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Farsight

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Everything posted by Farsight

  1. You're actually touching the water rather than the wave. That might sound like splitting hairs, but the distinction is important. You aren't touching a seismic wave if you touch the ground. You're touching the ground. The ground is shaking. You can feel it shaking, but you aren't touching "the shaking", which is what the wave is. Not necessarily. Take a look at refraction. Who says there's a single interaction point? Electrons have a wave nature too. See for example hyperphysics and electron diffraction.
  2. Here's something I wrote down a while back: Time exists like heat exists, being an emergent property of motion. It's a cumulative measure of motion used in the relative measure of motion compared to the motion of light, and the only motion is through space. So time has no length, time doesn't flow, and we don't travel through it. I used the word motion rather than change, but it's the same general idea. And it isn't something new. Actually it dates back a couple of thousand years, have a google on it. Also check out presentism and A World Without Time: The Forgotten Legacy of Godel and Einstein and Time is Change by Amrit Sorli. Here's a snippet from the latter: The doubt that "space-time" is the ultimate arena of the universe was raised by Dirac and recently by Julian Barbour: "On a beautiful October afternoon in 1936 I ravelled to the Bavarian Alps with a student friend, Jurgen. We planned to spend the night in a hut and climb to the peak of Watzmann at down next day. On the train, I read an article about Dirac's attempt to unify Einstein's theory of relativity with quantum theory. A single sentence in it was to transform my life: "This result has let me to doubt how fundamental the four-dimensional requirement in physics is". In other words Dirac was doubting that most wonderful creation of twentieth-century physics: the fusion of space and time into space-time."(6) Agreed. Nobody can, Raja. But celebrity "physicists" will doubtless carry on talking about time travel and similar woo.
  3. Questionposter: think of the photon as a wave, then think of a seismic wave. You can't "touch" a seismic wave, but you can feel it. That means you're interacting with it. But a seismic wave isn't some "whole thing" like a billiard ball, it's just a wave. You can interact with it briefly before I pull you up on a rope and get you back into the helicopter. Or you might have placed a little accelerometer on the ground. It has scant effect on the seismic wave. When it comes to photons there's something called "weak measurement" that's a bit like this. See The secret lives of photons revealed, a physicsworld article.
  4. I think there are some aspects of what you're saying that are right, but that you go too far with certain things and they undermine everything you say. Go and look at A World Without Time: The Forgotten Legacy of Godel and Einstein. Time doesn't slow down, clocks clock up local motion, not "the flow of time". It doesn't matter whether it's a mechanical clock, a quartz clock, or an atomic clock, that's what clocks do. So when a clock slows down, that local motion is occuring at a reduced rate. That's all there is to it. If you travel out and back through space your rate of local motion is reduced because of your motion through space. It's pretty obvious in the parallel-mirror light clock example wherein the Lorentz factor is derived from Pythagoras' theorem. The hypotenuse is the light path of length 1 because we're using natural units, the base is your speed as a fraction of c, and the height is the Lorentz factor, wherein there's a reciprocal to distinguish time dilation from length contraction. What you seem to be missing in your presentation is the significance of pair production. Matter, such as an electron is quite literally created from light, in a lab. And an electron exhibits spin angular momentum and magnetic dipole moment. The Einstein-de Haas effect then demonstrates that spin angular momentum is of the same nature as classical angular momentum. So there's something going round and round in there, and it ain't cheese. Now think about why an electron can't go faster than light.
  5. Good stuff. No. The typical picture you see of a "dent" shows space-time, not space. Apply your clock thinking above to a parallel-mirror light clock. When it ticks slower it isn't because there's "a dent in space", but because space is different there. No. Like Swanson said, it's gravitational potential that relates to time dilation. The force of gravity at some location depends upon the local slope of gravitational potential at that location. Time doesn't affect a quartz crystal vibrating. A concentration of energy does. It "conditions the surrounding space". It alters it, and motion through it. Clocks clock up that motion, and when they go slower, we call it time dilation. Photons don't have mass, but it isn't mass per se that causes gravity, it's energy. If you trap a photon in a mirror-box you increase the mass of that system, and the result is more gravity, but the photon causes gravity whether it's in the box or not. Note however that you can't practically measure it - after all, a huge concentration of energy like a star causes only a slight effect. Different-energy photons travel at the same speed because that's the way space is. Think of photons as waves or pulses, not billiard-ball particles.
  6. It was in a previous post of his. Of course it can. But stop nitpicking, Swanson. Go look at the photoelectric effect or something. Apologies. Fixed.
  7. That's back to front. The fields and particles depend on "how the energy is arranged". You used the word configuration yourself. Now test it against low-energy proton-antiproton annihilation to gamma photons. You started with quarks and gluons and the strong force plus electromagnetism, you maybe saw some residual-strong-force pions for a nanosecond, then you finished up with electromagnetic photons. The arrangement of the fields and particles has changed beyond recognition. But energy was conserved. See the second paragraph of this post by Cygnus on the original thread? Now look again at my post responding to what energy is: http://www.scienceforums.net/topic/59122-energy/page__pid__621381#entry621381 It's real enough, think it through. And the photon truly vanishes in pair production when the electron and positron fly apart. And when you decelerate an electron you still have an electron, but now you've got a photon too. He meant what he said. Matter is made out of energy. And photons aren't matter. I'm not worried about what Einstein formulated and calculated, because Does the Inertia of a Body Depend upon its Energy-Content? is straightforward. But I am worried about that 100+ years. Physics has stalled and funding is under threat (here's the latest), some understanding seems to have been lost, and we see unfounded speculations and myths promoted as bona-fide physics whilst real bona-fide physics struggles for attention. When there's no motion. It's an early-universe / black hole thing. Don't worry about it.
  8. Something else. I take my cue from A Zeptospace Odyssey: A Journey into the Physics of the LHC by Gian Francesco Giudice. He's a physicist at CERN with a hundred-plus papers to his name. He talks about the Higgs sector on pages 173 through 175. If you don't have this book you can find it on amazon and do a search-inside on "Higgs sector". He starts by saying: “The most inappropriate name ever given to the Higgs boson is 'The God particle'. The name gives the impression that the Higgs boson is the central particle of the Standard Model, governing its structure. But this is very far from the truth.” On page 174 he says: “Unlike the rest of the theory, the Higgs sector is rather arbitrary, and its form is not dictated by any deep fundamental principle. For this reason its structure looks frighteningly ad-hoc". He also says "It is sometimes said that the discovery of the Higgs boson will explain the mystery of the origin of mass. This statement requires a good deal of qualification.” He gives a good explanation, and finishes by saying: “In summary, the Higgs mechanism accounts for about 1 per cent of the mass of ordinary matter, and for only 0.2 per cent of the mass of the universe. This is not nearly enough to justify the claim of explaining the origin of mass.” As for SUSY, see Reality check at the LHC.
  9. Alexander: see A World Without Time: The Forgotten Legacy of Godel and Einstein along with The Other Meaning of Special Relativity by Robert Close. What you're proposing here doesn't sound all that different to special relativity to me. You put the emphasis on motion rather than time, but I'm confident Einstein would be happy with that if he was still around. NB: I'm afraid you're wrong about relativistic dilation time, which today has not been experimentally proved.
  10. You will arrive at a situation where you have no discernible photon energy left. The wavelength reduces further and further until it's no longer measurable. You don't, Swanson. You might think you do, but the mathematical physics you think of as standard pays insufficient regard to experimental physics, and rather glosses over E=mc² wherein Einstein said "All matter is made of energy". Pair production is the experimental evidence that supports this. The important point to appreciate is that you can employ a photon to make electrons move, and you can also employ a photon to actually make an electron. And a positron of course. In typical pair production the input photon is more than 1022keV so the electron and positron fly apart -you've used a photon to make an electron, and make it move too. Momentum isn't something distinct from energy, which is why we talk of energy-momentum. Energy is a "distance-based" scalar measure of energy-momentum rather than a "time-based" vector measure. Hence E=hf and p=hf/c, and we divide by c, distance over time, to go from one measure to the other. You cannot reduce the energy of that scattered photon without reducing its momentum by a commensurate amount. Hence we usually refer to photon just energy. Or at least, I do. You might prefer to say that the photon is an action configuration and refer to polarization, which is fine by me. Or you might prefer to say the photon is an elementary excitation of the quantized electromagnetic field. I wouldn't disagree. But I'd still point to Compton scattering and pair production to show that the photon is as close to pure energy as we can get in everyday physics. Think of it this way: a photon's energy is a vital property that makes it the thing that it is. It isn't like the kinetic energy of an electron. Take that away, and you're still left with an electron. Take away the photon energy, and you don't have a photon any more. NB: as you're aware you can take away the electron kinetic energy via Inverse Compton scattering. Or you can use a synchroton. See wiki and note this bit "Electrons traversing the periodic magnet structure are forced to undergo oscillations and thus to radiate energy". They radiate energy. Take it at face value.
  11. ajb: a "property of the configuration" is reasonable, but that just defers the question to configuration of what? I think a useful phenomena to examine here is Compton Scattering. This is from the hyperphysics website, which I think is very good: The photon gives the target electron a "kick", and is reduced in energy. The electron acquires kinetic energy and moves. If you then repeat this with the scattered photon, you tend towards a situation where you have no photon left. All you have instead is electrons that weren't moving and now are. The photon has essentially been converted into kinetic energy. Hence I think "photons are pure energy" is more reasonable than you do.
  12. Farsight

    Energy

    questionposter: energy is a physical thing, something very real, but it isn't something tangible. I suppose a photon is pretty much "pure energy", but you can't hold a light beam in the palm of your hand. And yet we can make matter out of photons. Check out pair production and the inverse process, annihilation: (From http://outreach.atnf.csiro.au/education/senior/cosmicengine/bigbang.html) You're made out of matter, so you're made out of energy. And then it is tangible. The important thing is this: you aren't made out of anything else. And you can't create or destroy energy, it's truly fundamental, more fundamental than electrons or quarks. And like I said, it is real: if you raise a brick you add energy to that brick, and as a result, the mass of that brick increases by virtue of E=mc². It's too slight to actually measure, but that brick gets heavier. As to what energy is, that's a bit trickier. If everything is made of energy, it isn't easy to say what it is, because you'd be defining it in terms of something made from it. But there's maybe a clue at the back of Beyond space-time: Welcome to phase space, a recent New Scientist article: "It has been obvious for a long time that the separation between space-time and energy-momentum is misleading when dealing with quantum gravity," says physicist João Magueijo of Imperial College London. As it happens I'm not a fan of quantum gravity, at least not the way it's usually described, so I focus on It has been obvious for a long time that the separation between space-time and energy-momentum is misleading. So in a nutshell I'd say "energy is space". Sounds strange I know, but think about an electromagnetic wave. It's a wave in space that conveys energy. People usually describe it as an electromagnetic field-variation, but when you ferret around wondering what a field is, you come across Einstein talking about the history of field theory in 1929. He talks about "structures in space". And you also come across displacement current. So at some deep profound level, I'd say an electromagnetic wave really is a wave in space. It's space waving. Freezeframe a wave and you'd see a bulge. So how do you make space bulge? You shove some more space in it. Something like that. But hey, don't ask me what space is.
  13. I'm afraid the graviton as generally presented is a myth. It's one of those hypothetical things which have been advocated in certain quarters for decades, for which there is no evidence whatsover. Ahhhh, some will say, but you can't prove it doesn't exist. To which you should shrug and say you can't prove that fairies don't exist either. The graviton is put up as the equivalent of the photon, as something that makes gravity "work", and that's a myth too. Because photons don't make electromagnetism work. Some people will claim that virtual photons make electromagnetism work, but look closely and you appreciate that there are no actual particles flying back and forth making that balloon cling to your curtains. Magnets don't shine, and cavorite doesn't exist. Because those virtual particles are virtual. That means they aren't real, not that they have a short lifetime. Take a look at the wiki article on near and far field. Pay close attention to the quantum field theory view. What it says is near field effects are due to a mixture of real and virtual photons. Says who? It's the other way round. The near field is also called the evanescent wave. It's something real, you can use it to charge up your mobile phone. But that coupling is a field effect, or a standing wave effect if you prefer, not particles rattling back and forth. A better way to say it is the evescent wave is the reality that underlies virtual photons. See Evanescent modes are virtual photons for more. Think about what a photon is. It's an electromagnetic field variation, maybe 1500m long, zipping through space at c. If you've got a +1022keV photon, you can use it to make an electron and a positron, via pair production. The electron has an electromagnetic field, which you've just made from a photon, and you can can trap that electron in an orbital around a proton. People tend to say it remains trapped because of messenger particles, virtual photons being exchanged between the electron and the proton. But there aren't any photons of any kind rattling back and forth. It's just field, made from field variation. There aren't any other field variations rattling back and forth. In the same vein the gravitational field is just field, and there are no gravitons or virtual gravitons rattling back and forth either. You can of course think of the earth's gravitational field as one big graviton. That would be like the evanescent wave, which is rather like half a photon that isn't going anywhere, a bit like the bow wave of a bridge pier. Or you can think of a gravitational wave as one big graviton. There's not so much of a problem with that, because close-orbiting neutron stars will lose energy, and it's got to go somewhere. The gravitational wave is then like a photon. It's going somewhere, and doing it fast. But in itself, it isn't made of tiny little particles, just as an electromagnetic wave isn't. Just a a photon isn't, and just like the earth's gravitational field isn't.
  14. No. If the force you felt were due to the other objects in the universe, these forces would have to result from instantaneous action at a distance. That's magic. It doesn't work like that. No. No, it wouldn't simply appear as if the ball was spinning around you. You'd feel your own rotation, and you'd feel dizzy. And no, the ball wouldn't be pulled in toward you. No. Again that demands instantaneous action at a distance. i An "absolute" frame of reference like the CMBR just gives you a way of determining your motion through the universe, which is as absolute as it things can get. But you don't feel inertia because of the CMBR.
  15. It's an electromagnetic wave Swanson. There is no charged particle present. But the field varies, so there is a current. It isn't conduction current. It's a displacement current.
  16. Because I'm talking about an electromagnetic wave here. See this alternative picture. Forget about the magnetic field variation because it's an electromagnetic field variation, and consider one wavelength starting from the origin rather than the peak: Thanks for your feedback. I'm scratching my head about them. I don't actually understand what the potentials are. The wiki page on four-potential defines it as: [math]A^{\alpha} = \left(\frac{\phi}{c}, \mathbf A \right) \qquad \left(A^{\alpha} = ( \phi, \mathbf A)\right)[/math] ..in which "φ is the electrical potential, and A is the magnetic potential, a vector potential." I'm confused about the A mentioned in the AB effect. Looking at the photon in terms of displacement current says the displacement is at a maximum midway along the sinusoidal wavelength where the electromagnetic field variation is zero. That's like the AB effect. This midway point is where the potential is at a maximum, which means the sinusoidal waveform is telling you the slope of the potential. Ever read Ehrenberg and Siday's The Refractive Index in Electron Optics and the Principles of Dynamics? They wrote it in 1949, it's all classical, and figure 3 shows what's now known as the Aharonov-Bohm effect. I found this paper interesting too: http://arxiv.org/abs/quant-ph/0604169. Not that I understand much of it.
  17. The reason I'm asking is related to the Aharonov-Bohm effect and electromagnetic four-potential. And it's related to the OP, particularly since Widdekind has been talking about this elsewhere. Take a look at http://www.chem.yale.edu/~chem125/125/xray/diffract.html and this depiction of an electromagnetic wave: Look at one complete wavelength, starting from the left. There's an electromagnetic field variation here, but no charged particle present. So there has to be some sort of current, and it isn't conduction current. So surely it's displacement current? Orthogonal to the propagation direction, and giving the polarization axis? Assuming a plane-polarized light wave, does the sinusoidal waveform denote the strength of this current? It increases to a positive peak, but continues "flowing upwards" weaker and weaker as the waveform returns to zero. If so the displacement current presumably then turns downwards, reaching a peak strength at the negative sinusoidal peak before weakening on the return to zero. So halfway along the waveform, where the electromagnetic field is zero, the displacement is at a peak, and the photon is essentially a pulse, as per http://arxiv.org/abs/0803.2596. In the Aharonov-Bohm effect there's no electric or magnetic field outside the solenoid, but we know there's something there. Is this the same sort of thing, and is the evanescent wave a standing displacement? Clearing up those As and Vs would help here.
  18. Hi Widdekind, Bob. Can either of you explain the difference between A and V?
  19. No. I'm countering the position you did put forth, that you are traveling forward [in time] at one second per second. You aren't , because you aren't travelling in time at all. It's just a figure of speech. The science-fictional stasis box and film frames and the freezer hopefully make this clear, and hopefully make it clear that time travel is science fiction too.
  20. There's no issue with the SR time dilation equation, IME, or with the experimental proof. Time dilation is very real. But "the passage of time" is another figure of speech. Time doesn't actually "pass" in the sense that time literally moves or we literally move through it. Things move through space, and we use this to derive the time dimension. But it's a dimension of measure rather than one that offers freedom of movement. Yes, the macroscopic motion that your wristwatch experienced while travelling through space caused it to run a tiny bit slower. The reading on the face is reduced, and we say that less time elapsed. But all that really happened is that the cogs and sprockets within your watch moved at a reduced rate in what you'd call your local space or frame, because you were moving fast through the universe. The wikipedia article on time dilation has a section showing how the time dilation equation is derived from Pythagoras' theorem. Consider the hypotenuse of a right-angled triangle as the light path, and the base as your speed v as a fraction of c. Using natural units where c=1, the height √(1-v²/c²) gives the Lorentz factor, where we use a reciprocal because length contraction has the opposite sense to time dilation. If you're travelling at .99c the height of the triangle is .141 and the Lorentz factor is 7.089. In round numbers you'd experience a seventh of the time, and to you space would appear to be length-contracted sevenfold.
  21. It's a figure of speech swanson. You aren't really "travelling" into the future at one second per second. All: Hold your hands up. See that gap between them? That's a space, and you can see it’s there. Now waggle those hands. That's motion, and you can see that’s there too. But can you see time? No. Can you see time flowing? No. Can you see any travelling through time? No. There’s no actual scientific evidence for time flowing or time travel. Time travel is science fiction, and it’s going to stay that way forever because travelling back in time is impossible. Not because wormholes are tricky, or because closed timelike curves are hard to handle. It’s impossible because we don’t even travel forward in time. To understand this, think about a stasis box. That’s science fiction too. It’s the "ultimate refrigerator". No motion occurs inside the box, so when I put you inside, electromagnetic phenomena don’t propagate, and absolutely nothing happens. So you can’t see, you can’t hear, and you can’t even think. Hence when I open the door 5 years later, to you it’s like I opened the door just as soon as I closed it. And get this: you “travelled” to the future by not moving at all. Instead everything else did. And that motion wasn’t through time, and it wasn’t through spacetime, it was through space. You can't travel through spacetime because it's an "all time view". It's like taking a film of a red ball travelling across a room, then cutting the film up into individual frames and stacking them into a vertical pile. You can see a red streak in there, which is effectively the ball's world-line. But the ball isn't moving along it. Hence there's no actual travel through spacetime, and nor is there any actual travel through time. Anyhow, that the stasis box is science fiction, but don’t forget, we can freeze embryos now. So “in the future” maybe we’ll be able to freeze an adult. Then you could “travel” to the future by stepping into a freezer. But you aren’t really travelling. You aren’t moving. Everything else is.
  22. There is no magical mystical action-at-a-distance. Even Newton knew that over three hundred years ago. In a letter to Richard Bentley on 25 February 1692, he said: “That gravity should be innate, inherent, and essential to matter, so that one body may act upon another at a distance through a vacuum, without the mediation of anything else, by and through which their action and force may be conveyed from one to another, is to me so great an absurdity that I believe no man who has in philosophical matters a competent faculty of thinking can ever fall into it”. Once you remove action-at-a-distance, what you're left with is this: a field is a region of space where the properties of space vary, and the interaction of a particle with this space results in altered motion. You might prefer to say it some other way, and you might want to discuss the causative body or particle. But once you drop that magical mysterious action-at-a-distance, I think it always comes back to the same in the end: a field is a region of inhomogeneous space.
  23. IMHO it looks something like a "spindizzy" would look like. See http://en.wikipedia.org/wiki/Spindizzy. Years back before I got into physics, I wrote a science fiction story called Spindizzy featuring a flying car with washing machines for wheels. But it's just science fiction. I don't know of any explanation/theory on the web, and I don't know how it could possibly not fall down. Besides, I've got an electric gyroscope, and once it's spinning at full speed it's extremely difficult to rotate it in an orthogonal direction. As far as I know, to make an object not fall down, you need to be able to generate an artificial gravitational field above the object to balance the earth's gravitational field. Then it still takes energy to go up.
  24. We should talk about time properly Swanson, and what clocks actually measure. Neutrinos have nothing to do with temperature. But some people claim that they can influence decay rates. I'll ask around and see if anybody has conducted any tests, say at ArgoNeuT.
  25. A pleasure, abhilash. When it comes to relativity, do bear in mind Minkowski’s Space and Time , and look at what he said about two pages from the end: "Then in the description of the field produced by the electron we see that the separation of the field into electric and magnetic force is a relative one with regard to the underlying time axis; the most perspicious way of describing the two forces together is on a certain analogy with the wrench in mechanics, though the analogy is not complete". This is echoed in Maxwell's On Physical Lines of Force where he said: "A motion of translation along an axis cannot produce a rotation about that axis unless it meets with some special mechanism, like that of a screw." By the way, is the current going the wrong way in wire-section AB in your figure 3? I'm not sure if this would change the outcome. Perhaps it would be simpler if you replaced wire-section AB with an electron beam? Meanwhile do read up on the Ehrenberg and Siday paper and the Aharanov-Bohm effect wherein "the electromagnetic potential A is seen as being more fundamental or "real"; the E and B fields can be derived from the potential A, but the potential can not be derived from the E and B fields."
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