Why light speed

[dasraiser]

hi everyone im a newbe and admit i dont know much science (but im learning), my problem is why is light speed so important? if our eyes worked at some other freq other than light would everyone be going on about say the speed of gama-rays etc, also does the em spectrum operate on a carry wave?

as for things travelling faster than light, a good experiment might be to take a solid rod 1 light year in length (or an achieveable length) and then push one end of it and time how long it would take for the other end to move, sort of the speed of light vs kinetic energy transferrence.

[Qfwfq]

Welcome dasraiser.

hi everyone im a newbe and admit i dont know much science (but im learning)

This can be a good place to learn a few things. :hihi: Ask questions and you usually get answers. Perhaps even more than one, with some answers contradicting others! :hyper:

 

why is light speed so important? if our eyes worked at some other freq other than light would everyone be going on about say the speed of gama-rays etc, also does the em spectrum operate on a carry wave?

The speed of gama-rays is the same as that of light, in the vacuum.

 

What is important isn't so much the speed of light but c, it's just that c is very often called "the speed of light" for historic reasons. In the vacuum, any massless particle is doomed to travel at c and can't help but travelling at c. The fundamental reason is that space-time has this structure and it is a now well verified fact of reality. Strictly, c = 1. If you measure it in km per second or in miles per second you are really just comparing different units of "length" because a second is the same "length" as 300,000 km or 186,000 miles. There isn't all that much difference between space and time, they are but different directions in space-time.

 

as for things travelling faster than light, a good experiment might be to take a solid rod 1 light year in length (or an achieveable length) and then push one end of it and time how long it would take for the other end to move, sort of the speed of light vs kinetic energy transferrence.

This idea has already appeared on these boards, the first time was here:

 

http://hypography.com/forums/showpost.php?p=26859&postcount=24

 

and later here:

 

http://hypography.com/forums/showthread.php?t=2294

[rockytriton]

I have an iron rod that's 1 light year in length, if anyone wants to borrow it for this experiment, just let me know! :hyper:

[Tormod]

also does the em spectrum operate on a carry wave?

 

All the waves in the EM spectrum travel at the same speeds. And no, there is no carrier wave.

[UncleAl]

why is light speed so important?

Annalen der Physik 4 XVII 891-921 (1905)

Annalen der Physik 4 XLIX 769-822 (1916)

 

Lightspeed, c, enforces maximum information transfer rate. Newton's constant, Big G, scales gravitation. Planck's constant, h, enforces uncertainty in measurement; h-bar is the fundamental unit of action. Taken together they define all of physics.

 

h=0 G=G c=c: general relativity

h=h G=0 c=c: quantum field theory

 

No predictive mathematical model of reality assigns all three constants their empirical values. Feel free to create one.

[dasraiser]

Hi, thank you for responses. I shell do a search next time before posting. :hyper:

 

I found the postings an interesting read, if the rod has a mass then kinetic wave energy will move the other end, but lower than c, and if it is completely massless it will move at or around c, but I find this is confusing, mainly down to wave energy traveling faster through a medium and with space being a vacuum makes this out to be a contradiction. :) that is if i understood the postings. :hihi:

 

MMM finding a value to scale all theories correctly without a starting reference might be a bit tricky, but if I find one UncleAl, I'll let you know :)

 

now on to much learning.

[GreekTTC]

I have an iron rod that's 1 light year in length, if anyone wants to borrow it for this experiment, just let me know! :hyper:

 

What would shipping charges be on something like that? :hihi:

[UncleAl]

[qoute]if the rod has a mass then kinetic wave energy will move the other end, but lower than c, and if it is completely massless it will move at or around c, but I find this is confusing, mainly down to wave energy traveling faster through a medium and with space being a vacuum makes this out to be a contradiction.

Physical disturbances travel at the speed of sound in a medium. Shocks travel faster, but rapidly decay into sonic displacements. If you had a massless rod, how would it be it stiff? For that matter, what are the three kinds of sonic disturbances posssible in a solid? The one in a fluid?

 

All this crap has been repeated debated ad nauseam in Usenet. Google Groups. The whole idea of written language - and search indices - is that knowledge accumulates while stupidity dissipates. American zero-goal education (every child left behind) has put the broken cart before the dead horse.

[dasraiser]

UncleAl

"American zero-goal education (every child left behind) has put the broken cart before the dead horse"

yeah cool but im a brit :hyper: :hihi:

 

UncleAl

"Shocks travel faster, but rapidly decay into sonic displacements"

 

cool i can relate, the energy cannot be sustained unless otherwise acted upon

 

still reading still trying to learn... ok told u im a beginner, and found an even more disturbing link at the bottom of the page about sr for beginners all bit distracting.

[Qfwfq]

All this crap has been repeated debated ad nauseam in Usenet. Google Groups. The whole idea of written language - and search indices - is that knowledge accumulates while stupidity dissipates. American zero-goal education (every child left behind) has put the broken cart before the dead horse.

Don't start getting back to old habits Uncle Al.

[Qfwfq]

mainly down to wave energy traveling faster through a medium and with space being a vacuum makes this out to be a contradiction.

I'm not sure where you see the contradiction. ?

 

The propagation through the material will never be faster than c, it will always be substantially less as it also involves motion of the constituent particles which is communicated between them by the fields.

[EWright]

What about a stiff rod made entirely of light: ie, a giant light saber! :surprise:

[dasraiser]

ok the confusion is all mine, i based the universe rather naively on the model of sound, for a brief moment jumping in with both feet before realizing the errors of my ways :surprise: .

(isn't there something about reading your post twice before committing it for the world to see, or am i thinking of something else :surprise: )

 

eWright

"What about a stiff rod made entirely of light: ie, a giant light saber! :confused: "

 

mmm maybe from the frame of light the action will happen instantaneously ,but as observers we'll probably see it move in one year (but i guess from any frame it would still move c),It would certainty help the jedi, imagine the sound it would make cool :shrug:

[Qfwfq]

Hmmm, imagine you're on a spaceship, so you don't need to bother about Earth's motion, and you shine a laser in the direction of one star. After one year of continuous laser output, you turn the box to point in the direction of another star.

 

What happens to the beam when you turn the box?

[dasraiser]

hi Qfwfq, assuming the box is the laser (and this is not a trick question), the last photon out of the box before it turns will carry on to the 1'st star followed by many other beams of light(photons) that stream of into space until they interact with something (refract/reflect/bend by gravity/etc) in the direction they were released from the box, unlike the light saber which somehow holds the photons in a force field; static or like a laser bouncing them up and down it's length.

 

ok my level of understanding is albeit theoretical/conjecture with not much in the way of math, but trying to google search this subject is somewhat daunting and finding a good mathematical starting point is in essence, eluding me. However i am making small progress and would welcome any places or further subjects you could recommend for study.

 

My main problem is, theories remain until the all facts are known.

 

I have many questions, but before i post again i will try to find the answers for my self, asking grand question with a possible answer(self verification)(which i was going to do here) will be unproductive as i would probably not understand the answer given(not much conservation of energy there :surprise: ) an example

 

Uncel Al

h=0 G=G c=c: general relativity

h=h G=0 c=c: quantum field theory

 

ehh? :confused: , i will find the answers and hopefully the understandings will follow.

 

looking forward to your help.

[paultrr]

ok the confusion is all mine, i based the universe rather naively on the model of sound, for a brief moment jumping in with both feet before realizing the errors of my ways :surprise: .

(isn't there something about reading your post twice before committing it for the world to see, or am i thinking of something else :surprise: )

 

[

 

Yes, sounded like a commercial for older ather theory to me also. But I did see the point you where trying to get across.

[paultrr]

Hmmm, imagine you're on a spaceship, so you don't need to bother about Earth's motion, and you shine a laser in the direction of one star. After one year of continuous laser output, you turn the box to point in the direction of another star.

 

What happens to the beam when you turn the box?

One of the oldest known seemingly FTL effects. However, while the whole beam sweeps across an expanse of the universe FTL could, the individual photons never exceed such.