis-force by a gravitational field?

Wednesday, May 18, 2016

interstellar (the movie)

the astronauts in the movie "interstellar" use rotation of their space ship to generate artificial gravity by means of a centrifugal force. would there be a way to distinguish the two? if inertial and gravitational forces are indistinguishable, how would you explain that the artifical gravity onboard the space ship is in fact actual gravity, i.e. what generates this gravitational field? if space was completely devoid of matter, would that still work?

Wednesday, May 11, 2016

underdetermined electrodynamics?

following up on last week's post: is there a similar problem in electrodynamics because one sources 6  components of the field tensor from just 4 components of the charge current density?

Wednesday, May 4, 2016

underdetermined general relativity?

the Riemann curvature tensor has in 4 dimension 20 entries, but the field equation of general relativity only links the 10 entries of the Ricci-tensor to the energy-momentum tensor. what determines the remaining 10 entries of the Riemann curvature?