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[Dutchling]

Why isn't anything supposed to move faster than light anyway? 

[Darvi]

Because time starts flowing sideways if that happens.

[TheBronzePickle]

Basically, the biggest justification that I've heard is causality. Basically (as far as I know), no matter what frame of reference they're in, everyone must at least have the ability to notice the cause of something before they can notice the effect. Basically, since light is the fastest thing in the universe and nothing goes faster that we can really sense, if something goes faster than the speed of light, that means someone in the direction it's travelling could possibly see the effect (the object moving) before the cause (whatever got the object moving) which breaks causality.

[MonkeyHead]

That, and the effects of mass/energy interchange. As an object gains kinetic energy (i.e. gets faster), there is an exponential increase in its mass. As it approaches light speed, this rate of mas increases tends to infinity - in other words, causing an object to go at lightspeed would mean you had to move an object which was in posession of an infinite mass, requiring an infinite amout of force (infinite amout of work done), which is just silly.

[kaijyuu]

Lots of things go faster than the speed of light. Just, you know, nothing you can measure or send messages with, or anything that has real mass. Theoretical particles like tachyons do, though. ('course since we can't measure them or anything, the question arises if they really exist or are just something we made up to explain weird behavior, heh)

[Kogan Loloklam]

I don't buy backwards time travel for anything from faster than light.
It seemed to me when Einstein was providing examples, he was deliberately not stating that things travel in time, but only our perception of the event changes and the rate of entropy slows down.
He never gives any examples that I could see that has an object departing before it left.
It's a tree falling in the woods making a sound if you pay attention or not, is what it seems he says. Sort of the opposite of the poor cat in the box.

[Criptfeind]

Basically, the biggest justification that I've heard is causality. Basically (as far as I know), no matter what frame of reference they're in, everyone must at least have the ability to notice the cause of something before they can notice the effect. Basically, since light is the fastest thing in the universe and nothing goes faster that we can really sense, if something goes faster than the speed of light, that means someone in the direction it's travelling could possibly see the effect (the object moving) before the cause (whatever got the object moving) which breaks causality.

I don't see what the issue with that is. If we use neutrinos to go faster then the speed of light that only bumps up the fastest way of getting information correct? causality is fine?

[Bauglir]

Using the speed of light as the constant in all the equations in relativity (of which I know little) gets results that match up pretty damn well with observations, so there's that. I think the reasoning for it probably has something to do with photons being a particle that mediates a fundamental force (electromagnetism), and you can actually calculate an exact value for it from that instead of having to rely on observation. Because I think it's not that the speed of photons sets a limit, it's that there's a limit that photons (and, I think, the particles for the other forces as well, but don't quote me on that) travel at. Anyway, I don't think there's any particular reason for neutrinos to travel at that limit, much less above it.

Feh, physics gets further away into my past with every year. Physics students, correct the hell out of my ramblings, please.

[Miggy]

Why isn't anything supposed to move faster than light anyway? 

The theory of relativity predicts this, and most if not all of the observations made through the theory of relativity is based off of it. If things travel faster than the speed of light, the theory of relativity has a flaw, which means all the subsequent explanations have flaws as well.

And why is it then so hard to abandon relativity? Because through the observations made through relativity, other equally puzzling phenomena can be explained. For instance, at a quantum mechanical level the concept of electron spin is not explained until you use relativistic observations. And we're pretty damn sure we're on target with electron spin. So how could a faulty method give us the right answers?

[Dsarker]

Why isn't anything supposed to move faster than light anyway? 

The theory of relativity predicts this, and most if not all of the observations made through the theory of relativity is based off of it. If things travel faster than the speed of light, the theory of relativity has a flaw, which means all the subsequent explanations have flaws as well.

And why is it then so hard to abandon relativity? Because through the observations made through relativity, other equally puzzling phenomena can be explained. For instance, at a quantum mechanical level the concept of electron spin is not explained until you use relativistic observations. And we're pretty damn sure we're on target with electron spin. So how could a faulty method give us the right answers?

We have a Mr Isaac Newton to see you.

[Miggy]

Why isn't anything supposed to move faster than light anyway? 

The theory of relativity predicts this, and most if not all of the observations made through the theory of relativity is based off of it. If things travel faster than the speed of light, the theory of relativity has a flaw, which means all the subsequent explanations have flaws as well.

And why is it then so hard to abandon relativity? Because through the observations made through relativity, other equally puzzling phenomena can be explained. For instance, at a quantum mechanical level the concept of electron spin is not explained until you use relativistic observations. And we're pretty damn sure we're on target with electron spin. So how could a faulty method give us the right answers?

We have a Mr Isaac Newton to see you.

Exactly, this is why everything is so exciting and worth a big uproar. These things have happened before, most notably and recently the move from classical to quantum mechanics. That move gave us tremendous insight into how the world works and explained a host of things we never could explain before. Maybe we will now be forced to move from special relativity to.... Special special relativity? VIP relativity?

[Darvi]

Does that stand for "Very Improbable Particle"?

[Dsarker]

Why isn't anything supposed to move faster than light anyway? 

The theory of relativity predicts this, and most if not all of the observations made through the theory of relativity is based off of it. If things travel faster than the speed of light, the theory of relativity has a flaw, which means all the subsequent explanations have flaws as well.

And why is it then so hard to abandon relativity? Because through the observations made through relativity, other equally puzzling phenomena can be explained. For instance, at a quantum mechanical level the concept of electron spin is not explained until you use relativistic observations. And we're pretty damn sure we're on target with electron spin. So how could a faulty method give us the right answers?

We have a Mr Isaac Newton to see you.

Exactly, this is why everything is so exciting and worth a big uproar. These things have happened before, most notably and recently the move from classical to quantum mechanics. That move gave us tremendous insight into how the world works and explained a host of things we never could explain before. Maybe we will now be forced to move from special relativity to.... Special special relativity? VIP relativity?

I've got little to no real understanding of physics; however, I was pointing out that Newtonian physics is still used when there is no need for quantum physics or relativity.

[MonkeyHead]

Yea, you dont need relativity unless you are dealing with the very big or very fast. SImilarly you dont need quantum unless you deal with the very small or very close. So in all probability should these measurements pass further scrutiny and move beyond doubt (some way to go there though), all that will happen is a specialized theory to explain the behavour will be developed which probably wont reconcile with quantum mechanics or relativity, making it even harder for those of us working in Physics to come up with a GUT (grand unified theory)...

[Miggy]

Yea, you dont need relativity unless you are dealing with the very big or very fast. SImilarly you dont need quantum unless you deal with the very small or very close. So in all probability should these measurements pass further scrutiny and move beyond doubt (some way to go there though), all that will happen is a specialized theory to explain the behavour will be developed which probably wont reconcile with quantum mechanics or relativity, making it even harder for those of us working in Physics to come up with a GUT (grand unified theory)...

Any explanation won't be an explanation until it reconciles with both classical and quantum mechanics, as well as special relativity. It would basically be saying "A wizard did it".