If I’m on a train that moves at the speed of light and then start going from the back to the front on the train, am I faster than the speed of light?

So you move with your train at the speed of light, which is not possible, because the energy required for the acceleration increases towards infinity.


However, if the energy increases infinitely in the four-movement[2),the remaining relative movement decreases infinitely. This is what causes time dilation.

So you can only approach the light wall, but you can’t reach it because you can’t perform the last acceleration step because you don’t have the time. Even if you had the energy. So if your train were to travel at the speed of light, it would be stuck until the end of the universe like in amber, because its energy is so high that no quantum mechanical interaction can take place. Like stuffing so many people into a room that no one comes in and no one comes out.

But let’s assume that the train is only very close to the speed of light.Which is already an achievement. After all, you want to walk around in it and look out, and not just see an inverse event horizon around the train because it’s in the light wall. As Rudiger Stolpe has already said, your movement is only faster relative to the reference system zug.

The problem is that while you might get three km/h faster than the train, the momentum required for this requires an incredibly high change in your energy at relativistic speeds.Here I have the impression that Rudiger Stolpe has overlooked something.

If the mass increases due to the increasing energy content, then the required impulse must also increase to move it.At rest, the air would not crush you, but in order to increase its momentum, as it passes through the air, further towards the velocity vector, you would have to give it the clearly increasing amount of energy visible above. Likewise, if you want to move your body towards the velocity vector. So the movement would need an enormous amount of energy.

One forms an inertial system, but the velocity addition is relativistic at this rate[3and no longer Galician.This is anti-intuitive because we know it differently, as in Rudiger Stolpe’s bus example. Air, passenger and bus form an inertial system without additional inertial forces that prevent the passenger from moving on the bus. But in the relativistic realm, the required infinitely increasing increase in energy for a further increase in speed (in the direction of rapid movement) results in an infinitely increasing inertial force. But probably only against the direction of the velocity vector! The real problem you would have is that all air molecules, blood or even solids in this direction would no longer flow or vibrate properly and are much less plastic, but in other directions they flow, vibrate and give way. Could. That would be an interesting numerical modeling of the molecules. What is the maximum relativistic inertia before air or water shows anti-intuitive effects, and flows heavier in one direction than in another direction?

Or maybe not?Somehow, it’s quite confusing.


[1 Image on wikimedia.org

[2 Four-man impulse – Wikipedia

[3 Special Theory of Relativity – Relativistic Velocity Addition

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