What If the Speed of Light Were Just 1000 km/h?

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Discussion Overview

The discussion explores the hypothetical scenario of the speed of light being 1000 km/h (278 m/s) instead of its actual value. Participants consider the implications of this change on various aspects of the universe, including the formation of galaxies, the behavior of chemical reactions, and the nature of physical laws. The conversation is divided into two scenarios: one where this change occurs at the beginning of the universe and another where it happens in the present day.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • Some participants suggest that if the speed of light were 1000 km/h, the universe's expansion and the formation of galaxies, stars, and planets would be significantly affected, leading to complex consequences.
  • Others argue that if this change occurred now, it could lead to catastrophic effects on chemical reactions and everyday physics, potentially resulting in the extinction of life on Earth.
  • A participant points out that the assumption of all other fundamental constants remaining unchanged is logically contradictory, as changes in the speed of light would necessitate adjustments in other constants to maintain physical consistency.
  • Another participant introduces the idea of a multiverse, suggesting that a universe with such a low speed of light would not be viable, as it would lead to scenarios that are not physically possible.
  • One participant humorously suggests a programming analogy to illustrate the absurdity of the scenario, indicating a playful approach to the discussion.

Areas of Agreement / Disagreement

Participants express a range of views, with some agreeing on the catastrophic implications of a lower speed of light, while others challenge the feasibility of the scenario itself. There is no consensus on the outcomes or implications of this hypothetical situation.

Contextual Notes

Participants highlight the complexity of the scenario, noting that many questions raised are not easily answerable due to the far-reaching effects of such a fundamental change in physical constants.

Numeriprimi
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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 :-)
 
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Numeriprimi said:
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?

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.
 
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 fundamental constants, available here

www.arvindguptatoys.com/arvindgupta/tompkins.pdf
 
Numeriprimi said:
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.
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
 
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:
Let's try it and see what happens, shall we?

Code: 
//#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.
 
Numeriprimi said:
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.
? The speed of sound in a vacuum is 0!

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 :-)
 
Oh, I know... Sorry. I thought air.
 

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