Suppose the Light Speed was just 330 [m/sec];-)

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t00fri
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Suppose the Light Speed was just 330 [m/sec];-)

Post #1by t00fri » 25.06.2003, 16:10

What does everyone think how our world and everyday's life would look like, if the speed of light was really slow, say around 330 [m/sec], the speed of sound in air?

Could we exist at all?;-)

Bye bye Fridger

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Post #2by ElPelado » 25.06.2003, 16:19

Could we exist at all?;-)


why not?i am asking seriously, i mean: if that were the light speed, would it change something in our lifes?
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Post #3by Borg Collective » 25.06.2003, 16:22

Well, you would have a "very fast" travelling aeroplanes, invisible to the eye.
What am I doing? Ah, nothing much. Just laying on my bed, watching the stars, and sky, and keep asking myself: 'Where the Hell is my Roof?'.

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Post #4by timcrews » 25.06.2003, 16:49

Would the other laws of physics still apply in this hypothetical universe? Most of my ideas involve the interaction of the rest of the known universal constants with this changed constant value for the speed of light.

Most importantly, if faster-than-light motion is disallowed, then our solar system could not exist as we now know it. I haven't worked out the specific numbers, but don't we have many planets whose surfaces are rotating at faster than this proposed "speed of light"? Maybe I'm wrong about that, but _definitely_ the planets are currently orbiting the sun at faster than 330 m/sec.

Also, if relatavistic effects kicked in as this "speed of light" was approached, then I guess some pretty weird stuff would be happening on the Autobahn. College students would be hopping in souped-up minivans and driving at "1/4 the speed of light" to get extra time to do their homework.

If the gravitational constant continues to be the same in this hypothetical universe, wouldn't we end up with a lot of black holes? For example, minus other opposing forces, earth's gravitational acceleration of 9.8 m/s2 would only require a half a minute of acceleration to achieve this new speed of light.

The advantage of fiber optic networks would be nullified. Electrical signals already travel much faster than this new "speed of light".

If the speed of light and the speed of sound were identical, then there would be no delay between lightning and thunder.

My examples are becoming less creative now.

Tim

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Post #5by julesstoop » 25.06.2003, 17:05

No, there would just be a huge red shift when it is moving away from you, and a similarly huge blue shift in de opposit situation. Due to relativistic effects, nothing would be able to much faster than about some 500 miles/hour due to the tremendous amount of energy involved of accelerating to even faster speeds.

The solar system (let alone most of the rest of the universe) wouldn't be able to exist. For the sake of the argument, if it could, fotons from the sun would take some 14 years to reach the surface of our planet.

OTH: In a lightspeed == 330 m/s - unverse, with similarly built laws of physics everything (including al chemical processes in your body) would be much slower, because c is a universal constant the laws of physics depend upon it. So it that way you wouldn't notice any difference yourself, only when looking upon it from a different viewpoint. It probably would look pretty similar to a system you are moving away from (in our universe) @ a speed close to 'normal' c.

If we would be able to impose this change to our present universe, al stable systems would have to be a lot slower (colder) but this is of course impossible.
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Post #6by t00fri » 25.06.2003, 17:11

Right Tim & Julesstoop,

I think you are 'driving' into the right direction for this subject. It might just start up for some with a simple : What should be all that different? (<= ElPelado) to more and more weired consequences, one will inevitably encounter after just a little bit of contemplation of this "Gedankenexperiment";-).

Bye Fridger

GBrown

Post #7by GBrown » 25.06.2003, 17:34

My guess would be that everything would be smaller, since information propagation (bounded by the speed of light) would be a heck of a lot slower.

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Post #8by Evil Dr Ganymede » 25.06.2003, 18:41

Carl Sagan showed something like this in the Cosmos series, with a kid on a motorbike (though he set the speed of light to 40 mph). I forget which episode, it was somewhere in the middle of the series.

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Post #9by Christophe » 25.06.2003, 19:47

julesstoop wrote:The solar system (let alone most of the rest of the universe) wouldn't be able to exist.


Why? Can't we have stable relativistic orbits?
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Post #10by granthutchison » 25.06.2003, 20:17

Christophe wrote:Why? Can't we have stable relativistic orbits?
None of the planets could have stable orbits, because all of them would need to move faster than light - that would pertain all the way out to about 10000AU.
So it's difficult to see how "useful" stars would form, since by the time they were massive enough to generate light and heat, their escape velocity would be greater than the speed of light - they would be black holes.
There's also the problem of nucleosynthesis - even if we assume that heavier elements were produced normally in first-generation stars, brewing away inside their monstrous event horizons, those elements could never be ejected by supernovae to form the basis for planets and carbon-based life-forms (as they say in Star Trek :wink:). No material could be blown free in a supernova explosion, because it would have to move faster than the speed of light in order to escape the parent star. So the Universe, I guess, would consist of a large number of black holes and a thin wisp of hydrogen - no planets, no humans.
(Assuming the Big Bang could even get underway given Fridger's constraint - but that is very definitely Fridger's territory ...)

Grant
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Post #11by t00fri » 25.06.2003, 20:21

Christophe wrote:
julesstoop wrote:The solar system (let alone most of the rest of the universe) wouldn't be able to exist.

Why? Can't we have stable relativistic orbits?


Of course;-), otherwise I would be jobless...

But clearly those orbits would be /markedly/ different in size, since the maximum speed is that of sound;-). Let's think a moment about the size of the orbit of the earth, for example...with the sun's mass being the same as always...




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Post #12by Christophe » 25.06.2003, 20:45

t00fri wrote:But clearly those orbits would be /markedly/ different in size, since the maximum speed is that of sound;-). Let's think a moment about the size of the orbit of the earth, for example...with the sun's mass being the same as always...


Doesn't inertia increase when the velocity gets close to c? Couldn't you have a stable orbit of the same size by adjusting the velocity?

And wouldn't the Sun be a black hole? And all the planets too?
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Post #13by t00fri » 25.06.2003, 20:57

Christophe wrote:
t00fri wrote:But clearly those orbits would be /markedly/ different in size, since the maximum speed is that of sound;-). Let's think a moment about the size of the orbit of the earth, for example...with the sun's mass being the same as always...

Doesn't inertia increase when the velocity gets close to c? Couldn't you have a stable orbit of the same size by adjusting the velocity?

Honestly, I do not know off hand, but if true, it would be very remarkable!

And wouldn't the Sun be a black hole? And all the planets too?


Now I am getting more than childish: I think God must have been a physicist to avoid all such horrors;-)

Bye Fridger;-)
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Post #14by Christophe » 25.06.2003, 21:06

t00fri wrote:Now I am getting more than childish: I think God must have been a physiscist to avoid all such horrors;-)


And a pretty clever one too! Now what is c was a lot greater, like 1 ly/s? We'd have really fast computers, instant communication across the solar system... and no LT code in Celestia ;-)
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Post #15by t00fri » 25.06.2003, 21:18

Christophe wrote:
t00fri wrote:Now I am getting more than childish: I think God must have been a physiscist to avoid all such horrors;-)

And a pretty clever one too! Now what is c was a lot greater, like 1 ly/s? We'd have really fast computers, instant communication across the solar system

Yes that variant is also interesting to contemplate...

... and no LT code in Celestia ;-)


h? h?...it seems you are now getting childish, too (un bon verre du rouge ?;-))

Bye Fridger

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Post #16by julesstoop » 26.06.2003, 00:18

Quelques bouteilles du vin rouge, peut-?tre?

However,

Maybe we should try to consider the evolution of an universe which big-banged with this extremely low c. In this universe everything still existing after some 13 billion years would be contained in very cold and slow, mostly very small, systems. I'd be suprised if any form of life would have been able to evolve in - considering this particular universe - this relatively short period of time.
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Post #17by jrobert » 26.06.2003, 03:08

Christophe wrote:Now what is c was a lot greater, like 1 ly/s? We'd have really fast computers, instant communication across the solar system... and no LT code in Celestia ;-)


Well, lets consider this: one actual light year is equal to 5.878612843 E 12 statue miles. Thats under the rule that c = 186282 miles/sec. If we use Christophe's speed of light constant, then c = 5.878612843 E 12 miles/sec. There'd be no black holes and we'd be able to use telescopes to see "before" the big bang (if there even is a "before") :wink:

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Post #18by Paul » 26.06.2003, 03:17

In this universe everything still existing after some 13 billion years would be contained in very cold and slow, mostly very small, systems.


I don't think they would be very small - quite the opposite. In fact, about as opposite as you can get - the whole Universe would be a handful of gigantic black holes (or possibly even just one)!

If two very massive objects orbit each other at "close to" c, they emit gravitational waves (i.e. energy) and thus their orbits decay. The end result is that they merge. The lower the value of c, then, the more orbits decay and masses merge. For a value of c that low, then, I would expect so few orbits to persist that almost all matter in the Universe will have merged together, and almost all (non-matter) energy will consist of a turbulent sea of gravitational waves. Whether this would be "very cold" is also doubtful, but then I don't know enough about gravitational waves and their effect on the temperature of matter.

Cheers,
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Post #19by julesstoop » 26.06.2003, 22:44

[Yoda mode]
Atoms, molecules, all fundamental building blocks sort of shake constantly, at pretty high speeds (for instance: electrons orbiting). The more erratic this background noise of everything moving in a certain object, the hotter the object in question. These motions are bound by the speed of light as well, so: The lower the speed of light -> the slower everything theoretically can move -> the colder the universe will be
[/Yoda mode]

There is no reason to suppose that more black-holes would exist. The gravitational constant would be proportionally smaller when the speed of light were to be as small as suggested. So we would still need enormous concentrations of matter to build a black hole.

We would simply have a smaller and much colder universe. The problem would be: if atoms still have the same size as they have now, building complex (life) molecules would probably be impossible. If the atoms are shrinked down as well, the universe would be just the same as ours, only everything woould happen at a smaller scale and lower temperature. The difference would only be - as I said before - noticable to someone observing the universe from a location within our 'normal' universe.
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Post #20by granthutchison » 27.06.2003, 00:09

julesstoop wrote:The lower the speed of light -> the slower everything theoretically can move -> the colder the universe will be
But temperature is a measure of the mean kinetic energy of molecules, not their velocity. And since mass increases as light-speed is approached, the kinetic energy can still rise without limit - so there would be no limit to temperature in the way you describe.

julesstoop wrote:The gravitational constant would be proportionally smaller when the speed of light were to be as small as suggested.
I don't see how the one implies the other. In my reading G and c are described as being entirely independent, equally fundamental constants. Why should they influence each other?

Grant


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