Recent content by Jens

Please show me how to derive and get the observation time dependent solution to the non-relativistic Newtonian 2-body problem (sun-earth) with gravity propagation delay = r/c. I want to understand the claimed instability!

I do not understand why propagation delay in mr"=-mM/r^2 with t replaced by t+r/c gives an unstable orbit since observation time and coordinates are delayed by the same amount. Please show the derivation and solution for the non-relativistic Newtonian case with propagating gravity.

Actually, since the final shape and elongation of the bar is stationary, one may assume the center of a small mass element dm at a distance r from the center can be expressed by r and its polar angle u. Then a given r(u) will represent the effective shape of the bar and as a function of u...

I did not talk about velocity - only revs/sec.

Ok but let's assume the bar has a length of 1 meter at rest, has rest mass M = 1 kilo and is made of steel with a circular cross section. Now assuming the angular velocity is so small and the bar so rigid that any bending and tension effects are such that the deformation remains constant after...

[Moderator's note: spun off from another thread.] How would Einstein calculate the rotational energy of a 6 kilometer long rigid bar with rest mass M rotating about its center with 15000 revolutions per second in gravity free space?

Quite a little beside the present academic discussion: How would Einstein calculate the rotational energy of a 6 kilometer long rigid bar with rest mass M rotating about its center with 15000 revolutions per second in gravity free space?