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Everything posted by timo
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I´d like to echo that statement. The baseline of some of the points you (sunspot) raise are valid questions that everyone trying to undertstand relativity should sooner or later ask himself. What is a bit disturbing is your attitude to assume that you found a huge gap in the knowledge of mankind instead of being a bit more humble and start with assuming you found a gap in your personal knowledge/understanding.
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I don´t get your link. You have formed a news team about a new fuel only available in the UK ?
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No. That would be exactly contrary to what I said in the part of my post that you quoted. I said: In 4D-spacetime, "taking the same path from A to B" includes having the same velocity at all points (a point is a place with definite space AND time coordiante). If they have different masses and the same velocity, their kinetic energy is different (except for the case where they do not move in space). But they will experience the same time from A to B.
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Hi Ragib, welcome to SFN. Your statement about increasing mass might be irritating for some people in here. That is because we have a silent agreement to refer to the restmass when talking about mass and identify the remaining difference to the relativistic mass as kinetic energy. It has shown that an inconsistent usage of the term mass gives rise to a lot of unnessecary confusion. So it would be good that when posting you explicitely stated that you´re talking about the relativistic mass or even better if you adopted our terminoligy and use the invariant rest mass.
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Coincidence, Underlying Reason, it doesnt matter, Its pretty Amazing...
timo replied to Ragib's topic in Mathematics
Just take pen&paper and calculate it out: [math] \left(\frac{1+\sqrt{5}}{2}\right)^{-1} = \frac{2}{1+\sqrt{5}} = \frac{2}{1+\sqrt{5}} \cdot \frac{1-\sqrt{5}}{1-\sqrt{5}} = ... = \frac{1+\sqrt{5}}{2} -1 [/math] -
Imho the problems here start with very basic misunderstandings like: That´s pretty nonsaying since a) "negative special relativity" is a term you made up. Therefore SR does of course not account for it. b) Any real number squared is positive. Following your example I could claim that stairs can he only taken upwards since the difference in height squared is always positive. But for what I think your problem is: Velocity does NOT appear squared IN ALL equations used in relativity. Especially not in all entries of the Lorentz Transformations which are the rules for transforming between different coordinate systems: http://en.wikipedia.org/wiki/Lorentz_transformations EDIT: @[Thyco?]: Please refrain from posting if you have nothing to say which constructively adds to the thread.
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Strictly speaking, fields do not have a time measure. In the relativistic sense, time is either a length of a curve in spacetime ("eigentime") or a direction in spacetime (time coordinate). The former is an attribute of spacetime, the latter an attribute of a chosen frame of reference. None is an attribute of a field or particle. The term "time clock" is unknown to be, btw. I can only assume what you are speaking of (oh, and what other clocks than "time clocks" exist ?). The time experienced by a particle travelling from A to B (notice that when A and B have the same space coordinates but different times, this is still travelling from A to B in spacetime) solely depends on the path taken (see "eigentime" in above). Therefore, two unequal masses taking the same path will experience the same time difference from A to B.
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No. Let the relationship be [math] \vec F = \frac{m^2}{1 \text { kg}} \vec a[/math], for example. That clearly violates F=ma. Still, two unequal masses would not have the same acceleration when the same force works on them.
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It´s not consistent with the common way it´s seen. Normally, curvature of spacetime is related to intrinsic properties of it. Besides from that I don´t know if the "we embed spacetime in a 5D space"-approach leads to a working mathematical model, it also has the philosophical advantage that you don´t have to have something the universe lies in.
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I´ve seen that claim quite often. It´s just that I don´t understand it. Same is true for a year in geology. But I still know that 2005 came before 2006. A line (1D) is commonly believed to be made out of points (0D). Planck time would be an interval on the line not a point, anyways. You can multiply the Planck time by a finite number to get 1 second. But you cannot take a finite number of points to get a line of length 1 cm. No, not really.
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I´ve used Python a few years back and I found some old code snippet that might prove usefull to help you a bit: """ Create a fake "spiral galaxy" """ from scipy.xplt import * # STEERING CONSTANTS size = 150 # Size of the matrix # Part of the complex plane to be shown rMin, rMax = -0.578, -0.563 iMin, iMax = -0.569, -0.555 # => Stepsizes dr, di = (rMax-rMin)/size, (iMax-iMin)/size def RecursionDepth(c): z = 0.0+0.0j d = 0 while abs(z)<2: z = z**2+c d +=1 if (d>200): return d # print z, d, abs(z), c return d # Create Matrix M = zeros((size, size)) re = rMin for i in xrange(size): im = iMin for j in xrange(size): z = re+im*1j M[i, j] = RecursionDepth(z) im += di re += dr window(1) palette("heat.gp") M[0,0] = 300; pli(M) raw_input() winkill(1) I dunno if the scipy-package (scipy stands for "scientific python", I think) is widely used (i.e. if it´s in the distribution you downloaded) but one of your questions might be answered by above code even if you don´t have it: - You can set the type of a variable by giving it an appropriate value. So if you want an integer to equal one, you assign "x = 1", if it´s supposed to be a floating point variable, you assign "x = 1.0" and if it´s supposed to be a complex, you assign "x = 1.0+0.0j". Not completely sure if that´s what you wanted, though. For the other question: - Afaik, Python is a comeplete OOP programming language so you should be able to do anything you can do with other programming languages. I think even the 3D-engine Ogre3D has a Python version. I really enjoyed writing programs in Python and I think it´s quite a good language for a beginner (although I don´t know whether you are a beginner or not).
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I acutally did not read you first post in here. I posted a reply to your post #4 which you originally posted as a new thread. During the time it took me to write the reply, the thread was deleted and the post I wanted to reply to showed up here -> copy-pasted the answer here. I usually don´t participate in "what if [some thing most physicists believe to be true] were not true"-threads and I don´t really want to comment much on your post #1. But I can tell you why and what the problem with such threads/ideas is: When I assume some physical law not to be true, what about the other ones? Is it possible to change one physical law without altering the other ones (ususally the answer is "no")? How do the other laws have to change, then? Is there a clear rule for it or would a completely new set of laws be needed? If there´s a new set of rules needed, which one (people tend not to state this)? And if it could be any set of rules, then of course anything is possible. And then: Speculation about "what happens if anything is possible" seems pretty pointless to me. The energy required to accelerate an object of mass m from rest to a velocity v is [math] E = mc^2 \left( \frac{1}{\sqrt{1-v^2/c^2}} - 1 \right)[/math] according to special relativity. Therefore, the velocity you have attained with putting an energy E into the movement will be [math] v(E) = c \cdot \sqrt{1- \left( \frac{mc^2}{E+mc^2} \right)^2} [/math]. As you can hopefully see, for a mass greater than zero, the velocity will always be smaller than c, no matter how much energy you used to accelerate the particle. It´s less about being able to imagine something, it´s more about thinking pure imagination doesn´t make much sense. I think that true science requires the imaginations to turn into a coherent model which leads to verificable predictions of what nature is/behaves like, not into fantasies of what nature would be if it was different from what it appearently is.
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Yes. I am afraid I cannot comment on your ideas other than from the standpoint of current mainstream physics. If you go beyond that' date=' then ... well... to twist a quote from Futurama: "Everything is possible if you can only imagine it. That´s what being a scientist ... err.. magical elf is all about". EDIT: And as a matter of fact, imho that is exactly what you should expect in the relativity subforum of a science forum: An answer saying what relativity sais about the issue at hand. I wouldn´t see it as having travelled in time. Some others might. I never claimed E=mc² was an incorrect equation. It´s "massless particles" that can and do travel at lightspeed, which includes light. "Energy" really only is a property of a particle or a system of particles, no "entity" - regardless of what the terminoligy "lifeform made out of pure energy" in Star Treck suggests.
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Looks more like 2.6 seconds to me. And my bathroom is less than 10m from where I´m sitting right now. But at least we´ve proven that only Mr. Powell is able to beat the speed of light and only if it´s very urgent ....
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^^ Let´s hope that post (#4) is the same as the one in the thread that got deleted, as I replied on that one. Not really, but anyways: Which of course is not possible Basides that E=mc² seems inappropriate here, it´s validity is not limited to velocities near/at lightspeed (to some degree one could even say it´s only valid at zero velocity but that depends on what E=mc² is acutally supposed to mean). So if you say your mass becomes a form of energy, why wasn´t it before? Energy is a property of a particle. So that statement is equivalent to saying "only volume can travel at the speed of light". Below lightspeed I see little reason for that. At lightspeed ... well, you just can´t reach it . But wormholes are highly speculationary, anyways. They´re a blessing for science fiction, at least. I can´t comment here. I don´t understand it. You could have had this easier: Send a beam of light to the moon and reflect it back to your bathroom. If you´re quick and your sister/girlfriend/wife/daughter isn´t in, you have a good chance of being there faster than the light. But at least we have good reasons to believe it´s not possible. Sorry, but my english skills are not sufficient to decipher this. I suspect you´re asking if what you proposed makes sense? Physically: No, it doesn´t. I´d like to add that while those "perhaps we can break the lightspeed barrier by this or that exotic method"-ideas might be some fun, they´re not very likely to lead to any success. There´s been millions (rather hundreds of millions) of people having tried it. And not all of these millions were much less intelligent or well educated than you (where "you" does not nessecarily refer to mr. d but to anyone thinking "if only a smart guy like me approaches the problem, every known limit in physics will break down" - me, for example ).
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ln(5 x^4) = ln(5) + ln(x^4) Therefore if C=ln(5) you have your old func back.
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Perhaps not an unfair assumption but it seems it would violate special relativity. What happens when you go to another coordinate system where the old time-direction now is a mixture of a time- and space-direction? You get a mixture of discrete and continuous steps, at least in the naive form I am having in mind right now. Therefore you´d have a certain coodinate system which qualitatively differs from all others (namely by that there is no mixture of continuity and discontinuity in the time-coordinate). But of course we´re talking about extreme regions (small distances) which cannot be probed and it´s hypothetically possible that special relativity (or any other well-proven physical theory) won´t hold true in these regions. After all, that´s why people let their imaginations run loose there - less risk of being caught by hard facts. As for the discrete spacetime in general: In mainstream physics, spacetime is considered contiuous. Afaik, some approaches (namely lattice gauge theories) use a semi-discrete spacetime. By that, I mean doing a calculation in a discrete spacetime (to avoid problematic integrations, I´d guess) but take the limit of stepsize zero (-> continuous spacetime) for the final result. But I´m not even sure where I have this idea from .
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I think particles with a diameter of 5 Ampere actually can
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72% of all percentages given are made up out of thin air.
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No chance buddy, correcting that very equation is my territory . Besides, you should have some mercy with someone whose only fun in life is telling others that [math] \sqrt{a+b} \neq \sqrt{a} + \sqrt{b} [/math] .
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Nope. Just take a look at the units to see that E = pc, not pc². Looking at the units is an easy, powerful and usually underestimated quick check if an equation/statement makes any sense at all. In fact, it would also be a good idea for Alpha-137 to take a look at the units and reconsider if the speed of light really is an acceleration.
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Actually, it´s [math] E^2 = m^2c^4 + p^2c^2 [/math].
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I cannot really understand what good it is to start talking about acceleration and GR here. It is not asked for and also does not really seem to add much interesting effects here (except for the nessecary breaking of the "either one could be the inertial reference system"-symmetry). Taking into account acceleration does not lead to any qualitative changes (the time experienced for the travellers will always be smaller than the time experienced for the people left behind) and in the limit of an arbitrarily strong acceleration you´ll also get the same quantitative result. This can be understood if you calculate the time tau experienced for the people in the rocket as [math] \tau = \int_{t_0}^{t_1} \gamma(t)^{-1} dt [/math] where t is the time coordinate in the system of the people left behind and gamma is the Gamov factor due to current velocity which always is >=1. As a sidenote: I am not sure if there´s really an official definition saying that dealing with accelerating frames is GR. I´ve seen both: Statements saying that GR begins at the point at which you consider arbitrary coordinate systems (this includes dealing with acceleration and stands in contrast to the "normal" use of inertial coordiante systems only) and statements saying GR begins at the point where gravitity comes into play (the arbitrary coordinate trafos are a nessecary condition for dealing with it but both things are not completely equivalent).