length expansion

  We looked at the Ehrenfest paradox last time. There are two issues in the Ehrenfest paradox. The first assumes a disc made up of an ideal rigid body, but when rotated at relativistic speed, it ruptures. The second is that the perimeter of a rotating body is different from its length when it is stationary. In the last post I looked at the first issue, and this time I want to look at the second issue. For those who have not read the first part, I will briefly introduce this paradox. It is best to read the previous post. Below is a link to the first part. The Ehrenfest paradox part I Rotating disc and length contraction   In relativity, objects that run very fast are said to shrink in length. So the official name of this is Lorentz - Fitzgerald Length contraction. It is not 'Einstein's length contraction'. This was born regardless of the theory of relativity. Before the theory of relativity was published, several people experimented to detect ether, but the...

  Black holes are unusual in many ways. Thet have also has a spinning disc, a jet, a Schwartzchild radius, a horizon of events and singularities. But there is one thing that can not be explained in modern science or the theory of relativity. It is the rotating disc of a black hole. Black hole and Ehrenfest paradox   The speed at which materials rotate in the rotating disk of a black hole is almost as close as the speed of light. If so, all the materials must be decomposed and discarded by the Lorentz contraction. However, the rotating disk of a black hole certainly exists. It is definitely a contradiction. In fact, these are linked to the famous paradox of the Ehrenfest paradox. [1] Today, we will look at the Ehrenfest paradox. Fig. 1 Paul Ehrenfest Personally, I think Erlenpest paradox is the best of relativity's paradoxes. Other paradoxes seem to be a little simpler than this paradox. The list of people who studied this paradox is very extensive. Ein...