# Thread: Faster Than Light Travel

1. ## Faster Than Light Travel

Just a question here...
I understand that if a force is being exerted on an object, it will accelerate at a constant rate, and I wonder why it won't eventually break the speed of light?
I assume this is because there is not enough energy in the universe as we know it to create this much force.
Is this correct?

2. Hum,
the space time `fabric` can only support a certain `speed`, the extra energy that you pump into the object to make it go faster just gets converted to mass instead.

it is like a glass of water, the glass will only hold so much before it overflows...

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If the force is constant the object will not accelerate at a constant rate, because the mass will increase.

Non-increasing mass is a simplification of Newtonian mechanics that is accurate enough for all practical purposes at low velocities, but the errors become increasing large as you approach the speed of light.

4. So at the speed of light a material object would have to have infinite mass.

5. and would have required infinite energy to accelerate it.

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...at least according to the Einsteinian physics we know now.

(come back in a few centuries and that may or may not change!!!)

7. Bascially according Einsteinian Physicis there are three speed limits.

For anything with mass it is less the Light Speed, as it accelerates it gains mass. At the speed of light anything with mass, will have infinate mass, requiring it to have infinate energy to reach that acceleration.

For anything Massless (like light) they are limited to traveling exactly at the speed of light, unless externale forces are applied to them (they they can be slowed down and possibly sped up, both have been done experimentally now)

For anything with negative mass they are limited to traveling at speeds only faster then light. The less energy they have the faster they move. It requires infinate energy to slow negative mass down to the speed of light. Even if such particles as this exsit (Tacheons, etc) it's likely there would be no way to detect them with slower Photons or even slower mass.

8. What this means is that to move something Faster then Light, you need to do it without accelerating it. Or accelerating it at slower then light speeds, while altering space/time to make the distance shorter (compress space/time)

So only way around the limit is to either Warp space, travle in other dimensions, or outright quantum teleportation (which produces a copy, not the original at the destination)

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## superluminal

Originally Posted by Trivial Pursuit
Just a question here...
I understand that if a force is being exerted on an object, it will accelerate at a constant rate, and I wonder why it won't eventually break the speed of light?
I assume this is because there is not enough energy in the universe as we know it to create this much force.
Is this correct?
Trivial Pursuit: Experiments show that nothing will travel faster than the speed of light in the neutrino sea. As no experiment has ever been conducted in absentia of the neutrino sea, whether or not it is possible for light to travel faster there....we know not. pete
Last edited by trinitree88; 2007-Mar-25 at 08:18 PM. Reason: spelling

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This is so much more complex than it's often portrayed. A constant force will accelerate an object forever, as far as the object is concerned. All this mass increasing, time stretching, length contracting stuff only applies to outside observers. You can jump in your starship with it's constant acceleration engine and, providing you have the fuel, cross the galaxy in your lifetime. Don't expect to come back and tell your friends about it though, they will be long dead. They're the outside observers.

11. In the other hand, while doing this you'll see the rest of the universe gain mass, slow down, get squashed and so on, since you'll be the outside observer looking in on it.

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You can jump in your starship with it's constant acceleration engine and, providing you have the fuel, cross the galaxy in your lifetime.
Provided you are clever enough to detect and avoid objects that you might otherwise encounter and are able to knowingly navigate.

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Originally Posted by dgavin
Bascially according Einsteinian Physicis there are three speed limits.

For anything with mass it is less the Light Speed, as it accelerates it gains mass. At the speed of light anything with mass, will have infinate mass, requiring it to have infinate energy to reach that acceleration.

For anything Massless (like light) they are limited to traveling exactly at the speed of light, unless externale forces are applied to them (they they can be slowed down and possibly sped up, both have been done experimentally now)

For anything with negative mass they are limited to traveling at speeds only faster then light. The less energy they have the faster they move. It requires infinate energy to slow negative mass down to the speed of light. Even if such particles as this exsit (Tacheons, etc) it's likely there would be no way to detect them with slower Photons or even slower mass.

Sorry to be pedantic, but tachyons have imaginary mass not negative. It's to do with the root (1-nu^2/c^2) term. Particles with negative masses would still travel slower than the speed of light

14. Originally Posted by dgavin

For anything Massless (like light) they are limited to traveling exactly at the speed of light, unless externale forces are applied to them (they they can be slowed down and possibly sped up, both have been done experimentally now)
Light has not been slowed down.

Propagation of light has been slowed to almost a stop, these are entirely different things.

Both Harvard and Lene Hau **** me off for misleading the public.

15. ## Beyond that Sea

Originally Posted by trinitree88
Trivial Pursuit: Experiments show that nothing will travel faster than the speed of light in the neutrino sea.
If we consider that it is possible to go beyond this neutrino sea (in this life or the next), perhaps by distorting our mass as we move beyond the speed of light, so as not to hit anything in our way, then constant increase in speed would be no problem. Atoms traveling at the speed of light would act wildly different from other objects that they are passing, so could they even slip between objects because of their excited state at high speed?
As nothing in the material plane has reached such speeds, I expect no one can answer that right now, yet I await a plasma-fission power source that my get us that fast one day.
Why not?

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Originally Posted by Oahspe
If we consider that it is possible to go beyond this neutrino sea (in this life or the next), perhaps by distorting our mass as we move beyond the speed of light, so as not to hit anything in our way, then constant increase in speed would be no problem. Atoms traveling at the speed of light would act wildly different from other objects that they are passing, so could they even slip between objects because of their excited state at high speed?
As nothing in the material plane has reached such speeds, I expect no one can answer that right now, yet I await a plasma-fission power source that my get us that fast one day.
Why not?
individual particles of matter - protons, electrons, alpha particles( helium nuclei) have gotten awful close to the speed of light in our labs (human labs) and even somewhat closer from massive cosmic power sources. Suffice to say that they don't go whizzing between relatively stationary matter much better than much slower matter - they go splat really hard.

As for fission/fusion power sources for rockets, you'd be terribly dissappointed in just how much fuel it's going to take and how long it would take to make a trip to a nearby star - assuming you're not going to be splatted into your astronaut chair. The earth only has the resources for a relatively few trips of large craft with enough speed for relatively high time dilation without starting to have significant environmental impact.

17. Originally Posted by Blob
Hum,
the space time `fabric` can only support a certain `speed`, the extra energy that you pump into the object to make it go faster just gets converted to mass instead.

it is like a glass of water, the glass will only hold so much before it overflows...
So can you slow down and loose mass?

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Originally Posted by Miketmbt
So can you slow down and loose mass?
Is that why fat people walk slow?

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## strange water

Originally Posted by Blob
Hum,
the space time `fabric` can only support a certain `speed`, the extra energy that you pump into the object to make it go faster just gets converted to mass instead.

it is like a glass of water, the glass will only hold so much before it overflows...
Blob. I'm going to try an expansion of that analogy. If the laws of nature were such that the volume of a magic cylindrical glass of water is constant, then an odd thing would happen as you tried to fill it. The first monolayer poured on the bottom would seem to be on its' way to providing a route to the top, but the second layer would be distinctly different. While providing the same mass, it would have a slightly smaller volume. Layer by layer, as you pour, the water molecules shrink in size, becoming ever denser. So, the glass gets heavier and heavier but never full (according to gamma). Eventually, you'll be pouring water at black hole density..(it's just numbers).
When you empty the glass out, just the opposite occurs. First you pour out the black hole water, then ~ neutron star density, through successive density gradients down to the bottom monolayer of water (the only one). of "normal" water
With masses accelerating to c, even your initial minute acceleration from your rest frame has already changed your object's mass. Not all the energy you thought you were putting into delta v did that for you (though it's close, according to gamma). With every successive incremental acceleration, a larger and larger relative proportion of the energy you are applying goes into mass, (still according to gamma) until that too reaches black hole density.
"Waiter, could I have a refill on my water, please?" Pete.
Last edited by trinitree88; 2007-Apr-05 at 03:18 PM. Reason: forgot...please!

20. Originally Posted by Chip
So at the speed of light a material object would have to have infinite mass.
it depends, does light have infinite mass?

i don't think so

21. So could there be some kind of transfomation that once you reach the speed of light you have no mass?

Does gravity travel at the speed of light or does light travel at the speed of gravity?

22. One more question from me. E=mc2 means you can create alot of energy from a little bit of mass, correct? So. As you increase in mass when you approach light speed couldnt that mass create even more enery as you go?

23. Originally Posted by punkrockbong151
Originally Posted by Chip
So at the speed of light a material object would have to have infinite mass.
it depends, does light have infinite mass?

i don't think so
Light is not a material object, your objection is irrelevant.

24. Originally Posted by Miketmbt
So could there be some kind of transfomation that once you reach the speed of light you have no mass?
Nope, it would take infinite energy to get you there.

Infinite does not mean "a lot".

Originally Posted by Miketmbt
Does gravity travel at the speed of light or does light travel at the speed of gravity?
Yes.

25. Originally Posted by Miketmbt
One more question from me. E=mc2 means you can create alot of energy from a little bit of mass, correct? So. As you increase in mass when you approach light speed couldnt that mass create even more enery as you go?
Nope, because from your reference frame on the ship, the mass isn't increasing. So, there is no extra mass to use to make energy. The extra mass only exists in the reference frame of the outside observer.

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oh well, here goes

There was a young lady from Bright
who could travel faster than light.
She went out one day in a relative way
and came back the previous night.

Any thoughts on the potential disastrous consequences of that sort of stuff happening in the universe?

27. There once was a man named Fisk
whose fencing was exceedingly brisk.
So fast was his action
the Fitzgerald contraction
turned his rapier to a disk.

You started it!

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Originally Posted by cjl
Nope, because from your reference frame on the ship, the mass isn't increasing. So, there is no extra mass to use to make energy. The extra mass only exists in the reference frame of the outside observer.
and from perspective of outside observer energy from this mass can be created by slowing the moving object but this is just recapture of the energy to accelerate this object in the first place

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Originally Posted by HenrikOlsen
Nope, it would take infinite energy to get you there.

Infinite does not mean "a lot".
yes but statements about infinite energy to achieve the speed of light are limiting arguments only the proper meaning is for any amount of energy the object is always slower than the speed of light if the energy is increased the speed is increased but the speed as function of energy when energy grows wihtout bound approaches the speed of light asymptotically so with more and more energy you can achieve any speed slower than light but can never achieve speed of light itself

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## tachyons...fabric of spacetime

Originally Posted by cbacba
oh well, here goes

There was a young lady from Bright
who could travel faster than light.
She went out one day in a relative way
and came back the previous night.

Any thoughts on the potential disastrous consequences of that sort of stuff happening in the universe?
cbacba. It's why I don't buy into tachyons. Once you posit their existence, you buy into schemes like "The Sting", where mere mortals operating under the postulates of SR are your hapless victims. While there are still plenty of malicious schemes in the universe, an inherent malice in it's inceptual design doesn't seem to be one of them. We continue to make slow but tortured progress towards a knit set of principles, and there are always a few unexpected wrinkles in the fabric of spacetime.....collecting a few of those myself watching my brother's grandkid the other day... pete

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