# If c = 1000 km per hour

1. Sep 29, 2013

### Numeriprimi

I'm thinking about speed the speed of light. It is really interesting constant. What would the world (if it ever was), if this value was different? :-) In the microworld, macroworld, in the life of humans, animals and plants ...
Ok, I say the c = 1000 kilometer per hour = 278 meters per second. That's a big difference :-)
AND - all the other fundamental constants stayed unchanged. What now?

Divide it into two options - A) if it happens at the beginning of the world and B) if that happened NOW.
It is very complidated question for me. Can you help me how can I imagine this world?

A) Hmmmm... It is very complidated question for me. The universe may expand even faster than C. This is not a problem. But the formation of the galaxies, stars, planets? Some of them move faster. They could not reach C. Disintegrated of the cluster? And what partiples? I really do not know. Can you help me?

B) The speed of sound in a vacuum is higher than C - can not be spread. And ultrasound, infrasound, gamma radiation, ultraviolet radiation, and other electromagnetic radiation? Movement of supersonic aircraft or trips into space is not possible. People can not understand the time - dilation is evident, adding speed is not apparent, length contraction too. Even at quite slow speeds ages more slowly. What next?

I'm very grateful for posts!!!
And sorry for my bad English :-)

2. Sep 29, 2013

### Staff: Mentor

If it happened now? Everything on earth would die horribly as relativistic effects completely screw with chemical reactions and everyday physics. If it was always like this life, if it existed, would be VERY different.

Most of your questions are simply not answerable as the effects of a having c suddenly change by such an extreme amount are so wide reaching that literally EVERYTHING is different.

3. Sep 29, 2013

### Mentz114

This scenario would be difficult to work to work out in full. The nearest thing I know of is a book by George Gamow which pictures a universe with different fundemental constants, available here

www.arvindguptatoys.com/arvindgupta/tompkins.pdf

4. Sep 29, 2013

### Staff: Mentor

This is a logical self contradiction, it is not possible. Consider the fine structure constant $\alpha = \frac{e^2}{2\epsilon_0 h c}$. If c changes then some other constant in this equation must also change.

It turns out that if the dimensionful constants change in such a way that the dimensionless constants remain constant then there will be no physically detectable difference. It is only if the combination of changes in dimensionful constants leads to a change in the dimensionless constants that there is a physically detectable difference. See:

https://www.physicsforums.com/showpost.php?p=2011753&postcount=55
https://www.physicsforums.com/showpost.php?p=2015734&postcount=68

5. Oct 2, 2013

### Noyhcat

I believe in the multiverse. So say there's a universe out there where the laws of physics are the same as ours except that c = .278 km/s instead of roughly 300,000 km/s.

If you suddenly transported there, you would surely die horribly, and as your screams would cause the air to hither to an fro at the speed of sound (340 m/sec), which I don't think would be possible because of c being 278 m/sec, maybe a black hole would form right at your lips and crush you immediately.

Yeah... it's not a possible scenario. There are versions of the universe that fail because they are not possible. Other constants would indeed have to change to keep the universe "alive".

You're basically asking what would a dead person say if you asked him what he wanted for lunch. He wouldn't say anything, because he can't. He's dead, just like the universe you're proposing would be.

-Noyhcat

Last edited: Oct 2, 2013
6. Oct 2, 2013

### BMW

Let's try it and see what happens, shall we?

Code (Text):

//#define SPEED_OF_LIGHT 300000000
#define SPEED_OF_LIGHT 278

I'll have to shut down the universe while I update the binaries, sorry for any inconvenience.

7. Oct 3, 2013

### HallsofIvy

Staff Emeritus
??? The speed of sound in a vacuum is 0!

8. Oct 11, 2013

### Numeriprimi

Oh, I know... Sorry. I thought air.

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