Aarav
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Photons do not have mass, so why stop at 299700 km/s??
Aarav said:Photons do not have mass, so why stop at 299700 km/s??
Yeah, a bit mathematical: all right and none answers the question!Ibix said:Heh - three answers, three completely different approaches...
They all answer bits of it. I have no idea how long a complete answer would be...fresh_42 said:Yeah, a bit mathematical: all right and none answers the question!![]()
itfitmewelltoo said:All physics theory has a point at which no further explanation can be had.
Orodruin said:Describing "why" is not the aim of physics as an empirical science.
True but that does not in any way invalidate the post to which you responded.Outhouse said:No advancements would ever be made without the curiosity to explain what no one has as of yet.
No. In modern terminology, mass refers to the invariant mass, which doesn't increase. You are referring to the relativistic mass, which is basically a confusing name for energy. This does tend to infinity as the velocity of a massive object approaches c, but a massive object cannot reach or exceed c.Fig Neutron said:Everyone please correct me if I’m wrong, but this is how my tenth grade physics book explained it. If something went faster than the speed of light it would have a negative length and an infinite mass. This was probably simplified significantly but it made sense to me.
Aarav said:Photons do not have mass, so why stop at 299700 km/s??
Outhouse said:No advancements would ever be made without the curiosity to explain what no one has as of yet.
That is a very unfortunate explanation. It is true that if you plug a speed greater than ##c## into some of the equations of special relativity you will get an impossible (not negative, but something worse - the square root of a negative number) length and mass (actually energy, but that's a longer digression). However, those equations are derived from assumptions that are equivalent to saying that no object can go faster than light so they cannot describe something moving faster than light; the absurd result is just telling you that you're trying to use the equations under conditions where they don't apply.Fig Neutron said:Everyone please correct me if I’m wrong, but this is how my tenth grade physics book explained it. If something went faster than the speed of light it would have a negative length and an infinite mass. This was probably simplified significantly but it made sense to me.
bhobba said:But what if nature does not oblige and it is a fundamental law not derivable from other laws or logically equivalent laws?
Outhouse said:and we cannot even define the fabric of space properly.
phinds said:True but that does not in any way invalidate the post to which you responded.
Nugatory said:That is a very unfortunate explanation.
Outhouse said:and we cannot even define the fabric of space properly.
I'm not aware of ANYTHING that "completes" our understanding of the nature in the universe but science extends our understanding of parts of it. I have no idea what you mean by "or are we trying to advance the theory's?"Outhouse said:Do all physics theory's complete our understanding of the nature in the universe? or are we trying to advance the theory's?
This is not really correct. See https://www.physicsforums.com/insights/classical-physics-is-wrong-fallacy/Outhouse said:many things we have had certainty on, have been overturned with new discoveries.
However, here you're making the hidden assumption, that information transmission is limited by ##c## whereas light is not. This is a circular reasoning and thus no proof: If light was faster than ##c## and we can see only as fast as ##c## then this is a contradiction.Helios said:The OP's question is answered by supposing it is true and then showing a contradiction. If light could travel faster than c, we could build a scope to see things happen earlier than when one could have otherwise seen them.
With this kind of reason you can prove everything, even the opposite.So we could make a prophecy scope, and this is a supernatural device, good for Harry Potter, but not a physics discourse.
Ibix said:We see using light.
LitleBang said:A clock on the moon runs faster than than a clock on earth.
LitleBang said:A clock on the moon runs faster than than a clock on earth.
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.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
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
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.Aarav said:Photons do not have mass, so why stop at 299700 km/s??
Light is unique in that it has an invariant speed in all inertial reference frames (IRF).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
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.
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?”
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You are correct that you can play word games here. Alternatively we could discuss physics.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?”
Ibix said:Why does a horse not travel faster than 30mph (or whatever its top speed is) ...
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..
That is a nonsensical statement. There is no such thing as a stationary particle in the kind of absolute terms you clearly intend.Helios said:There's also the universal speed of a stationary particle. They say you can't get any slower than that.
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?"Eric Bretschneider said:You’re still missing the point. The question is why can’t Light travel faster than the speed of light?