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For once more dimensions make something much easier :)Quote:
The best way to think of spin is not to do it three dimensionally but to use higher dimensional plains.
When it was revealed (in the Horizon sciene program, that I Sinnersis watched too ) that 10 D string theory had problems, my flatmate joked that it would be solved by adding one somewhere...
Hmm, can't edit my message. The program was Horizon, on BBC2 in the UK.
Ilkpc has been sorely missed in this discussion. He hit upon many great points. One being; there is no such thing as a vaccuum. Why build theories around a non-existant? Einstein had to disprove a "universal frame of reference" for his theories to work because none could be found. Then he creates a vaccuum in order for some of his to work... The reason your stick looks broke when you stick it in the water is due to light being slown down. It has been slown to several MPH recently, and sped up to beyond C (well waves were propagated beyond C, but its a start!). Here's a link on the latter: Gain-Assisted Superluminal Light Propagation
A book that helped me understand the quantum world, and I'm surprised it hasn't been mentioned here yet, is Gary Zukav's The Dancing Wu Li Masters. Read that before Hawkings' and Greene's excellent work and you will save yourself a lot of headaches. Just stop at that work of Zukav's and don't continue with his recent Oprah-fied Seat Of The Soul garbage.
I may be wrong but it seems that some here are quoting things about the Uncertainty Principle without understanding it. The reason it is there is that, with fundamental particles, your observing them influences them. Read the aforementioned book for an in-depth explanation. On a side note: I did read something in the past few months and I can't remember where (probably Sci-Am or New Scientist) that some were "getting around" the Uncertainty Principle. If I dig up the link, I'll post it.
I don't think that this was the link I that I referred to in the previous post, for it is a few years old. Or could it be that my internal frame of reference (subjective) for a few months is that of a few years to the outside world (objective)? Ugh... these discussions... Anyways, it is interesting nonetheless.
Quantum nondemolition measurements
I think the link I was thinking about had to do with quantum computing. It probably did refer to this series of experiments though in their use in that field.
Blacktooth, it does say in that link that the experiment is not at odds with Einstein's relativity. Frankly I didn't read the whole thing so I can't explain why. But it said that flat out in the faq.
Also, blacktooth, you say why build theories about things that don't exist. The answer is because you need some basis for the theories. Since nothing is perfect, you need hypothetical perfection, probabilities and margins for error.
neelpeel, those collisions are EXACTLY identical, but thats not due to relativity, thats Newtonian physics - momentum.
Considering the force of both cars in the 50/50 senario would cancel each other out, and some of the energy of the 100/0 impact would just be transferred to the motionless car, the 50/50 impact would probably be worse.
While a perfect vacuum may not exist, reasonable approximations of the relevant properties of a perfect vacuum can be calculated.Quote:
Originally posted by Blacktooth
Ilkpc has been sorely missed in this discussion. He hit upon many great points. One being; there is no such thing as a vaccuum. Why build theories around a non-existant? Einstein had to disprove a "universal frame of reference" for his theories to work because none could be found. Then he creates a vaccuum in order for some of his to work... The reason your stick looks broke when you stick it in the water is due to light being slown down. It has been slown to several MPH recently, and sped up to beyond C (well waves were propagated beyond C, but its a start!). Here's a link on the latter: Gain-Assisted Superluminal Light Propagation
A book that helped me understand the quantum world, and I'm surprised it hasn't been mentioned here yet, is Gary Zukav's The Dancing Wu Li Masters. Read that before Hawkings' and Greene's excellent work and you will save yourself a lot of headaches. Just stop at that work of Zukav's and don't continue with his recent Oprah-fied Seat Of The Soul garbage.
I may be wrong but it seems that some here are quoting things about the Uncertainty Principle without understanding it. The reason it is there is that, with fundamental particles, your observing them influences them. Read the aforementioned book for an in-depth explanation. On a side note: I did read something in the past few months and I can't remember where (probably Sci-Am or New Scientist) that some were "getting around" the Uncertainty Principle. If I dig up the link, I'll post it.
The speed of light, or any other EM wave is a function of the dielectric permittivity, and the magnetic permeability of the surrounding medium. These values are easily measured for free space, which is what we are really interested in anyway.
As for building theories around something that doesn’t exist, there is simply no way around that. Quantum mechanics is built around mathematical models and observations that are themselves unverifiable in the context of some larger truth.
This in no way invalidates the model since in this respect it is similar to everything generated by science. Science itself is based on a fundamentally flawed logic argument, and as such can NEVER deal in absolute truths. It is, however, exceptionally good at generating useful results.
Since it can only deliver useful results and not absolute truth, any theory that can continue to generate useful results is itself useful. By insisting on a “perfect” theory you are in fact searching for truth, and this is something science cannot provide.
The issue I had with the things Ilkpc was saying. He seemed to feel that because quantum mechanics could, (with great difficulty) explain most of the things that relativity explains (with relative ease) that there was no further need for relativity. While I do not dispute that QM has surpassed relativity in accuracy, in many areas, including some most of the things discussed here, it is still not as useful.
For myself, I’m an engineer, not a physicist or a philosopher. I could care less whether a theory is true or even valid. All I care about is if it works for what I am trying to do at the time. If more then one model works then I take the simplest one, it as easy as that. Given that no scientific theory can be said to be true this is by far the best approach to take IMO.
By way of a quick explanation of what I am referring to:
The scientific method works as follows. Make observations, from those observations come up with a hypothesis that explains them. Use the theory to make meaningful predictions. Evaluate those predictions through experimentation and measurement. If discrepancies are found modify the hypothesis to fit the results. Once you no longer have discrepancies the hypothesis becomes a theory.
The flaw in this method is that to prove something using it you would have to observe literally everything and conduct every possible experiment. Since this is not possible, anything generated by the scientific method can never be stronger then a theory. Science can never give you truth, and anyone seriously involved in science should always keep in the back of his or her minds.
It is also why I find it amusing when someone says something is only a theory. A theory is the strongest statement you can ever make in science. By saying something is “only a theory” you call into question everything that science generates. Do you disregard the fact that computers exist because the science they are based on is “only a theory”? Science is not perfect, but it produces results far better then any other search for knowledge man has ever undertaken.
BTW the uncertainty principle really only states that you cannot know more then a certain amount about the position and action of a given particle. The error in position multiplied (IIRC) by the error in velocity must at all times be larger then some minimum value. There are also some other spin offs like not being able to know time and frequency exactly.
The fact that measurement effects outcome is a consequence of this. Since the total error has a minimum value, if you measure either property too exactly you MUST loose some information about the other. In any experiment you conduct the behavior of the second property therefore must change if you measure the first to exactly.
We are in agreement Moridin. My point about Einstein was that he was searching for a unifying theory, so absolutes are critical here. It is beyond argument that the theories of relativity are useful. As you stated, it doesn't mesh at all with QM though which is very important if you are working in theoretical physics.
I never said that the NEC experiments (peer reviewed BTW, not a bunch of quacks) violated relativity, nor did those scientists. I even mentioned that it was waves that were propagated superluminally. I was using it to point out that the medium the light travels in is very important (a complex medium in the NEC experiment). It's a damned interesting experiment nonetheless.
Ah, I see the mis-communication now. I re-read my post and I did say "theories" when what I meant was "unification theories".
Sorry for the confusion :(
Just a picky little note here: We never insist on having no discrepancies before calling any particular model a scientific theory. Instead, a 'scientific theory' is meant to describe any existing body of observations - and accompanying set of modeling hypotheses - which consistently fit the accepted paradigm of thought in a given discipline at a given time.Quote:
Originally posted by Moridin
Once you no longer have discrepancies the hypothesis becomes a theory... Science can never give you truth...
Historically, there has never existed a scientific theory which did not simultaneously have several known and confirmed anomalies at the particular time it was in fashion. Such discrepancies are not only unavoidable, they are usually assumed in advance to exist, by virtue of science itself being an entirely empirical (and thus experimental) endeavor. There are always discrepancies.
While no scientific theory can ever be proven, they are nevertheless considered disproven when 1)the volume of known discrepancies becomes unacceptable, and 2)a reasonable working alternative model is found. When this happens, the old bodies of knowledge are still called theories though (albeit "old" or "outdated" ones).
Because of this, there really is no flaw in the logic of the scientific method, only a focus on experimental rather than on purely intellectual discovery methods. Any quest for 'no discrepancies' would imply a truth discovery - and since truth is not a subject of science, there isn't a 'no discrepancies' requirement before calling any given model a scientific theory.
Again, just being picky here! It seemed especially relevant in this discussion though... :cool:
russ_waters:
IMO, religion is a set of beliefs that you live by. Would you agree with this? I believe that everyone has a religion. To some people, atheism is a religion. To some people nationalism is a religion. To some people, Communism is a religion. Thus, you can't say that religion causes science to not progress. People cause science not to progress, not religion, since everyone has different beliefs.
here is how to get a 1986 ford taurus going the speed of light: http://www.tweak3d.net/tweak/taurus/
Yeah, elimc, I'll buy that. Its people's REACTION to and USE of religion that causes them to hold back science. I don't see that as being more than a semantic difference between what I said, but either way I understand what you are saying and agree.
Can somebody explain the right hand rule of angular acceleration? (Not the right hand and left hand rules of electric fields) What does it mean that the thrust is always toward you with counter clockwise rotation?
It was my understanding that this is a somewhat arbitrary way of defining positive and negative for the angular acceleration vecor. I'm not positive about that though. I just accepted it and used it when I needed to.