Why can't light travel faster than c?

In summary: Seehttps://en.wikipedia.org/wiki/Mass_in_special_relativityIn summary, the speed of light serves as a barrier that cannot be breached by objects with mass. While some theories propose faster-than-light travel, they rely on concepts such as exotic matter which have yet to be discovered. Additionally, the idea of infinite mass for objects traveling faster than light is a simplification and not entirely accurate.
  • #36
C is what it is
Many experiments confirm this.
It could be another number. but it isn't; it's what it is

Why is it that number and not something different?. is not some thing that science can address,.
You could ask why is PI the number that it is
 
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  • #37
rootone said:
C is what it is
Many experiments confirm this.
It could be another number. but it isn't; it's what it is

Why is it that number and not something different?. is not some thing that science can address,.
You could ask why is PI the number that it is
Why pi is what it is is more fundamental. You could ask an alien civilisation and they would, once they understood what you were asking, give you the same number. The speed of light is chosen by us through our definition of the units we use.
 
  • #38
rootone said:
C is what it is Many experiments confirm this. It could be another number. but it isn't; it's what it is Why is it that number and not something different?. is not some thing that science can address,. You could ask why is PI the number that it is

The exact value of c depends on units used. It's really is not relevant to fundamental questions - although very important to applied mathematicians or physicists, engineers and such in practical applications. I explained one way to see its constant in all frames by showing it leads to magnetic fields. The second reason given is perhaps easier - according to Maxwell's equations its speed does not depend on the speed of the source.

Thanks
Bill
 
  • #39
For what the same reason you can’t outrun yourself.

Seriously? Why can’t Light travel faster than light? Nothing travels faster than itself.

Physics based responses don’t address the paradoxical nature of your question
 
  • #40
Aarav said:
Photons do not have mass, so why stop at 299700 km/s??
That’s just a number. There are units where c is just the number 1. There is a universal speed limit. It is either infinite or finite (Lorentz transformation). Experiment conforms the latter. It doesn’t matter what particular number you call that speed. Whatever it is, it is the maximim speed.
 
  • #41
Eric Bretschneider said:
For what the same reason you can’t outrun yourself.

Seriously? Why can’t Light travel faster than light? Nothing travels faster than itself.

Physics based responses don’t address the paradoxical nature of your question
Light is unique in that it has an invariant speed in all inertial reference frames (IRF).

A massive object, like you, for example will have a different speed in different reference frames.

If you are at rest in one IRF and emit a pulse of light, you measure its speed as ##c##.

In another IRF, moving with respect to the first, you will have some speed ##v##, but the light pulse will still have a speed of ##c##.

That does require an explanation.
 
  • #42
PeroK said:
Light is unique in that it has an invariant speed in all inertial reference frames (IRF).

A massive object, like you, for example will have a different speed in different reference frames.

If you are at rest in one IRF and emit a pulse of light, you measure its speed as ##c##.

In another IRF, moving with respect to the first, you will have some speed ##v##, but the light pulse will still have a speed of ##c##.

That does require an explanation.

You are still ignoring the core concept of the question. There is a logical answer that doesn’t require any physics. Replace “light” with “a horse”. Remember the c is the speed of light meaning the transformed question becomes: “why can’t a horse travel faster than the speed of a horse?”

There is no need to delve into discussions that the speed of light is constant and that it can’t travel slower or faster.

Step back and see the Forrest and not the trees.
 
  • #43
Eric Bretschneider said:
You are still ignoring the core concept of the question. There is a logical answer that doesn’t require any physics. Replace “light” with “a horse”. Remember the c is the speed of light meaning the transformed question becomes: “why can’t a horse travel faster than the speed of a horse?”
.

There is no "speed of a horse". There is a thing called a "horse race", where horses run against each other and the fastest horse wins.

A light race, on the other hand, would be a bit of a non event.

PS more scientifically, there is, for example, no such thing as the speed of an electron, although all electrons are identical.
 
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  • #44
Eric Bretschneider said:
Replace “light” with “a horse”. Remember the c is the speed of light meaning the transformed question becomes: “why can’t a horse travel faster than the speed of a horse?”
You are correct that you can play word games here. Alternatively we could discuss physics.

Why does a horse not travel faster than 30mph (or whatever its top speed is) has an answer in terms of its muscles' power output and its joint structure. It's not unreasonable to wonder if there isn't a similar answer for why light travels at 3x108m/s. There isn't, really, although you can spin the question off in many interesting directions.
 
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  • #45
Ibix said:
Why does a horse not travel faster than 30mph (or whatever its top speed is) ...

It will travel faster if you put it in a horse box and drive it along the motorway
 
  • #46
Eric Bretschneider said:
There is no need to delve into discussions that the speed of light is constant and that it can’t travel slower or faster..

Light has the strange property of being the same speed regardless of the speed of the source. Horses do not have that quirky characteristic ie if they run at 20mph on a 30mph train carriage they will be running at 50mph

Why is light so strange - well we have Maxwell's equations - but if that explains it or simply say's the same thing in a more detailed way is an interesting question (you simply notice the speed of the source is not part of the solution for EM radiation and its speed) - but more for philosophy than physics.

Another possibility is the thought experiment Einstein asked. Heuristically light waves are created because a changing electric field creates a changing magnetic field which creates a changing electric field and so on, propagating at the speed of light. Now let's get on a bike and travel at the speed of light - then the fields will not be changing - but light can only exist if they are. The solution is it travels at the same speed regardless of the speed of the bike.

Thanks
Bill
 
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  • #47
There's also the universal speed of a stationary particle. They say you can't get any slower than that.
 
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  • #48
You’re still missing the point. The question is why can’t Light travel faster than the speed of light?

Stop thinking like a physicist because anyone who asks the question has no physics background. My response is an effort to make the originator of the thread to stop and think about what they asked so that they can ask a better question.

Why can’t something travel faster than itself? It’s a ridiculous question. Why is the speed of light constant? Would be vastly better
 
  • #49
Helios said:
There's also the universal speed of a stationary particle. They say you can't get any slower than that.
That is a nonsensical statement. There is no such thing as a stationary particle in the kind of absolute terms you clearly intend.
 
  • #50
Eric Bretschneider said:
You’re still missing the point. The question is why can’t Light travel faster than the speed of light?
That is indeed the thread title, and if that were the question it would be subject to the criticism that you're directing at it. However, the body of the original post seems to clarify that the original poster is using ##c## to represent the quantity 299700 km/sec, so the question being asked is "Why that particular speed, and what limits the speed of light to that value?"
 
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  • #51
Eric Bretschneider said:
Why can’t something travel faster than itself? It’s a ridiculous question.

You supposedly have a PhD in Chemical Engineering. You should know better. The question is why can't light travel faster than C. C is the invariant speed that comes from the derivation of the Lorentz transformations I gave using group theory. The question is not why light can't travel faster than itself - the question is why can't light travel faster than the invariant speed C, which is by definition the constant velocity the same in all frames that naturally emerges in deriving the Lorentz transformations. It can't travel faster than that invariant speed because as you travel faster and faster you never catch up to it due to its invariance. Another way of looking at it is C, by definition, is the speed of light in a vacuum from a stationary source. Normal velocities go faster if their source goes faster - light does not and that's why light or anything else can't go faster than C. Its a perfectly valid question - but for some reason you chose to think its not valid. With your educational background how you made such as error beats me.

The question to ask is why is that invariant speed the speed of light. Symmetry considerations prove such a speed exists, that it is the speed of light is the follow up question which this thread has tried to answer.

Thanks
Bill
 
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  • #52
Who cares about language any more - is communication becoming a lost art because everyone tries to guess at the meaning and intent of the question?

A detailed answer to a poor question really doesn’t do anything for the person asking the question. Giving the simple answer may force them to think about their question and perhaps ask a much better question.

Consider it a version of the Socratic method of teaching with the difference that instead of asking a question, I was attempting to force someone to think more before asking a question.

To each his own. Sorry, but I have had to teach and train individuals throughout my career and forcing someone to think rather than giving a detailed answer that is well above the apparent technical level of the person who asked the question doesn’t work well.

There are some great technical answers on this thread - I DO NOT QUESTION THAT THEY ARE VALID, but if someone understood those answers they never would have asked the question in the first place.

Lorentz transformations using group theory to answer a very simple question about the speed of light? If you know Lorentz transformations you almost certainly know the speed of light is constant.
 
  • #53
This thread has run its course. It is closed.
 
<h2>1. Why can't light travel faster than c?</h2><p>According to Einstein's theory of relativity, the speed of light (c) is a fundamental constant and the maximum speed at which any object can travel in the universe. This is because as an object approaches the speed of light, its mass and energy increase infinitely, making it impossible to accelerate any further.</p><h2>2. Is there any way to make light travel faster than c?</h2><p>No, there is no known way to make light travel faster than c. Some theories propose the existence of particles called tachyons that can travel faster than light, but these have not been proven to exist and would violate the laws of physics as we know them.</p><h2>3. Why is the speed of light considered a universal speed limit?</h2><p>The speed of light is considered a universal speed limit because it is the same in all reference frames, meaning that no matter how fast an observer is moving, they will always measure the speed of light to be c. This is a fundamental principle of relativity and has been confirmed by numerous experiments.</p><h2>4. Can anything travel faster than light?</h2><p>No, according to our current understanding of physics, nothing can travel faster than light. Even if an object were to somehow reach the speed of light, it would require an infinite amount of energy to accelerate any further. This is why the speed of light is considered the ultimate speed limit in the universe.</p><h2>5. How does the speed of light affect time and space?</h2><p>The speed of light plays a crucial role in the relationship between time and space. According to relativity, the faster an object moves, the slower time passes for it. This is known as time dilation. Additionally, the concept of length contraction states that objects moving at high speeds appear to be shorter in the direction of motion. These effects are only noticeable at speeds approaching the speed of light, highlighting the significance of c in our understanding of the universe.</p>

1. Why can't light travel faster than c?

According to Einstein's theory of relativity, the speed of light (c) is a fundamental constant and the maximum speed at which any object can travel in the universe. This is because as an object approaches the speed of light, its mass and energy increase infinitely, making it impossible to accelerate any further.

2. Is there any way to make light travel faster than c?

No, there is no known way to make light travel faster than c. Some theories propose the existence of particles called tachyons that can travel faster than light, but these have not been proven to exist and would violate the laws of physics as we know them.

3. Why is the speed of light considered a universal speed limit?

The speed of light is considered a universal speed limit because it is the same in all reference frames, meaning that no matter how fast an observer is moving, they will always measure the speed of light to be c. This is a fundamental principle of relativity and has been confirmed by numerous experiments.

4. Can anything travel faster than light?

No, according to our current understanding of physics, nothing can travel faster than light. Even if an object were to somehow reach the speed of light, it would require an infinite amount of energy to accelerate any further. This is why the speed of light is considered the ultimate speed limit in the universe.

5. How does the speed of light affect time and space?

The speed of light plays a crucial role in the relationship between time and space. According to relativity, the faster an object moves, the slower time passes for it. This is known as time dilation. Additionally, the concept of length contraction states that objects moving at high speeds appear to be shorter in the direction of motion. These effects are only noticeable at speeds approaching the speed of light, highlighting the significance of c in our understanding of the universe.

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