length expansion

Hello    Today, I would like to take a look at the questions posted at https://physics.stackexchange.com/. The contents are as follows. There is an iron bridge. This bridge cannot withstand the weight of the entire train, but if it only has to support part of the train as shown in Figure 1 below, it can do it. Figure 1. Non-relativistic consideration, if only a part of the train is on the iron bridge, the iron bridge will not collapse Therefore, when the train runs slowly, it is placed only on a part of the bridge, so the bridge does not collapse. (Click below to see the original.) However, if the length contraction is correct, it will be as shown in Figure 2 below. The train is contracted, the entire train is placed on the bridge, and the bridge must collapse. Figure 2. When the observer on the ground sees it, the entire train has come up and the iron bridge must collapse (Length contraction) However, from the standpoint of the perso...

   The time dilation effect in relativity is well organized. It is well-formulated and conceptually well-documented, and has proven to be very robust in experimental terms. However, length contraction is not so. The mechanism by which length contraction occurs is unknown even if everything else is aside. So here we have to think about the mechanism of length contraction. Three expected mechanisms of length contraction There are three ball-like particles arranged side by side. It's still inactive. Therefore, they did not change the length at all. Let's assume that they are the same and the spacing between them is constant. Now let's see what happens when these particles run fast. The picture and contents below are referenced at http://www.alternativephysics.org/book/LengthContraction.htm .  There are three ways to predict the length contraction mechanism. Fig. 1 Stationary particles When particles run at relativistic speeds, length contraction will...

  In an inertial system, the speed of light is always constant. It is a very short sentence, but today this proposition is not fully understood. If you thoroughly understand and adhere to two principles of relativity theory, the   principle of relativity and the constancy of the speed of light , you can naturally conclude against a reasonable relativistic length. If we keep these two principles constant, without preliminarily setting a conclusion about length, we can make a surprising discovery. Especially about length. The two principles of special relativity theory speak about symmetry and conservation. The first principle, the principle of relativity, says that all inertial systems are symmetrical to each other, and the second principle, the constancy of speed of light, says that the light speed is always preserved. At first glance, these two principles seem to oppose each other. However, if these two principles work in harmony, you get amazing conclusions. After...

     Hello. Today we will look at Bell's space paradox. Relativity has a lot to do with common sense. Changes in length, time, and mass are also exciting, but there are many paradoxes that are hard to understand logically. I think the most disturbing thing is the "Bell's spaceship paradox" . In general, the paradox of relativity can have various opinions. Until someone has experimentally verified it, it is difficult to judge who is right. Experimentation of relativity theory must be done in extreme environments, so it is difficult to see even if there are various opinions. But today's talk about Bell's space paradox is a bit different. In this paradoxical story, even if only the experiment of thought is carried out, the obvious logical flaw is revealed. Bell's paradox is this. There are two spaceships on the Earth's hangar. The specifications of these two spaceships are the same, and the pilots are twins, so all conditions are the same. ...