speed of light

[Guest mikaela]

hi! i came across this questionin class and to tell you honestly, i have no idea as to the answer to the question.. so i badly need your help.... thanks a lot!

 

here it goes:

 

What do you think would be different in everyday life if the speed of light were 10 m/s instead of its actual value?

[swansont]

Nothing would go faster than 10 m/s.

[ydoaPs]

very confusing. time would be all wacky and so would distance.

 

t'=t/[sqrt{1-(v^2)/(c^2)}]

 

d'=d*sqrt{1-(v^2)/(c^2)}

 

it would be easier to read if latex was working.

[Martin]

hi! i came across this questionin class and to tell you honestly' date=' i have no idea as to the answer to the question.. so i badly need your help.... thanks a lot!

 

here it goes:

 

What do you think would be different in everyday life if the speed of light were 10 m/s instead of its actual value?[/quote']

 

you could not change our psychological experience of the speed of light because if you could "slow light down" in its progress, say, across the street this would also slow down the electrical and chemical processes in your brain

 

so it would still seem to take a very short time for a flash of light to go across the street

 

the biological and psychological experience of time is so geared to c, that there is no way to change c so as to change our experience of the world

 

your body and brain are synched to c. it is difficult to attribute meaning to "slowing light down" in the sense of reducing c across the board.

 

slowing one particular pulse of light down is a different matter, I mean not changing c (the universal constant that is at work in all things) but just changing the speed of some particular pulse or flash of light in some medium in some laboratory. that is different but I dont think it is what you meant.

 

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the standard model of physics has a couple dozen dimensionless constants. they are pure numbers. a prime example would be e.g. the ratio of the mass of a certain quark to the natural mass unit.

 

(the natural mass units assume G = hbar = c = 1)

 

if you could modify any one of these dimensionless constants, then by doing that

you could change nature and life, the periodic table of elements, the nuclear reactions inside stars, etc etc,

 

but c, or the "speed of light in vacuum" is not a dimensionless constant, it is the unit speed of the standard model.

 

the standard model is like a box with a couple dozen knobs that you can imagine turning and making the universe and our experience of it very different, even weird, or impossible

 

but there is no knob on the box labeled "speed of light"

 

maybe you should change your question and ask what would happen if one were to change alpha (the finestructure constant) by some amount.

that is a welldefined question, there is a conceptual knob on the model, it could make things very weird or even destroy the universe as we know it.

 

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there is another quite different way to respond to your question.

At the present time according to human laws, the speed c is actually not a measured quantity but is established by convention

 

it would not make sense to claim that one had measured the speed of light and gotten a different answer from 299792458 meters per second.

 

If one were to say "I measured it in my laboratory and c equals

299792458.17 meters per second" that would be a meaningless statement. Because given the way that the METER is now defined it is legally only possible for c to be equal to PRECISELY 299792458 meters per second.

It cannot, for example, be 299792457.99993

 

 

in the official metric system (governed by international organizations empowered by treaty) the meter is defined as the distance light in vacuum travels in 1/299792458 of a second. that means that the speed of light is established by human law (as 299792458 meters per second) and not by nature. with our present system, we can change the speed of light merely by a stroke of the pen, by changing the law. And only in this way can it be changed (since it is an arbitrary human convention.)

 

Logically, what you are asking about is equivalent to redefining the meter as the distance light in vacuum travels in 1/10 of a second.

 

this would make the meter longer but would have no physical effect on everyday life, or nature and the universe. It would just affect the metric system by changing one of its units and whatever depends on that arbitrary choice.

 

we would just have a big load of paperwork to do, changing all the numbers of meters listed in handbooks, schoolbooks, records, blueprints and documents