I'm sure this has been asked a million times but,

Deeviant

russ_watters, I agree with what the basics of what you and most the rest of you are saying, but I must disagree with your statement that I learn nothing from asking these questions. These are question my (flawed?) intuition is asking, and I must not only understand the correct answer but I must understand the path to the correct answer. So yes, I am asking the "wrong" questions but I am doing so because I want to understand why they are wrong and in what way my view of the universe is biased.

For example this is the path my mind takes on my problem.

you have a pole a light-year long, the space tug grabs one side and starts to pull and lets say it accelerates to nearly the speed of light.

I can see a couple of different things happening:

1. If it didn't stretch, the end would move instantly. OR it would take an infinite amount of energy to move it, thus relativity is preserved. Relativity has already been proven wrong under certain circumstances(on the quantum scale) so how would I know this would not be another case of the breaking down? I not arguing I'm searching for understanding.

2. It would have to stretch, and if you figure that the space tug accelerated to nearly the speed of light, by the time the other end moves, which would be about a year, the pole's length would be nearly twice as long. I guess this would be what would happen but it just doesn't jive with my intuition(damn my intuition). Is this stretching the same idea that is frequently associated with releativistic movement, the warping of physical dimension caused by relativity?

3. It would break, this isn't very interesting although it is extremely likely.

I guess I just want to understand what exactely the speed of light is. I know it has something to do with the mass of a body in motion approaching infinity, but perhaps my real question is why does the mass increase. Is this effect like gravity before relativity in which we have laws to describe it but are completely unable to say what what the effect is caused by. Or have I simply been protected from the truth in my education because the answer is thought to be too complex for the average joe?



And on a completely different note,

As far as what Russ was saying:
The "all we know is that we don't know much" doesn't have to "get very far in figuring out what we do know," since all one has to do to find out what we do know is simple: be an effective gatherer of information, read up, keep up with current events. Basically it doesn't take much effort to do, althought understanding it perfectly may.
I'm not saying that the science we have now is invalid or not useful, it goes without saying that is extremely successful in explaining a wide range of phenomenon. I'm just saying its useful to take a step back sometimes, to exit the current framework and see whats out there(ie. string theory).

A quick look back in humanitity's past can lend many examples of the usefulness of this approach. For thousands of years man thought the earth was the center of the universe, only through the effort of a few that were willing to accept the fact that their vison of the world was incomplete were able to pur forth the correct theory.

I could go on but I'm sure you could get the gist of where I'm comming from on this.

russ_watters

Relativity has issues on the very small scale only. Not on the very large scale. Huh? Well, I guess your intuition is doing ok - the reason it doesn't jive with your intuition is its meaningless babble. You realllllly need to get away from these convoluted, contrived, false premise hypotheticals. They are utterly meaningless. You need to learn how the box looks from the inside before you can speculate about what's outside of it. That's a cop out - if its so easy, why haven't you done it yet? If you did make the effort to learn these things (relativity itself doesn't take much effort to understand in a basic way), then these questions you are asking would never come up. You'd understand why they are meaningless. Nope. Virtually nothing was known about science until the scientific method was invented in the 1500s. What happened before that is largely irrelevant because they didn't even have a process by which to figure anything out. That's the way you're approaching this: blindly. You won't learn much for the same reason they didn't learn much. Yes, we understand perfectly well where you are coming from - and we're trying to help you fix it.

selfAdjoint

Who says relativity is false in quantum theory? All the advanced quantum theories including string theory and the standard model are explicitly (special) relativistic. The only quantum theory that isn't is the original, pre-Dirac version. That is still useful where slow speeds can be assumed, but it isn't accepted as the last word on describing nature.

If you mean the inability of GR and quantum theories to be joined, the jury is still out. Maybe it's quantum that will have to give?

If you mean the Planck scale, nobody has the faintest idea what happens at the Planck scale.

Bottom line, there is nothing definite, nothing but predjudice, that says relativity has failed at all.

Deeviant

Well Russ thank you for the time it took you to reply but once again as DW before and you know, I fail to see why you made the post in the first place.

You neither answered any of the questions, nor really added anything in a constructive way. Sure I may be asking the "wrong questions" that are "convoluted, contrived, false premise hypotheticals" and are "utterly meaningless." I wasn't and I am not trying to prove why relativity "relativity is false" I was simply trying to ask knowledeable people who perhaps wouldn't mind explaining it.

And I find you statement: "If you did make the effort to learn these things (relativity itself doesn't take much effort to understand in a basic way)" ironic as the reason I posted in the first places was exactely for this reason, an effort in learning relativity. I do understand relativity "in a basic way" but I want to know it better, not what the theory says but how it workds. I'm sorry my "meaningless" qestions are so far below you.


One more thing, the scientific method. The statement "The first step in knowing anything is know that you know nothing" is a precept. It is seperate from a process as you called it. It is not a cop out and its very roots lies in your main argument against it: the scientific method. It is derived from the idea that in order for a theory to be valid it must not only be proven to match the hypothesis with experimental data but it also must be able to be proven wrong. Hince while working with a theory, trying to understand a theory a useful, meaningful and scientifically valid approach would be to try to prove the theory is wrong. Even if you know the theory is correct, information and knowledge can be gleaned from this process, such as, why the theory works, and also how the theory works.

This is obliviously not a place for learning, or sharing or even cooperation, just by looking at the themes of the posts here it has become painfully clear that this is a place for "smart" people to berate other's and stroke their own intellectual ego.

master_coda

Speculating from a false premise doesn't really gain you any knowledge of how the theory works. None of the results derived from the premise have validity in a universe where the premise is not true.


Not that there's anything wrong with speculating about how things would work in a universe with different laws of physics. But you can't learn anything about our universe that way.



Since the only purpose of that remark is to stroke your own ego, you obviously have something in common with the people you are berating.

HallsofIvy

I looked at the website link. It has exactly the formula I used.

It says: [tex]\frac{u_x-v}{1-\frac{vu_x}{c^2}}[/tex]
which is the same as my (u+v)/(1+ uv/c²) since the two objects are moving toward each other rather than away.

DW: Thank you for defending me (especially since I did not look at this thread for some time after) but Phobos is right- simply telling a person he is wrong without any explanation is not helpful.

DW

You're welcome. Phobos isn't right as I actually did have an explanation eluded to in a hint footnote to promt to reader to realize why that was, but which he deleted.

russ_watters

We really are trying to help you. The help you need isn't meaningless answers to meaningless questions, but a push in the right direction. Right now, your inquiries are taking you in the wrong direction.

Phobos

I disagree, particularly since the reader is a new member, but you're welcome to send me a PM about it.

Arcon

Did you follow the derivation that I posted? It takes a little understanding of math though. If you don't know math then please let us know so we don't try to explain in a language (i.e. math) that you're not familiar with.

You started this thread by asking If your in a ship traveling at the speed of light - The problem with that question is that it starts out by assuming something which the theory of relativity implies is impossible. It's like asking a question which starts by saying "Suppose I can create energy out of nothing..." - That too starts by assuming something which physics states is impossible. So you're left with either of two things (1) relativity is right and therefore you're assuming something impossible or (2) relativity is wrong and therefore, while your question has meaning, there is no theory which can address it.

If, on the other hand, you wish to find out why relativity holds that nothing which has mass can travel at the speed of light, or why a man in a spacecraft, which is moving at v = 0.99999999c relative to frame S, is moving inside the spacecraft, frame S', and thus relative to it, at v = 0.9999999c can't be traveling at a speed faster than light as measured in the first frame of reference S - then that has an answer. And it is shown with the link I gave at the beggining of this thread.

There are some people here with a poor attitude. Don't let them spoil it for you.

Arcon

Phobos

enough