What if C didn't exist?

[WestAir]

What would the implications to both space travel and physics be if there were no speed of light? What if universal contraction, time dilation, and relativistic effects didn't exist? If light were literally instantaneous (The light from the stars of the Andromeda Galaxy took 0 seconds to reach Earth), if all reference frames saw all events occur at the same time (rather than being relative and separate), and if acceleration were perfectly linear (The energy required to accelerate from 0km/s to 10km/s were the same as the energy required to accelerate from 10km/s to 20km/s).

What would change for space flight?

For physics?

[jeti140973]

I think it would enable us to divide by zero, square the circle, double the cube, trisect the angle, and create perpetual motion

[keanukeno21]

i didn't understand what you just said... XD

[dustinsonger]

That's the point. What he is listing are things that are mathematically impossible. What he is saying is that if light moved instantaneously through space then everything would work differently and none of our mathematics or physics would work.

[lyndonguitar]

If there were no absolute c, we would still use classical physics, there would be no special relativity

[Merinsan]

If light traveled instantaneously, we would all be blind because of the extreme brightness of all the stars in the universe shining at us. Currently interstellar dust blocks some of that light, but instantaneous light travel would heat that dust to the point where it would glow, thus propagating the light. Come to think of it, the earth would glow too, meaning it'd be a ball of fire, and we wouldn't exist.

[K^2]

Things would be boring. For starters, it'd take absolutely forever to get anywhere. Without relativistic effects you could hope to cover what, a few hundred light years in human life time? With relativity, you can travel between galaxies. And I'm not even talkinga bout warp drive which could improve on that dramatically.

If light traveled instantaneously, we would all be blind because of the extreme brightness of all the stars in the universe shining at us.

That's a total non-sequitur. There is no correlation between speed of light and inverse R-squared law. It's the later and the fractal nature of the universe that prevent you from going blind.

[MennoLente]

K^2, there is no consensus about how to solve Olber's paradox. So Merinsan could be right. Well, at least if the size of the universe (with an (apparent) isotropic distribution of stars) would be large enough to create a uniform glow.

But if the speed of light would be infinite (or if it would have any other value that it has in this universe), it would create numbers of paradoxes. It might even cause the universe to collapse. Take for example the well known E=mc^2. If c would be infinite, than the energy released at the big bang would be infinite, and an infinite amount of matter would come to existance. Annihiliation would cause a infinite amount of energy to come to existance. Moreover, there would be no spacetime, so there would be no gravity.

Should I continue?

[K^2]

Can you cite me a single proposed resolution of Olber's paradox that breaks down under c -> inf?

[Michael Kim]

It will just be Newtonian. And space flights will actually be easier since accelerating will cost less energy. But there will be no warp drive though.

K^2, the observable universe is not the universe. Since there is light speed as the speed limit, anything outside the observable universe is meaningless to us (we cannot really tell if there is anything outside); but if there isn't that speed limit so we can instantaneously see everything.

While inverse R-squared law is correct, how much energy we receive per time has to do with how shiny matters are distributed. For an evenly distributed universe, the result goes with ln®, where r is the effective radius of the universe for Earth. Note that r means where the boundaries are. In our currently accepted model of universe (boundaryless but finite), it is infinite.

EDIT:

Can you cite me a single proposed resolution of Olber's paradox that breaks down under c -> inf?

Because we can only see things within the observable universe.

Edited May 28, 2013 by Michael Kim

[Holo]

Things would be boring. For starters, it'd take absolutely forever to get anywhere. Without relativistic effects you could hope to cover what, a few hundred light years in human life time? With relativity, you can travel between galaxies

But there's no maximum speed of light, so you could keep on accelerating forever. You can travel between galaxies. Even more, you can travel back home.

[Awaras]

If C was infinite there would be no redshift of light from distant stars, right? The sky would be a lot brighter then, I guess.

[Cesrate]

You CANNOT even think it of some kind of reality. You can only assume you're telling a fairy tale.

Because WHAT THE UNIVERSE BE IS WHAT THE REALITY BE. Maybe hard to understand...

All right, uhmm... You know, this is the fundamental rules of physics, which reflects "reality" called by some of us. The reality is reality. It is how we exist. If you wipe it out, we can only say...

You are trying to divide by zero or making 1+1=3.

[Holo]

You CANNOT even think it of some kind of reality. You can only assume you're telling a fairy tale.

Because WHAT THE UNIVERSE BE IS WHAT THE REALITY BE. Maybe hard to understand...

All right, uhmm... You know, this is the fundamental rules of physics, which reflects "reality" called by some of us. The reality is reality. It is how we exist. If you wipe it out, we can only say...

You are trying to divide by zero or making 1+1=3.

Well, yeah, that's why it's a hypothetical question, not a statement of fact. Learn to read, gosh

[K^2]

But there's no maximum speed of light, so you could keep on accelerating forever. You can travel between galaxies. Even more, you can travel back home.

I don't think you appreciate how long it would take to accelerate to any reasonable speed. At 1G it takes about a year to get up to speed of light. So if you plan to accelerate and then decelerate, it would take 20 years to cover just 100 light years. Maybe you can travel a little longer and accelerate a bit faster, but you'd still be confined to a few hundred light years. Maybe a few thousand if you push it to the limits.

Because we can only see things within the observable universe.

And given the divergence you get under assumption of uniform distribution, the observable universe is big enough to be "almost" infinite. Yes, the luminosity of the finite universe is going to be finite, but it still works out to be absurdly bright. It's not. It's pretty dark. So whatever the long distance behavior is, it's not divergent. And if it's not divergent, the actual size is irrelevant. With infinite c, you'd still get a convergent brightness.

[ZedNova]

Well, if light travelled instantly, i can tell you one thing. Space would look a whole lot more exciting than it already is.

[WestAir]

Earth might simply be destroyed. A Supernovae that launches protons and particles at us at what would have been relativistic speeds, but thanks to the lower energy requirements (linear acceleration) is now traveling hundreds of millions of kilometers per second faster than C would hit the Earth. The molecules in the atmosphere wouldn't have time to get out of the way of these faster-than-c particles and would fuse with the atoms and particles from the super nova, each collision releasing huge bursts of gamma rays and even more post-luminal scattered particles. Those gamma rays and fusion explosions would turn the atmosphere from space to the surface into a huge ball of plasma before disappearing through the crust with no chance of being stopped due to their crazy speeds. Not only would it probably have enough momentum to knock Earth from its orbit, it'll probably have enough speed to out-power the Earths gravitational binding energy and scatter the Earth across the Universe like it were a supernova of its own.

Finally a Hollywood movie worth watching!

[dustinsonger]

^ that's assuming earth could even form in a universe like that

[Michael Kim]

And given the divergence you get under assumption of uniform distribution, the observable universe is big enough to be "almost" infinite. Yes, the luminosity of the finite universe is going to be finite, but it still works out to be absurdly bright. It's not. It's pretty dark. So whatever the long distance behavior is, it's not divergent. And if it's not divergent, the actual size is irrelevant. With infinite c, you'd still get a convergent brightness.

You didn't get it here.

If light speed is infinite (which means we can receive every bit of light running towards us), and

1) the universe is finite, then the brightness will be finite;

2) the universe is infinite, then the brightness will be infinite.

You were right about Olber's Paradox has nothing to do with light speed. In fact, even though light speed is c, we still receive every bit of light running towards us. And the reason for the paradox not happening is that the observable universe is finite.

Also, why do you say that our universe is big enough to compare to, say, Olber's size? Mind that the density of luminous matters is really low. Well, speaking of this, we may also say that the reason for Olber's Paradox not happening is the low matter density. But low matter density and small size are actually the same, as the two factors are multiplied.

[Michael Kim]

You CANNOT even think it of some kind of reality. You can only assume you're telling a fairy tale.

Because WHAT THE UNIVERSE BE IS WHAT THE REALITY BE. Maybe hard to understand...

All right, uhmm... You know, this is the fundamental rules of physics, which reflects "reality" called by some of us. The reality is reality. It is how we exist. If you wipe it out, we can only say...

There could be an universe with different laws of physics. It's just hard to imagine.

You are trying to divide by zero or making 1+1=3.

And I don't think this is a good comparison, since maths is based on definitions (where things are DEFINED), but physics is based on experiments (or real events, you could say)

[Jokurr]

The super intelligent alien who created our universe in his computer program would get a divide by zero error.

[Michael Kim]

Earth might simply be destroyed. A Supernovae that launches protons and particles at us at what would have been relativistic speeds, but thanks to the lower energy requirements (linear acceleration) is now traveling hundreds of millions of kilometers per second faster than C would hit the Earth. The molecules in the atmosphere wouldn't have time to get out of the way of these faster-than-c particles and would fuse with the atoms and particles from the super nova, each collision releasing huge bursts of gamma rays and even more post-luminal scattered particles. Those gamma rays and fusion explosions would turn the atmosphere from space to the surface into a huge ball of plasma before disappearing through the crust with no chance of being stopped due to their crazy speeds. Not only would it probably have enough momentum to knock Earth from its orbit, it'll probably have enough speed to out-power the Earths gravitational binding energy and scatter the Earth across the Universe like it were a supernova of its own.

Finally a Hollywood movie worth watching!

This idea is interesting, but have you ever thought about how can those super-energetic particles be made? The total energy of a supernova is probably not going to differ much under another set of laws of physics, otherwise... will there be a supernova?

[InfinityArch]

Correct me if I'm wrong, but didn't Newtonian-era physics establish that light had a finite speed, but just fail to realize the significance of the constant c? Infinite light speed would break many, many, things even if we take away relativity.

[Holo]

Earth might simply be destroyed. A Supernovae that launches protons and particles at us at what would have been relativistic speeds, but thanks to the lower energy requirements (linear acceleration) is now traveling hundreds of millions of kilometers per second faster than C would hit the Earth. The molecules in the atmosphere wouldn't have time to get out of the way of these faster-than-c particles and would fuse with the atoms and particles from the super nova, each collision releasing huge bursts of gamma rays and even more post-luminal scattered particles. Those gamma rays and fusion explosions would turn the atmosphere from space to the surface into a huge ball of plasma before disappearing through the crust with no chance of being stopped due to their crazy speeds. Not only would it probably have enough momentum to knock Earth from its orbit, it'll probably have enough speed to out-power the Earths gravitational binding energy and scatter the Earth across the Universe like it were a supernova of its own.

Finally a Hollywood movie worth watching!

Nope, the particles would still have the same amount of energy. They would just be able to go faster with less energy, but if a baseball can't knock earth out it's orbit, FTL protons can't either.

[popeter45]

i could got to that cafe at the universe in no time!