# Moving Faster Than Light: Are There Symmetrical Rules?

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• roineust
In summary, the concept of relative motion and velocity becomes irrelevant when considering objects moving away from us at speeds higher than the speed of light. The distance between observers may appear to be increasing at a rate faster than the speed of light, but this is only a coordinate artifact and has no physical significance. Any physical insights into the situation should come from studying directly measurable invariants, such as the redshift of light signals.
roineust
Would it be correct to say, that we are moving away from stars at the edge of the universe, at the same rate that these stars are moving away from us? I am relating to stars that are moving in relation to us, at a speed that is faster than the speed of light.

Is the symmetry that maintains that if an object in space is moving away from me at a certain rate, then to all regards i am moving away from the object at the same rate, also true for objects moving away from me at a speed higher than the speed of light? Is symmetry the correct term in this context?

This question is asked for both momentary speed, for acceleration and for unnatural (hypothetically human made) constant speed.

Does modern physics assume that all theories that relate to objects moving away (or towards) us at a speed lower than the speed of light, are also correct for objects moving away from us, at speeds higher than the speed of light and that the matter of being unable to observe these objects, is just a question of non-significance in this context of theories ratification?

Nothing is "moving" relative to anything else here. The distance* between comoving observers may grow faster than the speed of light, but this has nothing to do with actual relative motion. Relative motion can only be defined locally (i.e., in a region of spacetime small enough for spacetime curvature to be negligible).

* For the particular definition of "distance" typically used in cosmology.

Orodruin said:
Nothing is "moving" relative to anything else here. The distance* between comoving observers may grow faster than the speed of light, but this has nothing to do with actual relative motion. Relative motion can only be defined locally (i.e., in a region of spacetime small enough for spacetime curvature to be negligible).

* For the particular definition of "distance" typically used in cosmology.

I will try to rephrase my questions later, according to the terminology that you use here, it might take me some time.

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roineust said:
I will try to rephrase my questions later, according to the terminology that you use here, it might take me some time.
It's not just a matter of terminology. The superluminal velocity that you're considering here is completely a coordinate artifact. It has no more physical significance, and no more can be used sensibly as a velocity, than the apparent superluminal velocity of Alpha Centauri when I sit on my porch and watch it move halfway around around a circle of radius four light-years in just one night.

Any physical insight into the situation will come from studying the directly measurable invariants, such as the redshift of light signals exchanged between us and the distant stars.

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Doc Al, PeterDonis and vanhees71
Another way to look at is that in a race between some object (with mass) and a beam of light, the beam of light will always win.

## 1. Can anything truly move faster than the speed of light?

According to Einstein's theory of relativity, the speed of light is the maximum speed at which anything can travel. Therefore, it is currently believed that nothing can move faster than the speed of light.

## 2. What are symmetrical rules in relation to moving faster than light?

Symmetrical rules refer to the concept that the laws of physics should be the same for all observers, regardless of their relative motion. This means that if an object is moving faster than the speed of light for one observer, it should appear to be moving faster than the speed of light for all observers.

## 3. Is it possible to break the speed of light barrier using advanced technology?

At this time, there is no known technology that can break the speed of light barrier. The laws of physics, including the theory of relativity, have been extensively tested and have not been proven wrong. It is believed that it would require an infinite amount of energy to accelerate an object to the speed of light, making it impossible to break this barrier.

## 4. Are there any exceptions to the rule that nothing can move faster than light?

There are some phenomena, such as the expansion of the universe, that appear to be moving faster than the speed of light. However, this is not considered a violation of the speed of light barrier as it is the space between objects that is expanding, not the objects themselves.

## 5. What are the potential consequences of breaking the speed of light barrier?

If it were possible to break the speed of light barrier, it would have significant consequences for our understanding of physics and the universe. It could potentially lead to time travel, violations of causality, and other paradoxes that are currently not possible according to our current understanding of the laws of physics.

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