Speed of light is a universal constant

[Danger]

Danger, not meaning to pick a fight (more so to pick nits)

It's not even nit-picking, m'man; we're referring to different aspects of the same things. The values, as I employ the term, are fundamental aspects of space-time. The numerical definitions of those values are completely fabricated. Light speed can be 286,282 mps or 300,000 kps or 1,9435,354.45 kurps per mlank (if you're a Rigel 7 mud-tumbler). No matter what anyone calls it, it doesn't change the physical aspects of it.

 

[Dr.Brain]

What is light?

Its having both wave and particle nature. Hard core facts---- it consists of certain particles which we named as photons and the quantum physics has proved its existence.Then optical phenomenon like diffraction, interference, refraction,polarization etc have proved its wave nature…they are TRUE properties of light but cannot be quantified.

Speed of light is NOT its internal property like the size or mass of any particle…it is something which is a variable quantity that is different from the constituents of light..it’s a PHENOMENON…a phenomenon is changeable but the internal properties are not…

Basically, what you are trying to imply is that we need to forget relativity for the timebeing and believe in your facts.

Your text says that (forgetting relativity) , light's speed or infact velocity of any particle is not intrinsic property at all, not depending on its internal features.

In a particular inertial reference frame , no doubt the size of an object remains same (but different from the original size in a stationary frame of reference), but the velocity is variable and it does not depend on its internal features is certainly not quite digestible.

Lets say we are in a particular fixed stationary reference frame and we are observing a phenomena:

Take for example, a light ray in vacuum with velocity 'c' , it enters into a medium ,for example glass , now the photons are no doubt form the internal features of light, these photons are traveling at the speed of light in vacuum , now the light enters into a glass slab, now the photons in the glass will still move at the same speed 'c' but they are being obstructed every now and then , due to frequent collisions with the atoms of the medium and as a result it seems to us that light ray as a whole has slowed down a bit, so light ray slows down in a medium due to obstructed motions of the photons , which are ofcourse internal.

I might have agreed to you if you had said that 'light can have two different speeds at two different instants due to change in medium in the same inertial reference frame" , but I certainly do not agree that 'velocity is variable and
mass remains constant.Mass is a quantity which changes with velocity if we take into consideration one particular particle/object.

 

[Kazza_765]

i am talking of a single ref frame...say Earth (as an isolated system) in that ref frame when we measure size of a stationary atom, it remains same but speed need not be if its moving and that depends on the energy its having. now both this const and variable i,e length/mass and vel resp. change wrt some other ref frame...but remember that vel can be variable even in the ref frame where the length is not ...so length/mass and vel are NOT comparable

Length and mass are only constant if velocity is constant. If an atom is at rest relative to your reference frame, ie. the Earth in your post, then we will measure its length as being X. If it is moving relative to the Earth we will measure its length as Y. We measure the highest value for length when the atom is stationary, the lowest value for mass, and the lowest value for velocity (0). Velocity can't change without length/mass changing also.

 

[aura]

Length and mass are only constant if velocity is constant. If an atom is at rest relative to your reference frame, ie. the Earth in your post, then we will measure its length as being X. If it is moving relative to the Earth we will measure its length as Y. We measure the highest value for length when the atom is stationary, the lowest value for mass, and the lowest value for velocity (0). Velocity can't change without length/mass changing also.

Do you know that there is something called as " rest mass" which remains constant even if the particle moves and is the intrinsic property of the particle.As the numeric const of the size was compared with velocity, i gave this example.i already mentioned the word "stationary" while commenting on "mass" and a person who knows a bit of basic should know that it refers to the rest mass of the particle.Now the sentence"rest mass of a stationary atom" is meaningless at least to me.



I don't want to comment on other's concepts.They may go ahead.There is always a possibility that someone misses something while arguing and it's not unusual that someone missed to think about "rest mass"[that i was talking about] and i am not like a person who will infer from this, that the one doesn't know what is "rest mass" but i want people to admit when there is some reasonable matter and instead of crossing that, i want them to think about it and its not a debate so if they find my queries justified and if, ever they have also thought similarly, they can also give facts in favour of the matter.That will in no way harm anybody.I just don't like arguments which are forceful rather than convincing.Here we are not standing for or against the motion so there is no harm to support any perspective and to try to find the reason. I think this is enough.

ps- i will not answer anymore and since i am a bit busy will not be able to visit either.

bye

 

[Kazza_765]

Do you know that there is something called as " rest mass" which remains constant even if the particle moves and is the intrinsic property of the particle.As the numeric const of the size was compared with velocity, i gave this example.i already mentioned the word "stationery" while commenting on "mass" and a person who knows a bit of basic should know that it refers to the rest mass of the particle now the sentence"rest mass of a stationery atom" is meaningless at least to me.

Why would I mention that mass is at a minimum when stationary in your reference frame if I didn't know there is a rest mass. You don't seem to be making any sense.

say Earth (as an isolated system) in that ref frame when we measure size of a stationary atom, it remains same but speed need not be if its moving

I think this is where your problem lies. If an atom is stationary it has a measurable size and velocity, which remain constant. From what I can tell you go on to say that in our reference frame - Earth - a stationary atom has a constant mass/size but a variable velocity.

but remember that vel can be variable even in the ref frame where the length is not

If the velocity of the atom changes it is no longer stationary. You are correct in that the mass/size of an atom stationary in our reference frame is constant, but so is its velocity. Its when you change the speed of the atom relative to you, that you also change its size. You can't change one without the other, either it is stationary and mass/size/velocity is constant, or it is moving relative and mass/size/velocity are transformed.

 

[aura]

If the velocity of the atom changes it is no longer stationary. You are correct in that the mass/size of an atom stationary in our reference frame is constant, but so is its velocity. Its when you change the speed of the atom relative to you, that you also change its size. You can't change one without the other, either it is stationary and mass/size/velocity is constant, or it is moving relative and mass/size/velocity are transformed.

rest mass remains const even if the atom moves! even if vel during its motion changes!...Mo remains const so does Lo

M=Mo/sqrt(1-vsqr/csqr)

Mo always remain const irrespective of whether the particle moves or not...its M that changes but i am talking about Mo..vel is not any intrinsic property as the rest mass, it changes when the atom moves[say initially it was 0 while at rest and while in motion its x m/s but Mo will be Mo both when the atom is at rest and is in motion, only what changes is M but i am talking of Mo(rest mass)].Now please i think this is going too far and i am getting tired of explaining ..don't make me answer again and again...its a request...

thanks

 

[Doc Al]

I think this thread has gone on long enough.