1. ## Misc. Unanaswerable Questions Thread

Rules: Post a question you think has no answer, if someone has an answer... Feel free to post it, if someone else feels that answer is incorrect, feel free to discuss.

2. If a woman go left or right, does time's flow divide? Is there a parallel universe formed? A thousand, for each of her turnings? As many as the stars? Is one real and the others merely shadows and reflections?

3. No.

4. Hmm... I'm inclined to say that there is only one possible reality, which is the one we are in right now, but there are indeed a multitude of plausible realities stemming from each and every moment.

Why does light have a speed limit?

5. Because that is how fast it moves. What a question, The Editor. "Why does light move at a certain speed?" "Because that is how fast it moves." That is like saying why a car going 60 mph is going 60 mph.

6. Heh, you don't get it... You see, the reason I ask the question is because everything is apparently limited to just below the speed of light, because at that point your mass is multiplied by infinity, and therefore you would require infinite energy. So far, so good. However, light (and all other eletromagnetic waves) is made up of photons, which have no mass at all, and 0x(infinity)=0. By E=m(v^2)/2 we end up with E=0 for any speed of a photon. Therefore a photon should not have a top speed. So, why does it? Does anyone know?

The reason a car travelling at 60 travels at 60 is because the forces acting on it (assuming it is not accelerating) are balanced. According to F=ma, photons have no net force acting on them and can have any acceleration they want (because m=0, therefore F=0 and a=anything you want). The car case is different.

7. Originally Posted by God
No.
You can't answer a question like that with just no... You can't know... That's sort of the point.

8. Originally Posted by The Editor
Heh, you don't get it... You see, the reason I ask the question is because everything is apparently limited to just below the speed of light, because at that point your mass is multiplied by infinity, and therefore you would require infinite energy. So far, so good. However, light (and all other eletromagnetic waves) is made up of photons, which have no mass at all, and 0x(infinity)=0. By E=m(v^2)/2 we end up with E=0 for any speed of a photon. Therefore a photon should not have a top speed. So, why does it? Does anyone know?

The reason a car travelling at 60 travels at 60 is because the forces acting on it (assuming it is not accelerating) are balanced. According to F=ma, photons have no net force acting on them and can have any acceleration they want (because m=0, therefore F=0 and a=anything you want). The car case is different.
Well that isn't light's "speed limit" then. It is just the speed at which light naturally travels, and the speed of light is everything else's speed limit.

9. What is the answer to this question?

11. But why does light travel at that speed?

12. BECAUSE GOD MADE IT THAT WAY

13. Originally Posted by The Editor
But why does light travel at that speed?
Because any faster and it will exceed the speed limit.

14. Damnit

I have been bested

15. Speed is limited by forces and kinetic energy, neither of which will limit light. Explain how there can be a "speed limit".

16. No, the speed limit is a sign sticking out of the ground that says you shouldn't go over XX miles per hour or Johnny Law kicks your ass

17. I have a better answer, it's the same one they give us for our speed limits.

The speed limits are set for everyone's safety. They are in your best interest.

18. For light?

19. Yes, if it went any faster it could be to it's own detriment.

20. According to Einstein's theory of special relativity, what we measure as the speed of light in a vacuum is actually the fundamental physical constant c. This means that all observers, regardless of their relative velocity, will always measure zero-mass particles such as photons traveling at c in a vacuum. This result means that measurements of time and velocity in different frames are no longer related simply by constant shifts, but are instead related by Poincaré transformations. These transformations have important implications:
• The relativistic momentum of a particle would increase with speed in such a way that at the speed of light an object would have infinite momentum.
• To accelerate an object of non-zero rest mass to c would require infinite time with any finite acceleration, or infinite acceleration for a finite amount of time.
• Either way, such acceleration requires infinite energy. Going beyond the speed of light in a homogeneous space would hence require more than infinite energy, which is not generally considered to be a sensible notion.
• Some observers with sub-light relative motion will disagree about which occurs first of any two events that are separated by a space-like interval.[5] In other words, any travel that is faster-than-light will be seen as traveling backwards in time in some other, equally valid, frames of reference. Therefore any theory which permits "true" FTL also has to cope with time travel and all its associated paradoxes.[6]

21. Hmm... Two things, one for each of you. First, why would it be detrimental to light to travel at a higher speed, and second, why does light itself travel at c? The article cited states that light (and indeed any electromagnetic wave) travels at c, and all particles must travel at a speed below c. However, the particles referred to all have some mass, which is not true of photons. Is there an explanation as to why c is the speed of light?

22. This means that all observers, regardless of their relative velocity, will always measure zero-mass particles such as photons traveling at c in a vacuum.
I believe that's what you are looking for. Acording to Einstein Formula C is the constant that represents light speed and any thing bigger than that wouldn't be possible (According to Einstein). Light speed is the speed of all electromagnetic radiation, including visible light. It's also very likely that C is the max speed that can be recorded (again according einstein).

Causality and information transfer

If information could travel faster than c in one reference frame, causality would be violated: in some other reference frames, the information would be received before it had been sent, so the "effect" could be observed before the "cause". Such a violation of causality has never been recorded[6].

To put it another way, information propagates to and from a point from regions defined by a light cone. The interval AB in the diagram to the right is "time-like" (that is, there is a frame of reference in which event A and event B occur at the same location in space, separated only by their occurring at different times, and if A precedes B in that frame then A precedes B in all frames: there is no frame of reference in which event A and event B occur simultaneously). Thus, it is hypothetically possible for matter (or information) to travel from A to B, so there can be a causal relationship (with A the "cause" and B the "effect").
On the other hand, the interval AC in the diagram to the right is "space-like" (that is, there is a frame of reference in which event A and event C occur simultaneously, separated only in space; see simultaneity). However, there are also frames in which A precedes C (as shown) or in which C precedes A. Barring some way of traveling faster than light, it is not possible for any matter (or information) to travel from A to C or from C to A. Thus there is no causal connection between A and C.

23. However, wikipedia also mentions an example of FTL.

The blue glow in this "swimming pool" nuclear reactor is Čerenkov radiation, emitted as a result of electrons traveling faster than the speed of light in water.

24. All those articles are doing is stating that c is a constant. They are giving no reason as to why this should be the case.

25. Originally Posted by The Editor
All those articles are doing is stating that c is a constant. They are giving no reason as to why this should be the case.
Light speed is measured as any other speed, m/s. It can travel 299, 792, 458 meters in one second. C is just a constant they use to represent light speed.

And if you are going to say why is it 299, 792, 458 meters, would be the same as saying why red is red.

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