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[qwertyuiopas]

As you approach the speed of light, the mass increases, and at a higher mass, the energy required to increase your speed increases too.
So you end up getting closer and closer in smaller increments, unless you have alien technology.

Besides, you still can go as fast as the speed of light, since space isn't a complete vaccuum by scientific standards, so light out there travels something like .00000000001% slower.

[Yanlin]

Personally I see this time travel crap as nonsense. If I go faster than light, then light will lag. Just like if I go faster than sound. Sound will lag. Horribly. Now this is where the time thing comes into play.

We do not see stuff. We see the light they reflect. The stuff you see on your monitor? You are seeing them just a tiny bit later than they actually appear on screen. In fact, you see the moon a whole 1 second late. You also see galaxy Andromeda with lag of 2 billion years. That means, you see it as it was 2 billion years ago. Since light has a speed. It has to cover a distance before it reaches you.

Now if you go faster than light, you arrive to your destination before light does. This enables complete stealth from all visual sensors. But this all goes out the window. Since you reflect light ALL THE TIME, once you arrive you will be reflecting light to be picked up. Even if the light you emitted a while back shows you aren't there yet.

Now time dilation... That shit needs some proof...

[Sowelu]

I was under the understanding that the 'speed of light' is more properly called the 'speed of causality'.  Quantum entangled particles don't reflect a changed state until (distance / c) time-units later.  Heck, GRAVITY only works at the 'speed of light', if you move an object very fast then other things are attracted to it based on its position (d / c) ago.  Information can't travel faster than c, regardless of what's in between (or not in between).

It's a fun thought experiment to think of the universe as running on God's supercluster of computers.  They don't lag exactly, but they only talk to each other at a certain speed.

I can only imagine what bad things would happen if you moved faster than the signal containing your very existence could propagate.

[dreiche2]

@Yanlin

Uhm, dude, you can't go faster than light according to current physics. This whole faster than light business only matters for some obscure quantum mechanical effects, if at all, and has no relevance to any normal matter.

And that "shit" has been confirmed repeatedly for about one hundred years now and is a corner stone of modern science. It's pretty complicated in parts, yes, but still.

[Yanlin]

"Current physics" still did not prove it is not possible to travel faster than light.

Face it. We do not know the all the laws of physics. Science has a fatal flaw. It cannot prove something doesn't exist. Or that something cannot be done.

I need proof before I believe anything. So far there has been little proof to say faster than light travel is impossible. Most of said proof was also bad proof.

We just don't have the technology to go faster than light. Hell we know light is a particle and a beam. Which means it is possible for particles, matter, to go that fast. Maybe even faster.

[dreiche2]

That's actually why I said "current" physics. Science is not about proving things, it's about finding the best explanations for what happens until something invalidates the current explanation, and then you look for a better explanation that agrees with the new data.

You can never prove a theory, you can only invalidate it - I guess that's related to what you said. However, if you're not happy with that, then science just doesn't work for you.

It's like you can't prove that two masses will attract each other. You can make an experiment a thousand times, but who know what happens the next time?

As for not being able to travel faster than light, well that's what the current theory says in line with the current data. There might be a flaw in the theory, but that's always a possibility. More likely, current physics is far from complete, but the limit of the speed of light is not the issue.

Similarly, the current theory says, if you jump out of the window (without a parachute etc.), you won't suddenly levitate away. Hard to *prove* it won't happen, but hey, I wouldn't bet on it.

As for particles, well yeah, particles without rest mass can travel that fast... such as light.

[Yanlin]

Agreeing to one thing just because it lacks proof is a bad idea.

[Sean Mirrsen]

If we compare the speed of light to the speed of sound, we might draw neat parallels.

You can only travel so fast in the air because the very air itself - "vibrations of air" - can propagate that fast. You try to go faster, and you need to rip through the mass of air, use tremendous power to overcome the escalating compressive force that gets built up, and some sturdy material to protect against the force.
Now consider universe. Just about anything in the universe travels at the speed of light. Radiowaves. Light. Just about every EM emission type. Since even something like radiowaves (I still can't imagine radiowaves. Yes, I can understand the wave mechanics. What I fail to understand is how radiowaves interact with stuff. Wouldn't they need to phase in and out of existence to be waveform in relation to 3D space?) travels at light-speed, you will face the same compressibility barrier when you reach light-speed. Except you're going to need something that is more powerful than the universe, and stronger than energy itself, because any material object will be ripped apart at a subatomic level by the sheer pressure of energy and resonance from overlapping waves. And that's not taking possible relativistic clauses into account.

[dreiche2]

Agreeing to one thing just because it lacks proof is a bad idea.

Hu?

Also, it is *impossible* to prove faster-than-light speed is impossible. It is also impossible to prove you won't levitate the next time you jump out of the window.

If you want to get an impression whether it is *reasonable* (subjectively) to assume that there is this hard limit given the data and given the theories, then I'm afraid you'll have to go ahead and study physics.

@Sean

No, comparison with the speed of sound is not a good idea, because those things are exactly *not* alike in many ways - such as, well, you can actually travel faster than the speed of sound. And, the equivalent of air for light, namely an aether in which light would propagate, is exactly what the theory of relativity got rid of...

As for the original time dilation problem, sorry I was a wee bit cheeky, I'm going to write an explanation later.

[beorn080]

@dreiche2: Given current physics, and throwing the universal speed limit out the window in a fictional setting, it would be possible to use C+ weaponry like that. Please read the entire post. All this talk is based on FICTIONAL UNIVERSES.

@Sean: From what I recall of my AP physics class, its a 3-d waveform. I forget the exact hertz to meter conversions, but essentially it travels in a pulse that expands and contracts as it it emitted. If you want a practical application of this, stick an ant in a microwave and watch as it doesn't die from boiling blood. This is because it can slip between the waves as they travel.

[Sean Mirrsen]

Err, that's actually a very wrong idea there. Just because you can travel faster than sound does not mean you can travel faster than light if it works on the same principle. And I'm not speaking of any "aether" either. Space is always full of energy - at the very least it's reflected and emitted light from anywhere in the universe. That's energy right there. If you move at the speed of energy's compressibility limit, you're gonna have to tear through energy to move faster. Light always moves with a definite speed because it cannot move faster than the universe allows waveforms to propagate, and there is no intervening physical mechanism to make it slow down further.

beorn: I can understand a pulse-wave thing. As in, you spontaneously compress a region of matter, and the matter will propagate in a wavelike pulse. Why does it work for radiowaves though? Wouldn't it imply a medium consisting of the same energy?

[sonerohi]

Oh lordy. It seems I accidently derailed the thread into a discussion of all sorts of science and physics.

[dreiche2]

Hey, but I like physics!

Sean, I'm just saying that your metaphor/analogy is not a very good one.  "Tear through energy" might be an image in your head, inspired by the sound issue, but it just doesn't really apply to light like that.

It starts with that in your own frame of reference, the speed of light is always constant. When you say you reach the speed of light, than that's from someone else's frame of reference.

Basically, when you sit in your space ship and continuously accelerate, then you will see the stuff around you like planets approach the speed of light (slower and slower, asymptotically). Light itself will still have the speed of light though from your view. There is no barrier to break through (if anything, it would be everyone else in the universe that would be approaching that barrier, from your point of view).

[Sergius]

I don't think light sets up some sort of speed limit for us (can't go faster than light, no siree), but rather than the "speed of light" is holding light back. So light is being "slowed down" (or simply there is no possible higher speed).

In the case of the speed of sound, it's the sound itself that is doing damage to stuff going exactly at that speed (it's like you're constantly crashing with your own sound). So in theory, making a perfectly silent engine/airplane/whatever wouldn't suffer from this (but easier to just accelerate really fast and leave the sound behind as quickly as possible)

There goes my layman's explanation of something I arbitrarily believe to be true. For Science!

[Sean Mirrsen]

Heh, and I think that light's speed is constant from a relativist's point of view. Light cannot go faster than it can because it cannot overcome the compressibility of energy, being a wave. Light is neither a particle or a wave for this reason - it's a dense waveform going at the highest allowable speed, breaching into "particle space". Since, per my belief, all matter in the universe is just dense energy (probably tiny patches spinning at the speed of light, held by some small powers we can't yet understand), then a patch of energy within a specific frequency will be overwhelmed with its own resonance when going at the highest allowable speed, and thus partially become matter. It's a waveform-particle like that.