A constant speed of light in all reference frames? Surely you can't be serious.
in [Relativity]
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From: mpalenik on 21 Feb 2010 17:28 On Feb 21, 4:57 pm, Ste <ste_ro...(a)hotmail.com> wrote: > On 21 Feb, 01:45, "Peter Webb" <webbfam...(a)DIESPAMDIEoptusnet.com.au> > wrote: > > > > > "Ste" <ste_ro...(a)hotmail.com> wrote in message > > > > On 20 Feb, 05:27, "Peter Webb" <webbfam...(a)DIESPAMDIEoptusnet.com.au> > > > wrote: > > >> If you're suggesting that it's improbable that a theory could work not > > >> because its premises were correct, but because it simply promoted > > >> correct behaviours, then wonders why religion has fared so well. In > > >> any event, I'm willing to accept Feynman's argument, basically that QM > > >> amounts to a workable mathematical model, and makes no claim to any > > >> truth more fundamental than that. > > > >> ________________________________ > > >> The whole of physics is like that, not just QM. Physics just gives us the > > >> eqns by which the universe functions. It does not make claim to any more > > >> truths fundamental than the eqns; the rest is just philosophy. > > > >> Your problem of course is that you don't understand the eqns, so you > > >> don't > > >> understand physics. > > > > On the contrary, my problem is that physics seems to have dispensed > > > with the physical. Yet it is the physical, as opposed to the > > > mathematical, that I am interested in. That is, the qualitative > > > physical concepts - what I've referred to as an explanation at the > > > the "practical-mechanical" level - that would seem to me to > > > distinguish physics from maths are largely absent, and indeed seem to > > > be systematically deprecated and devalued. > > > You should look up, and learn, Minkowski space time. This gives a > > practical/mechanical explanation of SR that most physicists find very easy > > to use and understand. However even simple explanantions do involve high > > school mathematics. Like I said, it can only be "dumbed-down" so far. > > Peter, will you please stop treating me as an idiot, as though I > somehow don't understand the nature of Minkowski spacetime. You don't. What makes it Minkowski spacetime? How do space and time behave under rotation in a way that is different from a rotation in non-Minkowskian spacetime? What shape is a curve made up of points equidistant from the origin? Why is it different from regular, euclidean space? What is it about a moving object that makes it look like it's rotated in a 4 dimensional, Minkowskian manifold?
From: mpalenik on 21 Feb 2010 17:37 On Feb 21, 4:57 pm, Ste <ste_ro...(a)hotmail.com> wrote: > > and the authority of this group is > implicitly invoked on yet another occasion. This group has no "authority" on anything whatsoever. This is not where scientists come to have serious scientific discussions. This group is not mainly composed of real scientists (although the ones who are are easy to pick out). This group does not represent a significant fraction of the people who have studied physics. This group should not be used as a source to pull citations from or learn actual academic material, since none of it is peer reviewed or edited. I have no idea why most of the people who post here do so. I even asked PD about this a while back. For me, it's kind of theraputic, after grading dozens of papers where freshman students have written "no polarization" and then drawn a picture of polarized atoms, or listed "the force the boy exherts on the mother is smaller than the force the mother exherts on the boy" as a reason for why a mother who pushes a boy on ice-skates doesn't move, while the boy does. You can't call them stupid, although here, there is no such rule when someone says something so mind-bogglingly sputid. On the other hand, at least, freshman physics students are capable of learning, whereas for some miraculous reason, 90% of the people here seem to be stuck in perpetual, unwavering ignorance.
From: mpalenik on 21 Feb 2010 18:10 On Feb 21, 4:57 pm, Ste <ste_ro...(a)hotmail.com> wrote: > > If we were to extrapolate a trend from history, then physics has not > yet given us a single equation which describes how the universe > functions. It has given us some rules of thumb and some cumbersome > approximations. This just further illustrates that you don't understand how physics actually works. The history of physics isn't a series of blunders that we've thrown out as we get better and better equations, hampered by our belief in the old equations. Rather, physics at just about every point in time since the renaissance has been a journey from very specific to more general rules--criteria by which any new physics must be constrained. For example, Kepler, while not really a physicist per-se, devised descriptions of the elliptical orbits that planets must follow. Newton, then, discovered that this is a special case of the conservation of angular momentum, which is a much more general principle--however, conservation of angular momentum MUST be able to reproduce the elliptical orbits of planets, or else it is wrong. Kepler's rules constrained Newton's theories. Special relativity then changed Newton's laws, a bit. The basic principles, like F = dp/dt remained, but Special relativity says that space and time must transform differently than they do in Newtonian mechanics. However, Newtonian mechanics is still a special case of special relativity--as the speed of an object approaches zero, the laws begin to reproduce Newton's laws. Newton's laws, in this way, constrain Special Relativity. Because if it did *NOT* reproduce Newton's laws at low speeds, it would be wrong. General relativity came along and it turns out that special relativity only works as a limiting case of general relativity, specifically, when there is no mass or energy present. As the amount of mass and energy present goes to zero, general relativity reproduces special relativity. If it could not do this, it would be wrong. Any new physics must be able to reproduce the old physics in the regimes in which it has been tested. Any new theory that cannot do so is necessarily wrong because it has already been ruled out by experiment. There's no way to know whether at some higher energy or smaller distance than we've observed the laws of physics actually are different than what we believe. But even so, these new laws must reduce to the old ones at lower energies and larger distances. And if there is some new, more fundimental physics at a different scale, there's always a nobel prize, or at least several publications in it for anyone who can find this. In order to have a new working theory, however, you must be able to 1) make predictions that differ from those of the old theories and 2) show that those predictions match either a new experiment or a previously unexplained experiment.
From: mpalenik on 21 Feb 2010 18:37 On Feb 19, 11:28 pm, Ste <ste_ro...(a)hotmail.com> wrote: > On 19 Feb, 01:53, mpalenik <markpale...(a)gmail.com> wrote: > > > > > On Feb 18, 4:12 pm, Ste <ste_ro...(a)hotmail.com> wrote: > > > > On 18 Feb, 16:35, mpalenik <markpale...(a)gmail.com> wrote: > > > > > On Feb 18, 9:43 am, Ste <ste_ro...(a)hotmail.com> wrote: > > > > > > I'm confused Mark. > > > > > > My position is that someone must hold a priori that alternate > > > > > dimensions are a real possibility, in order to hold that any theory > > > > > that employs alternate dimensions is credible. Some here do hold that > > > > > alternate dimensions are a real possibility, so of course they hold > > > > > theories that employ them as credible. > > > > > > I don't hold that alternate dimensions are a real possibility, so of > > > > > course I don't accept that theories that employ them are credible.. > > > > > The problem is, you act like everybody in this group went into physics > > > > classes knowing and believing everything that was taught in the > > > > physics classes. > > > > No, I'm basically saying that the only people who came *out* of those > > > classes, and went into theoretical or experimental physics, are the > > > people who by the end believed any of that nonsense. > > > So, you don't think educated people could possibly understand > > something you don't. Interesting. > > That's not what I said. That's exactly what you implied--that since you don't understand it, it's nonsense, and it couldn't possibly be that the education has actually allowed people to understand something that still seems like nonsense after your one month of "thinking really hard about it."
From: mpalenik on 21 Feb 2010 18:41
On Feb 19, 11:25 pm, Ste <ste_ro...(a)hotmail.com> wrote: > On 18 Feb, 21:48, PD <thedraperfam...(a)gmail.com> wrote: > >I'm willing to accept Feynman's argument, basically that QM > amounts to a workable mathematical model, and makes no claim to any > truth more fundamental than that. Feynman said nothing of the sort. What you're probably thinking of is how the Feynman diagrams of his quantum field theory do not represent actual physical occurances (although they appear to) but are simply convenient ways of breaking the mathematical problem up into steps. The solution certianly is supposed to represent a physical reality, but the Feynman diagrams are merely mathematical tools for getting that solution. |