[Mura]

GOOD NEWS EVERYONE!

That warp drive... it was invented by Profesor Hubert Farnsworth, it's a drive that moves space around the ship, not the ship in space! (kind of  )

[NGTM-1R]

I think putting the ship into a mass neutralizing field counts as 'not real space'.

It's actually exploiting a loophole that may or may not exist and giving the ship negative mass in real space, thus allowing it to exceed the speed of light.

...in theory.

[Bobboau]

which I would file in the folder marked 'Not Real Space'

[Roanoke]

Personally I don't think we (mankind) know enough to arbitrarily denounce FTL as impossible......tbh though I don't really understand why FTL has to involve time travel ?

[The E]

It's a consequence of Einstein's special relativity, which basically states that any form of faster-than-light travel is functionally equivalent to time travel.

[SpardaSon21]

Let me quote good old Professor Farnsworth:

Take that causality!

[newman]

tbh though I don't really understand why FTL has to involve time travel ?

Because only a DeLorean is capable of exceeding speeds of 300,000 km per second, and it starts traveling through time at 88 mph. If and when it starts, that is.

[General Battuta]

If your outside references do not have the capability of receiving/transmitting FTL signals, then they cannot observe the FTL transaction and then the discussion of IRFs is moot.

They can still see the FTL ship arriving out of nowhere and blowing itself up before it's even finished being constructed.

Paradox.

[Bob-san]

Here's another idea: why do teleporters have to copy all your information, destroy it, and reproduce it on the other side? Wouldn't it make more sense to copy and send instead of copy, delete, and send? After all, if you could possibly send all this information lightyears away, would you want to spend the years traveling it or would a copy of you rather appear on the other side with no perception of time lost and no fatigue or degradation. I think our larger problem than reproduction is getting all the information instantly yet accurately. Besides, it'd be kind of cool to know that I flaked out of time for science.

[Mika]

Assuming a time like particle such as a photon, what would it be like to be one? How does it see the world? What happens in the interaction between matter and photon? My limited understanding is that the photon itself doesn't age, but what else is there? This is a rather fun topic since I deal with photons every day in my work. But I have never really needed to think what really goes on there, as I can usually reduce them to rays. Come to think of it, how does the polarization even work in corpuscular model? What is it that my photons do to make the electrical field appear as polarized?

Electrical field = a cloud of small flishy-flashy wobbling balls that go extremely fast. That seen from their perspective, don't age at all. And pre-scan their direction of travel through whole spacetime, and then select the shortest route - and only after that, travel through it, lazy bastards. If somebody tries to outsmart them with interference stuff, they counter by interfering with themselves. Yeah, I wish I could make this up, but this just keeps getting better and better. Sneaky bastards those photons.

[General Battuta]

Here's another idea: why do teleporters have to copy all your information, destroy it, and reproduce it on the other side? Wouldn't it make more sense to copy and send instead of copy, delete, and send? After all, if you could possibly send all this information lightyears away, would you want to spend the years traveling it or would a copy of you rather appear on the other side with no perception of time lost and no fatigue or degradation. I think our larger problem than reproduction is getting all the information instantly yet accurately. Besides, it'd be kind of cool to know that I flaked out of time for science.

The deletion is certainly not a necessary step (barring the need for destructive scanning to achieve sufficient resolution?), but it makes many people more comfortable because it preserves the illusion of a unitary conserved self.

[Bobboau]

They can still see the FTL ship arriving out of nowhere and blowing itself up before it's even finished being constructed.

Paradox.

what it would look like and what was real are not necessarily the same things, if you look at a straw in a cup of water the different indices's of refraction of water and air will cause the straw to appear to be bent, when in reality it's actually quite straight. just because you can see a pair of space ships engage in a climactic final showdown that determines the fate of the galaxy before you can see traces of bronze age civilization on the planets from which they originated does not mean that, that is the actual state of those planets.

[General Battuta]

They can still see the FTL ship arriving out of nowhere and blowing itself up before it's even finished being constructed.

Paradox.

what it would look like and what was real are not necessarily the same things, if you look at a straw in a cup of water the different indices's of refraction of water and air will cause the straw to appear to be bent, when in reality it's actually quite straight. just because you can see a pair of space ships engage in a climactic final showdown that determines the fate of the galaxy before you can see traces of bronze age civilization on the planets from which they originated does not mean that, that is the actual state of those planets.

Again, this is that common misconception that relativity is all an optical illusion. It's not that at all.

In this case we are not talking about what things look like. We are talking about what is real. And that is because the speed of light is an utter invariant which defines the causal separation of events.

For example, a person moving near lightspeed will see a meter-long stick (at rest in our IRF) as shorter than a meter. This is not an optical illusion. The stick has actually contracted...in that IRF. In our IRF it hasn't. Both IRFs are equally valid. Objects have different lengths (and masses) depending on the relative velocity of the observer.

Similarly in this case, the events actually swap order; the perception of the events is not all that's changed, the order of the events themselves has.

If you need more convincing I'll walk you through an introductory example I'm fond of.

[StarSlayer]

They can still see the FTL ship arriving out of nowhere and blowing itself up before it's even finished being constructed.

Paradox.

what it would look like and what was real are not necessarily the same things, if you look at a straw in a cup of water the different indices's of refraction of water and air will cause the straw to appear to be bent, when in reality it's actually quite straight. just because you can see a pair of space ships engage in a climactic final showdown that determines the fate of the galaxy before you can see traces of bronze age civilization on the planets from which they originated does not mean that, that is the actual state of those planets.

Again, this is that common misconception that relativity is all an optical illusion. It's not that at all.

In this case we are not talking about what things look like. We are talking about what is real. And that is because the speed of light is an utter invariant which defines the causal separation of events.

For example, a person moving near lightspeed will see a meter-long stick (at rest in our IRF) as shorter than a meter. This is not an optical illusion. The stick has actually contracted...in that IRF. In our IRF it hasn't. Both IRFs are equally valid. Objects have different lengths (and masses) depending on the relative velocity of the observer.

Similarly in this case, the events actually swap order; the perception of the events is not all that's changed, the order of the events themselves has.

If you need more convincing I'll walk you through an introductory example I'm fond of.

Walk IT!!

[General Battuta]

Okay.

For this to work, you need to be aware of an experimentally demonstrable starting point: the speed of light (C) is the same no matter how fast you're going.

This is really weird. Normally, if you see a guy drive past at 30 mph, and he throws a ball forward from his car at a speed of 30 mph, the ball's gonna be going at 60 mph from your POV. But if that guy turns on a flashlight, the light won't move at C+30; it'll move at C.

This in turn suggests that to the guy driving at 30 mph (the wimp), the light is moving at C-30 from his POV...but no, even to him it's moving at C.

This is bizarre but true.

Right.

Imagine that Axem and I are going to have a gun duel. Because we're awesome, we're going to have this duel on a moving train car. Axem will stand at the front end of the car, and I at the rear.

When a light positioned exactly in the middle of the train car flashes on, that will be the signal to draw and fire. So as soon as the pulse of photons from the light, moving at C, strikes our eyes, we will fire.

We want to be extra sure that the duel is going to be fair, so we hire The_E to stand in the train car with us and verify that the light reaches each of us simultaneously. Since Axem,  The_E and I are all inside the moving car with the light, we are all stationary relative to each other.

However, Axem's crazed fan Cobra sneaks onto a train platform that we pass at just the moment the light flashes. To Cobra, the train car - and the duelists within it, as well as the light - are moving rapidly across his reference frame from his left to his right.

Does The_E conclude that the duel is fair?

Does Cobra conclude that the duel is fair?

Recall that the speed of the light is independent of the motion of the source and that the criteria for fairness is that the light pulse reach both Axem and Battuta simultaneously.

Here's a picture:


| BATTUTA ........... LIGHT ............ AXEM|   ------------------------------> direction of travel
                  
                             COBRA

[StarSlayer]

Seems like an awful waste of good HLP members.  If you kill Axem just remember you're filling his shoes for Diaspora.

[General Battuta]

Seems like an awful waste of good HLP members.  If you kill Axem just remember you're filling his shoes for Diaspora.

thees was my plan all along

[Bobboau]

ok, so this does show that time slows for objects that move normally through space. the implication being that moving faster than light would cause time to flow backwards for that object, but perhaps there is some as yet unknown mechanism that could neutralize time dilation to some extent, this would break the rules of relativity that require the speed of light to be the speed of propagation in the universe. no matter what reference frame you work in time is always moving forward, so the only problem with FTL in this since is that time in an FTL frame would move backwards, so if this effect could somehow be countered then causality could be preserved. now this is just pie in the sky, but we all know that there is no known way to achieve FTL, and all we are talking about is the causality problem, so playing what if on the known rules I think should be acceptable.
so if we ignore the fact that moving faster than the speed of light would require more than infinite energy, would cause time for the moving object to travel backwards, would cause all objects to have negative dimensions and more than infinite mass, (I suppose this would be the same as modifying what C equaled within a local volume) I still don't see how cause and effect are effected by this. I am not aware of any observations that have established that C is the speed of event propagation, only that nothing has disproven it, and that it is the fastest propagation yet observed, though I'm not even sure how you would observe event propigation.

[Aardwolf]

Seriously, what about "subspace"-y schemes? Considering the object is effectively outside the universe as it's "in transit"...

Suppose you're doing a jump. If we define the IRF such that the position/velocity of the ship as it enters subspace is 0, and we require that the time of arrival be "later" than the time of departure (in that reference frame), and that the final velocity also be 0... (i.e. velocity in the original IRF is unchanged)...

 

If another ship near the point of arrival has the same capabilities, and is moving rapidly "away" from the original position, then the same issue would arise; it could jump to where the first ship started out, and could conceivably arrive before the first ship departed.

So that's no good either... unless some other restrictions could be devised.

Actually, I reckon these restrictions might be determinable mathematically.

[General Battuta]

ok, so this does show that time slows for objects that move normally through space. the implication being that moving faster than light would cause time to flow backwards for that object, but perhaps there is some as yet unknown mechanism that could neutralize time dilation to some extent, this would break the rules of relativity that require the speed of light to be the speed of propagation in the universe. no matter what reference frame you work in time is always moving forward, so the only problem with FTL in this since is that time in an FTL frame would move backwards, so if this effect could somehow be countered then causality could be preserved. now this is just pie in the sky, but we all know that there is no known way to achieve FTL, and all we are talking about is the causality problem, so playing what if on the known rules I think should be acceptable.
so if we ignore the fact that moving faster than the speed of light would require more than infinite energy, would cause time for the moving object to travel backwards, would cause all objects to have negative dimensions and more than infinite mass, (I suppose this would be the same as modifying what C equaled within a local volume) I still don't see how cause and effect are effected by this. I am not aware of any observations that have established that C is the speed of event propagation, only that nothing has disproven it, and that it is the fastest propagation yet observed, though I'm not even sure how you would observe event propigation.

When it comes to your latter question, see the thought experiment above. Consider the difference between The_E and Cobra's perceptions of the fairness of the duel, and the fact that it's the particular behavior of light that makes this weird asymmetry occur.