Setting the Cosmic Speed Limit

Darth Raptor · Post by **Darth Raptor** » 2008-02-17 09:09am

A question for those better educated than I: What would happen if the speed of light were universally "adjusted" upwards ala Futurama? Or imagine a universe where c is an arbitrary value much higher than it is in ours. While this would most certainly facilitate travel without any messy causality issues, I suspect it would have all sorts of far-reaching, unintended consequences. My (woefully limited) understanding is that the speed of light is Very Important for how everything in the universe operates; from large-scale physics to chemistry right down to quantum mechanics. Would such a world even be livable? What about one with a significantly lower speed limit?

Brimstone · Post by **Brimstone** » 2008-02-17 10:03am

I don't think it is possible to change the speed of light, since it would be like trying to change the momentum of a ball without changing its velocity or its mass.

What you can do is change the properties of matter. If the elementary charge is different, or the mass of an electron is different, huge changes can result. To effectively change the speed of light, you change the properties of matter so that physical processes proceed slower or faster. Slower physical processes mean a greater speed of light in relation. Of course, this by definition would have no effect other than changing the (perceived) speed of light. Changing the properties of matter in different ways can have many other interesting and disastrous effects, of course.

Steel · Post by **Steel** » 2008-02-17 10:41am

Seeing as c pops out of maxwells equations as a constant, changing c would likely destroy all current forms of life at the least, and would be capable of totally changing the structure of the universe. (Maxwells equations govern electormagnetism, and are also derivable from higher structures)

CmdrWilkens · Post by **CmdrWilkens** » 2008-02-17 02:07pm

Steel wrote:Seeing as c pops out of maxwells equations as a constant, changing c would likely destroy all current forms of life at the least, and would be capable of totally changing the structure of the universe. (Maxwells equations govern electormagnetism, and are also derivable from higher structures)

The problem here is that Maxwell's equations DESCRIBE nature. They do not CONTROL nature. if the speed of light were to shift, or begin to shift right at this moment (for reasons unknown to us obviously) we would be looking at huge changes almost instantly. For starters we would either have to eliminate mass from the universe or somehow work around the 2nd law of thermodynamics because the increase in the speed of light would have an immediate increase in the available energy of the universe. Alternatively we could immediately assume that the unvierse is not a closed system which opens up all sorts of possibilities. Anyway that's my immediate two cents of thought but I can guess quickly that the consequences would touch literally EVERYTHING in existence.

Molyneux · Post by **Molyneux** » 2008-02-17 02:32pm

CmdrWilkens wrote:
Steel wrote:Seeing as c pops out of maxwells equations as a constant, changing c would likely destroy all current forms of life at the least, and would be capable of totally changing the structure of the universe. (Maxwells equations govern electormagnetism, and are also derivable from higher structures)
The problem here is that Maxwell's equations DESCRIBE nature. They do not CONTROL nature. if the speed of light were to shift, or begin to shift right at this moment (for reasons unknown to us obviously) we would be looking at huge changes almost instantly. For starters we would either have to eliminate mass from the universe or somehow work around the 2nd law of thermodynamics because the increase in the speed of light would have an immediate increase in the available energy of the universe. Alternatively we could immediately assume that the unvierse is not a closed system which opens up all sorts of possibilities. Anyway that's my immediate two cents of thought but I can guess quickly that the consequences would touch literally EVERYTHING in existence.

What I'd like to know is: could a universe with a substantially higher value of c harbor anything resembling our organic life?

Gullible Jones · Post by **Gullible Jones** » 2008-02-17 07:50pm

The fine structure constant would change, and we'd probably all die fast and horrible deaths.

Post by **Surlethe** » 2008-02-17 08:44pm

CmdrWilkens wrote:
Steel wrote:Seeing as c pops out of maxwells equations as a constant, changing c would likely destroy all current forms of life at the least, and would be capable of totally changing the structure of the universe. (Maxwells equations govern electormagnetism, and are also derivable from higher structures)
The problem here is that Maxwell's equations DESCRIBE nature. They do not CONTROL nature.

It is true that Maxwell's equations describe nature and do not control it. So if we assume that Maxwell's equations are an accurate description, we can see what will happen to EM if c shifts. For example, in addition to the cons. of energy implications you noted, because k = 1/(4πε_0) and ε_0 = 1/(μ_0c^2), we have k = (μ_0c^2)/(4π). So the value of Coulomb's constant will increase with the square of the increase in c, which has major implications for, say, the value of the electric force, the energy density of electric fields, and probably the stability of atoms.

wjs7744 · Post by **wjs7744** » 2008-02-17 09:58pm

It's pretty much a given that changing universal constants like c would likely destroy all life in the universe, but as to the question of whether if the universe had always had a different value life would have been possible seems pretty much unanswerable to me. After all, life as we know it adapted to the universe, there is no evidence that the universe had to be preadapted for life to exist at all.

Junghalli · Post by **Junghalli** » 2008-02-17 11:04pm

The question of what stepping into a realm with alternate laws of physics will do to you is always the niggling unasked question of FTL methods that involve going into some kind of "hyperspace".

It'd really suck if we found a way to access a realm where c was 100,000 times what it was in our universe and there was a 1:1 correlation between locations there and locations here but, say, in that same realm electromagnetism was as weak as gravity so anything you sent into it would disappear into a puff of monoatomic gas.

Winston Blake · Post by **Winston Blake** » 2008-02-17 11:47pm

The only way I could see this working is if the known speed of light was some kind of false limit. 'Something' is retarding all interactions in the universe, and by locally removing that 'something', you can go faster than 'false c' (and probably kill yourself). Anyway, 'real c' is (and always has been) the true relativistic maximum, but it only becomes observable under extraordinary conditions.

Does anyone know if this is plausible?

CmdrWilkens · Post by **CmdrWilkens** » 2008-02-18 07:34pm

On the larger question of whether life would evolve in any format I think itsclose to impossible to say. At the very least the fundamental changes would mean that the balance between the strong, weak, gravitational, and electromagnetic forces which enables atoms as we know them to form would be thrown out of whack. Now whether "life" could arise with completely different atomic structures I don't know but it would bear little to no resemblence to life as we know it.

Keevan_Colton · Post by **Keevan_Colton** » 2008-02-18 08:18pm

Winston Blake wrote:The only way I could see this working is if the known speed of light was some kind of false limit. 'Something' is retarding all interactions in the universe, and by locally removing that 'something', you can go faster than 'false c' (and probably kill yourself). Anyway, 'real c' is (and always has been) the true relativistic maximum, but it only becomes observable under extraordinary conditions.

Does anyone know if this is plausible?

What you want is the aether, light travels at different speeds in different materials...there was once the notion of an aether that light traveled through and relative to. Since it did nothing else really and was basically unnecessary we chucked it and just consider the speed of light in a vacuum.

Steel · Post by **Steel** » 2008-02-19 04:48am

Keevan_Colton wrote:
Winston Blake wrote:The only way I could see this working is if the known speed of light was some kind of false limit. 'Something' is retarding all interactions in the universe, and by locally removing that 'something', you can go faster than 'false c' (and probably kill yourself). Anyway, 'real c' is (and always has been) the true relativistic maximum, but it only becomes observable under extraordinary conditions.

Does anyone know if this is plausible?
What you want is the aether, light travels at different speeds in different materials...there was once the notion of an aether that light traveled through and relative to. Since it did nothing else really and was basically unnecessary we chucked it and just consider the speed of light in a vacuum.

Not quite, the aether was the notion of an absolute frame of reference. Light propagated at c through the aether, and then all the relative velocity laws that we knew would hold relative to the aether. This was confusing as c popped out of the maxwell equations without considering any frame of reference, so people assumed that meant that maxwells eqns were true in the frame of the aether.

The notion of an absolute frame of reference was disproved in an experiment by Michelson and Morley, so along with that people ditched aether.

Winston Blake · Post by **Winston Blake** » 2008-02-19 08:33pm

Keevan_Colton wrote:What you want is the aether, light travels at different speeds in different materials...there was once the notion of an aether that light traveled through and relative to. Since it did nothing else really and was basically unnecessary we chucked it and just consider the speed of light in a vacuum.

No, I mean a universe where relativity still holds and everything, it's just that light 'actually' propagates at, say, 1000c. This universe has developed under 'retarded' conditions from the start, so FTL up to 1000c is possible because you're not exceeding the 'true' speed of light. I doubt vehicles would be possible, but FTL communications might be.

CmdrWilkens · Post by **CmdrWilkens** » 2008-02-20 12:57am

Winston Blake wrote:
Keevan_Colton wrote:What you want is the aether, light travels at different speeds in different materials...there was once the notion of an aether that light traveled through and relative to. Since it did nothing else really and was basically unnecessary we chucked it and just consider the speed of light in a vacuum.
No, I mean a universe where relativity still holds and everything, it's just that light 'actually' propagates at, say, 1000c. This universe has developed under 'retarded' conditions from the start, so FTL up to 1000c is possible because you're not exceeding the 'true' speed of light. I doubt vehicles would be possible, but FTL communications might be.

Then you are looking for something very akin to the orginial idea of "aether" nto just as a fixed point of reference but as a medium through which light moves at the given observed speed of 'c'. At the saem time it would need to be so perfectly uniform as to not intrude upon any calculation which would show 'c' as we measure it being the value presently assigned. That's a pretty tall order.