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Photo Forum / Film Photography / 35 mm / November 2006FASTER THAN LIGHT TRAVEL NOW A FACT...
...over limited distances... http://www.space.com/scienceastronomy/astronomy/light_speed_000530.html Excerpt from the web page: "The situation is somewhat similar for faster-than-light experiments to date, Chiao said. The beams contain a mathematical entity, called modes -- the patterns by which the waves hang together -- that outpace light. But there is no physical entity that does so." What the heck is a mode (a la mode?) and if its just a mathematical entity how can it travel faster than light if it has no physical existence - how can the patterns of the light outpace the light itself and how/why are the two separate things? Is this "modality" some weird kind of perception changes existence quantum phenomenon? And, most importantly, does this mean I'll get back my 35mm SLR photos from the processor before I take them? ;-) > ...over limited distances... > [quoted text clipped - 15 lines] > And, most importantly, does this mean I'll get back my 35mm SLR photos > from the processor before I take them? ;-) This year you will get the pictures back before you take them. Last year you will get them back before you buy the camera.  SignatureMichael | "He's dead, Jim." > > ...over limited distances... > > [quoted text clipped - 20 lines] > -- > Michael | "He's dead, Jim." Yes, but if I have a Return Authorization Number can I get my money back (Minus a small re-stocking fee) next year's camera which I bought and didn't like but was within next year's 14 day trial return window? Why put off to next year what you can do today? "Tommorrow Never Knows"... Does it mean my next year's money is now in deflation mode or hyper-inflation mode or GoodYear blimp mode? > http://www.space.com/scienceastronomy/astronomy/light_speed_000530.html > What the heck is a mode (a la mode?) and if its just a mathematical > entity how can it travel faster than light if it has no physical > existence It can 'travel faster than light' precisely because it has no physical existence. As the web site says: "In one sense, it's accurate, ... in another, it's very misleading." Look up 'group velocity', there is an animation here: http://galileo.phys.virginia.edu/classes/109N/more_stuff/Applets/sines/GroupVelo city.html This is not anything new, for all I know it has been around since Newton ... SignatureNicholas O. Lindan, Cleveland, Ohio Darkroom Automation: F-Stop Timers, Enlarging Meters http://www.nolindan.com/da/index.htm n o lindan at ix dot netcom dot com > > http://www.space.com/scienceastronomy/astronomy/light_speed_000530.html > > What the heck is a mode (a la mode?) and if its just a mathematical [quoted text clipped - 3 lines] > It can 'travel faster than light' precisely because it has no > physical existence. How could anything that doesn't exist have an speed at all since there is nothing there that can have any speed in the first place? > As the web site says: > [quoted text clipped - 7 lines] > This is not anything new, for all I know it has been around > since Newton ... Have read the explanation and still don't understand. Give me gravity any day, an apple falling on a head, now that's something I can understand, LOL :-) Not in this universe... > ...over limited distances... > [quoted text clipped - 15 lines] > And, most importantly, does this mean I'll get back my 35mm SLR photos > from the processor before I take them? ;-) > ...over limited distances... > [quoted text clipped - 12 lines] > and how/why are the two separate things? Is this "modality" some weird > kind of perception changes existence quantum phenomenon? The "flashlight" analogy was very apt. The angular rate of the beam is constant but at a point far enough along the beam the tangential velocity of the beam can be many-many times the speed of light ... but the photons are still radiating radially at the speed of light at that point. No information is conveyed tangentially, only radially. Cheers, Alan PS: Is that you Lewis? Signature-- r.p.e.35mm user resource: http://www.aliasimages.com/rpe35mmur.htm -- r.p.d.slr-systems: http://www.aliasimages.com/rpdslrsysur.htm -- [SI] gallery & rulz: http://www.pbase.com/shootin -- e-meil: Remove FreeLunch. > > ...over limited distances... > > [quoted text clipped - 18 lines] > the photons are still radiating radially at the speed of light at that > point. No information is conveyed tangentially, only radially. But the photons are still travelling _tangentially_ at the speed of light so doesn't that make their particles faster than the speed of light? > Cheers, > Alan > > PS: Is that you Lewis? No, just us sub-light photons :-) > -- > -- r.p.e.35mm user resource: http://www.aliasimages.com/rpe35mmur.htm > -- r.p.d.slr-systems: http://www.aliasimages.com/rpdslrsysur.htm > -- [SI] gallery & rulz: http://www.pbase.com/shootin > -- e-meil: Remove FreeLunch. >> > ...over limited distances... >> > [quoted text clipped - 24 lines] > light so doesn't that make their particles faster than the speed of > light? Not at all, and in fact, it's sophistry. We tend to think of a beam of light, such as the aforementioned spolight, as a constant, almost a solid. However, it's really a stream of photons progressing at their own pace. Realigning a very long beam, as in the comparative description in the article (though it was unclear whether the reporter or the scientist made this comparison) simply means that you have changed the target of the photons faster than they could travel between the targets on their own. But while you aimed at a new target before the photons had reached the old one, they're still on their way. So if that's the kind of thing they're actually talking about in this article, I can't help thinking, "Whoopee sh.t." I was wondering if the article was speaking of this, or a variation of it: http://www.straightdope.com/mailbag/mphasevel.html The mirror part doesn't sound like it, but the last part might be related. As it is, I'm not sure I really want light to go faster than light. I have enough trouble with reaching infinite mass while trying to catch it, I'm not going to like going beyond infinite mass. - Al. SignatureTo reply, insert dash in address to match domain below Online photo gallery at www.wading-in.net > >> > ...over limited distances... > >> > [quoted text clipped - 37 lines] > own. But while you aimed at a new target before the photons had reached > the old one, they're still on their way. I am confused, are you saying its all semantics and that the target is somehow being moved ?closer to the photons to make it appear those photons are travelling faster than light -- something like moving the finish line tape/mark to get a faster runner's track time/speed? > So if that's the kind of thing they're actually talking about in > this article, I can't help thinking, "Whoopee sh.t." LOL > I was wondering if the article was speaking of this, or a variation > of it: http://www.straightdope.com/mailbag/mphasevel.html Well, now I _finally_ understand how a packet of particles (say that 10 times faster than the speed of light ;-)) can _appear_ to travel faster than light. Thanks for the link. But what I don't understand is... "In a forthcoming article in the journal Nature, Dr. Lijun Wang and colleagues of NEC at Princeton will detail an experiment in which they accelerated light pulses to AT LEAST THREE HUNDRED TIMES c! Furthermore, Italian scientists at the National Research Council say they have pushed microwaves to 1.25c!" Is this more semantics/trickery or can I expect my microwavable pop corn to blast out of the bag at "Warp speed, Mr. Sulu!"? ;-) One time I got real sick and regurdgitated at warp factor 6 but we won't get into that here -- somewhere there are Einsteinian physicists with my egg sandwhich on their faces ;-) LOL > The mirror part doesn't sound like it, but the last part might be > related. > > As it is, I'm not sure I really want light to go faster than light. > I have enough trouble with reaching infinite mass while trying to catch > it, I'm not going to like going beyond infinite mass. Beyond the speed of light mass and weight start going down so by the time you hit warp factor two you are slimmed down to the point of becoming a weightless point, or, as, we like to put it in scientific terms -- "America's Top Model" -- or should that be "America's Top Modal" ;-) Past warp four you get a reversal yet again and you go from a point back to "infinite a.s" in which case you get "America's Top Couch Potato" ;-) > - Al. > > -- > To reply, insert dash in address to match domain below > Online photo gallery at www.wading-in.net >>>...over limited distances... >>> [quoted text clipped - 21 lines] > But the photons are still travelling _tangentially_ at the speed of > light No, only the angular rate of the beam. The photons are only travelling in the direction they were sent: outward (at c) "radially" The "beam" is really just how we say a contiuous stream of light, but it is nothing but "particles" (photons) going in one direction. Think of it as a stream of water and you turn very quickly. The water speed never changes but a child running could not keep up with the tangential speed (far enough out). Double the distance, double the tangential rate (but the water is still travelling outward at a constant speed (ignoring frictional losses). > so doesn't that make their particles faster than the speed of > light? Nope. Just the _beam_ rate at some point far enough off... not the speed of the particles. Cheers, Alan Signature-- r.p.e.35mm user resource: http://www.aliasimages.com/rpe35mmur.htm -- r.p.d.slr-systems: http://www.aliasimages.com/rpdslrsysur.htm -- [SI] gallery & rulz: http://www.pbase.com/shootin -- e-meil: Remove FreeLunch. > >>>...over limited distances... > >>> [quoted text clipped - 23 lines] > > No, only the angular rate of the beam. Huh? Didn't you just say... "The angular rate of the beam is > >>constant but at a point far enough along the beam the tangential > >>velocity of the beam can be many-many times the speed of light" You just said above that the tangential velocity of the beam can be many-many times the speed of light, so something (tangential photons) is/are going on faster than light here. The photons are only travelling > in the direction they were sent: outward (at c) "radially" > > The "beam" is really just how we say a contiuous stream of light, but it > is nothing but "particles" (photons) going in one direction. I know/understand that. The beam of light/packets of photons are traveling at a speed of c (speed of light) outwards, but this still doesn't explain how the tangential parts of that beam (still packets of photons) are able to travel many times faster than the speed of light. Look, either something (ie. some part of the beam/the tangential packets of photons in that beam) is travelling faster than the speed of light or it isn't... Which is it > Think of it as a stream of water and you turn very quickly. The water > speed never changes but a child running could not keep up with the > tangential speed (far enough out). Double the distance, double the > tangential rate (but the water is still travelling outward at a constant > speed (ignoring frictional losses). Good explanation, I now at least understand part of your explanation, but here is where I take exception.. Imagine, just imagine if you were able to rotate that sprinkler fast enough so that the tangential/outer packets of/stream of water were able to travel twice the speed of light (disregarding friction in air and the fact that the metal of the sprinkler might melt because of friction and/or break apart under the stress of such super speed) - wouldn't the water stream be traveling angularly outward at the same rate as before, but, and here's the big caveat, wouldn't the tangential packets of water _within_ the angular projection of water be traveling/spinning around the angular/radial axis at 2c within that 1c angular stream? Another way to look at it... Imagine a car loses control and skids off an embankment at 50mph, it s speed is 50mph in angular velocity, _however_ as it is flying through the air it is rolling (imagine a spit over a Bar-B-Q) at twice the speed of light (again minus friction in air/other physical limitations normally experienced). You get my point? In both examples, whether careening car or photons the angular speed is at (or in the car's case), or below the speed of light, so no "speed limit" is violated whether state law (assuming the speed limit is either 55mph or 65mph) or Einsteinian "law". However, the tangential velocity (in the car's case, the speed at which it rolls) _does_ violate the speed of light. So I'm still asking, even in special situations like tangential movement of a packet of photons or a car rolling, _how is this possible_? Is the speed of light limit only applicable to angular velocity and not other forms of velocity (ie. tangential velocity)? Both are just "speed"/movement/velocity, so what goes for one direction (angular movement) should logically apply to speed/movement (tangential movement) in another direction as well. ...Unless the speed of light is more a "suggestion" than a "law". Then al sorts of weird thing happens past the speed of light and effects precede causality and (backwards) time travel (at least) becomes more than a wish but an established fact. > > so doesn't that make their particles faster than the speed of > > light? [quoted text clipped - 4 lines] > Cheers, > Alan Again, forget about wavelengths/frequencies and think just packets of balls/photons, as mentioned in my first requoting of you... "The angular rate of the beam is > >>constant but at a point far enough along the beam the tangential > >>velocity of the beam can be many-many times the speed of light" so aren't the tangential particles/packets of photons/balls _within_ the beam of light still traveling at more than the speed of light _tangentially_ even though the light beam itself is traveling ahead angularly at the speed of light? I appreciate your time/explanations, Alan, I'm just trying to get closer to the truth, whatever that may be... > The photons are only travelling > > in the direction they were sent: outward (at c) "radially" [quoted text clipped - 9 lines] > packets of photons in that beam) is travelling faster than the speed of > light or it isn't... Which is it Imagine you have a flash gun set up 12 metres behind a translucent screen. It's a high-speed flash gun and goes to full power instantly. You're observing it from a long way away the other side of the screen (so the time taken for light to reach you from any part of the screen will be constant and can be ignored). .-Y------------------ 15m.-' | .-' |9m You, a long way away--> .-' | Flash F-----12m----X------------------ '-. | '-. | FX = 12m, FY = 15m, XY = 9m 15m'-. | '-| (Diagram will only work if viewed in a fixed-width font.) 40ns after the flash fires the front edge of the pulse of light has traveled 12m and reaches X. From your point of view (and ignoring the time taken for the light to travel from the screen to you) you will see a bright point of light at X. The rest of the screen will be dark because no light has reached those parts of the screen yet. 50ns after the flash fires the pulse has traveled 15m and reaches Y. From your point of view you now see a circle of light of radius 9m centred on X. But Y is 9m away from X, so from your point of view that expanding ring of light has moved from X to Y at an average speed of 9m/10ns = 9x10^8 m/s, or 3 times the speed of light. Note, however, that although you see the edge of the circle moving outwards at several times the speed of light, no component of the system is moving any faster than c. The point of first contact between the light and the screen is moving across the screen from X to Y at an average speed of 3c, but there's nothing physical moving across the screen from X to Y at all. The photons themselves are moving from F towards X or Y (and thence towards you) at c. It's a similar situation with the flashlight beam. There is no "beam" as such. If you sweep the flashlight beam across the same screen from a sufficient distance the point at which the spot of light moves across the screen can travel as fast as you like, but the individual photons are still moving at no faster than c. SignatureMatthew Winn [If replying by mail remove the "r" from "urk"] But their is a tantalizing quirk that says 'maybe it can be done' and people go nuts trying to exploit it. Back to the bus analogy: A bus goes at velocity V and the people on the bus do 'the wave' at velocity W and so the wave of standing people is traveling at W+V though no 'thing' is traveling faster than V. If, when the bus passes you throw a package to the last person on the bus and the person passes the package forward then the package is indeed traveling faster than the bus at velocity W+V. This won't work with a physical bus at light speed because the bus becomes - as we sense it - a 2d pancake when traveling at light speed, which it can't anyway, and so hitting the last person on the bus is impossible. Light, as far as is known, travels in uncompressed wave packets with a beginning and an end and a group of photons travel in a larger wave also having a beginning and end. But so far, and probably till the end of time, no one has managed to send information that travels forward in a wave packet of light and then sense it at the other end. Definitely a late at night with a pitcher of beer topic. All the above fast-and-loose with details etc., it won't get you a pass on the Physics IV final. SignatureNicholas O. Lindan, Cleveland, Ohio Darkroom Automation: F-Stop Timers, Enlarging Meters http://www.nolindan.com/da/index.htm n o lindan at ix dot netcom dot com > But their is a tantalizing quirk that says 'maybe it > can be done' and people go nuts trying to exploit [quoted text clipped - 14 lines] > at light speed, which it can't anyway, and so hitting the > last person on the bus is impossible. Find a way for the bus's (and its occupants') mass to be reduced to zero and would you still get this "pancake compression" effect? > Light, as far as is known, travels in uncompressed wave > packets with a beginning and an end and a group of photons [quoted text clipped - 14 lines] > http://www.nolindan.com/da/index.htm > n o lindan at ix dot netcom dot com All this "tangentially" ;-) sounds very similar to Einstein's postulation/imagination of what would it look like if a person/hitchiker were riding on the end of a light beam with a ?flashlight, would all be darkness or would the light from the flash light be traveling at twice the speed of light but only at the speed of light from the hitchhiker already goign at the speed of light (by riding at the end of the light beam)... 186,000 MPS, it's just not a good idea, it's the LAW. SignatureThere are those who believe that life here, began out there, far across the universe, with tribes of humans, who may have been the forefathers of the Egyptians, or the Toltechs, or the Mayans. Some believe that they may yet be brothers of man, who even now fight to survive, somewhere beyond the heavens. The Lone Sidewalk Astronomer of Rosamond Telescope Buyers FAQ http://home.inreach.com/starlord Sidewalk Astronomy www.sidewalkastronomy.info The Church of Eternity http://home.inreach.com/starlord/church/Eternity.html Why not post this line of posts to S.A.A. and see what you get back? SignatureThere are those who believe that life here, began out there, far across the universe, with tribes of humans, who may have been the forefathers of the Egyptians, or the Toltechs, or the Mayans. Some believe that they may yet be brothers of man, who even now fight to survive, somewhere beyond the heavens. The Lone Sidewalk Astronomer of Rosamond Telescope Buyers FAQ http://home.inreach.com/starlord Sidewalk Astronomy www.sidewalkastronomy.info The Church of Eternity http://home.inreach.com/starlord/church/Eternity.html > Why not post this line of posts to S.A.A. and see what you get back? A stream of replies that will make UC sound like Dale Carnegie. Though one can hope Archemides Plutonium might contribute ... oh, wait, I shouldn't have said that ... SignatureNicholas O. Lindan, Cleveland, Ohio Darkroom Automation: F-Stop Timers, Enlarging Meters http://www.nolindan.com/da/index.htm n o lindan at ix dot netcom dot com > > Why not post this line of posts to S.A.A. and see what you get back? > [quoted text clipped - 8 lines] > http://www.nolindan.com/da/index.htm > n o lindan at ix dot netcom dot com Groucho Marx says... "That's the most ridiculous thing I evah hoid"... "I once shot an elephant in my photons, how he got into my photons I'll never know..." Curly says... "E=mc nyuck nyuck" (angular velocity of light through a watermelon only) Einstein says... "Imagination is more important than... Moe, Larry the cheese! Moe, Larry the cheese! Nyip nyip nyip nyip nyip! Boink!!! Ouch!!!" Moe says... "Why I awdda...." > But their is a tantalizing quirk that says 'maybe it > can be done' and people go nuts trying to exploit [quoted text clipped - 22 lines] > managed to send information that travels forward in a > wave packet of light and then sense it at the other end. The point being that the "beam" rotating just causes photons to fly in a direction. That gives a constant c for the photons. But the position along the beam can move at any speed. It is massless, energyless, informationless. Signature-- r.p.e.35mm user resource: http://www.aliasimages.com/rpe35mmur.htm -- r.p.d.slr-systems: http://www.aliasimages.com/rpdslrsysur.htm -- [SI] gallery & rulz: http://www.pbase.com/shootin -- e-meil: Remove FreeLunch. > > The photons are only travelling > > > in the direction they were sent: outward (at c) "radially" [quoted text clipped - 58 lines] > Matthew Winn > [If replying by mail remove the "r" from "urk"] Thanks for the diagram/explanation, Mathew, but it still doesn't explain how light can actually travel (not appear to travel from a particular perspective) 300 times the speed of light! To requote a previous quote and link... " I was wondering if the article was speaking of this, or a variation > of it: http://www.straightdope.com/mailbag/mphasevel.html Well, now I _finally_ understand how a packet of particles (say that 10 times faster than the speed of light ;-)) can _appear_ to travel faster than light. Thanks for the link. But what I don't understand is... "In a forthcoming article in the journal Nature, Dr. Lijun Wang and colleagues of NEC at Princeton will detail an experiment in which they accelerated light pulses to AT LEAST THREE HUNDRED TIMES c! Furthermore, Italian scientists at the National Research Council say they have pushed microwaves to 1.25c!" Not everything is perspective tricks and/or semantics in light speed measurement, so what I want to know is how/under what special circumstances can light _in reality_ travel many humdred times faster than the speed of c regardless of medium or perspective or mathematics, _real_ _measurable_ _supraluminal_ _speed_. Thanks for the explanations, keep 'em coming :-) >> The photons are only travelling >>> in the direction they were sent: outward (at c) "radially" [quoted text clipped - 54 lines] > across the screen can travel as fast as you like, but the individual > photons are still moving at no faster than c. You know, what we should do is combine this thread with the one containing Kodak's financial statements. > >> The photons are only travelling > >>> in the direction they were sent: outward (at c) "radially" [quoted text clipped - 57 lines] > You know, what we should do is combine this thread with the one > containing Kodak's financial statements. Why, are Kodak's prfits disappearing faster than light speed? >> The photons are only travelling >> [quoted text clipped - 55 lines] > across the screen can travel as fast as you like, but the individual > photons are still moving at no faster than c. Excellent. Exactly right. Thanks Matthew. Cheers, Alan Signature-- r.p.e.35mm user resource: http://www.aliasimages.com/rpe35mmur.htm -- r.p.d.slr-systems: http://www.aliasimages.com/rpdslrsysur.htm -- [SI] gallery & rulz: http://www.pbase.com/shootin -- e-meil: Remove FreeLunch. >>>>>...over limited distances... >>>>> [quoted text clipped - 34 lines] > many-many times the speed of light, so something (tangential photons) > is/are going on faster than light here. > The photons are only travelling > [quoted text clipped - 28 lines] > projection of water be traveling/spinning around the angular/radial > axis at 2c within that 1c angular stream? No. The photons (water packets) are going away from the source (radially). The spinning of the beam really only happens at the source (the sprinkler). The photons can only go outward. The "beam" appears to be turning (and far enough out it can be much faster than the speed of light), but the photons at the point where the beam is turning at 2c (tangentially) are only going at 1c (radially). To make it short: no mass (energy) is going faster than light. But beyond a certain point the tangential velocity of the beam (which is a position, not mass or energy) that is moving. > Another way to look at it... > [quoted text clipped - 22 lines] > precede causality and (backwards) time travel (at least) becomes more > than a wish but an established fact. You just don't get it. Photons (things) can only go in that one direction (radial). The tangential "velocity" is just the speed of a point in space. That point is a position. Not a "thing". That position along the beam is massless and energyless and therefore has no speed limit.... A "beam of light" is not a single thing. It is a bunch of little things that are all going in the same direction. If I turn it at some number of degrees per second (angular rate) the photons go away at c. But at some point along the beam, the angular rate of the beam is c and 2x farther our it is 2x and so on. But NO MASS OR ENERGY IS GOING FASTER THAN C. Just the imaginary position of the beam. In numbers: I have a beam shooting out photons. The photons go out at c. I turn the beam (like a lighthouse) at 30° per second. At 352,251,076 meters away along the beam, the photons there are still travelling away at c (2.99X10^8 m/s). The beam at that point is sweeping at a right angle to the direction of movement of the photons there. That point on the beam is "changing positions" at c and at a right angle to the photon that is still going outward at c. Nothing of mass/energy is travelling at a right angle to the beam, only that point along the beam is moving. Now, if I go 2X as far along the beam (704,502,152 m). The photons there are still travelling at c and still outward. The point along the beam is now moving at 2X C at a right angle to the photon stream at that point. But that point is just a position. It is neither energy nor mass. It is just an idea. > so aren't the tangential particles/packets of photons/balls _within_ > the beam of light still traveling at more than the speed of light > _tangentially_ even though the light beam itself is traveling ahead > angularly at the speed of light? No. The "mass" (photons) are going one way. The "point along the beam" is travelling faster than c. But it is massless, energyless and therefore can do as it wants. It's not a thing. Cheers, Alan Signature-- r.p.e.35mm user resource: http://www.aliasimages.com/rpe35mmur.htm -- r.p.d.slr-systems: http://www.aliasimages.com/rpdslrsysur.htm -- [SI] gallery & rulz: http://www.pbase.com/shootin -- e-meil: Remove FreeLunch. > >>>>>...over limited distances... > >>>>> [quoted text clipped - 163 lines] > -- [SI] gallery & rulz: http://www.pbase.com/shootin > -- e-meil: Remove FreeLunch. I think I might have gotten it, Alan. Thanks for the explanation. But my question remains is the "thing" being measured as going more than c tangentially really a coordinate that the photons pass by at c or something else? Why the claims of 300x c tangentialy if all it is is an exercise in physics semantics and the wave packets of photons are still just travelling in reality at c. Can anything travel _in reality_ (not in mere apparent coordinate measurements but in actual reality) faster than c and under what special circumstances? I have heard that light/photons actually do have mass but its extrememly extremely tiny amount of mass -- if there was some way of reducing a particle's mass to less than that of a photon would that increase the possible real speed of that particle beyond c? Would passing a beam of particles through some kind of anti-gravity field (I know this is getting into the realm of science fiction, now) decrease their mass enough to allow for higher than c speeds? I will be away from my computer during the holidays but will read any answers posted and get back to answering (or posing questions as the case may be ;-)) when I return. By the way, Happy Thanksgiving to you Alan and anybody else who is reading this > I think I might have gotten it, Alan. Thanks for the explanation. But > my question remains is the "thing" being measured as going more than c [quoted text clipped - 6 lines] > light/photons actually do have mass but its extrememly extremely tiny > amount of mass -- if there was some way of reducing a particle's mass This is literally where the E=mc^2 comes into play. Photons are indeed massless, but they do have energy (in proportion to their frequency) and it is "energy" (whether in the form of mass or energy) that is affected by gravity. The nitty-gritty expl.: http://www.math.ucr.edu/home/baez/physics/ParticleAndNuclear/photon_mass.html or http://en.wikipedia.org/wiki/Photons#Physical_properties > to less than that of a photon would that increase the possible real > speed of that particle beyond c? Would passing a beam of particles > through some kind of anti-gravity field (I know this is getting into > the realm of science fiction, now) decrease their mass enough to allow > for higher than c speeds? Since nobody know what the physical laws of an anti-gravity field might be, it's hard to say. It is postulated that gravity is the exchange of gravitons (messenger particles) between all bits of mass in the universe. Since gravity is a force that exists between all things in the universe (1/r^2) that makes for a lot of gravitons flying hither and yonder. Nobody has detected a graviton or a bunch of gravitons. So, "anti-gravity" would need -ve gravitons (or anti-gravitons) of some kind. As for your last sentence, as anything is pushed to the speed of light, the energy required to do so is infinite. This can really drive up your electric bill if you're not careful. Since photons are massless to begin with, their mass can't be decreased much further. But even if you exchange all of something's mass for photons, and if that energy were photons, then the max speed would be c. There is a case where particles exceed the speed of light in a liquid. Where the speed of light in water is 0.75 of c, then particles that travel faster than that speed (but less than c) cause Cherenkov radiation (the erie blue light in a cooling tank or reactor). http://en.wikipedia.org/wiki/Image:TrigaReactorCore.jpeg > I will be away from my computer during the holidays but will read any > answers posted and get back to answering (or posing questions as the > case may be ;-)) when I return. Enjoy your Turkey weekend. > By the way, Happy Thanksgiving to you Alan and anybody else who is > reading this And to you (CDN TG was in Oct.) and all the yanks. Cheers, Alan Signature-- r.p.e.35mm user resource: http://www.aliasimages.com/rpe35mmur.htm -- r.p.d.slr-systems: http://www.aliasimages.com/rpdslrsysur.htm -- [SI] gallery & rulz: http://www.pbase.com/shootin -- e-meil: Remove FreeLunch. > ...over limited distances... > [quoted text clipped - 15 lines] > And, most importantly, does this mean I'll get back my 35mm SLR photos > from the processor before I take them? ;-) You need to go back and re-read it. The "mode" is light traveling through a vacuum. And you've got the quotation all garbled. It only worked over a distance of about 1 meter and DID NOT carry any signal. > > ...over limited distances... > > [quoted text clipped - 17 lines] > > You need to go back and re-read it. I just did. You need to go back and re-read it yourself. The "mode" is light traveling > through a vacuum. That only refers to a quote nearer the top of the page which is: ""It's very counterintuitive, but under certain circumstances you can have light travel in a vacuum in a mode which is faster than light," said Raymond Chiao, a physics professor at the University of California at Berkeley." And you've got the quotation all garbled. The quotation is fine, and was copied and pasted v-e-r-b-a-t-i-m, what _is_ garbled is your understanding of the quote, possibly in reference to modes as the top of the article mentions a vacuum mode and the bottom of the article mentions the mode as a mathematical entity: "The beams contain a mathematical entity, called modes -- the patterns by which the waves hang together -- that outpace light. But there is no physical entity that does so." Both talk about modes but one refers to the medium of empty space and the other refers to modes as "patterns by which the waves hang together". Understand? > It only worked over a distance of about 1 meter I know, hence my original posts' saying, if I may quote myself: "...over limited distances..." and DID NOT carry any > signal. Actually, all we know is that the scientist who conducted that mirror experiment to test for faster than light travel didn't _claim_ it carried a signal, that's not to say it couldn't, wouldn't, didn't - only that they did_n't_ make the claim that it did. So, after very clearly explaining this, again, I will re-iterate the question, in the hopes that now everything I quoted and said/asked is clear... "What the heck is a mode (a la mode?) and if its just a mathematical > > entity how can it travel faster than light if it has no physical > > existence - how can the patterns of the light outpace the light itself > > and how/why are the two separate things? Is this "modality" some weird > > kind of perception changes existence quantum phenomenon?" Please note that the "modality" I refer to in my questions above is not "mode" as in the medium light travels through, ie. a vacuum, but the mathematical entity of the way patterns of lights hang together. How can the patterns of light outpace the light beam/photons themselves, and whether on not they can or can't carry a signal, how can these patterns have no existence? If they have no existence than they (the patterns themselves) can have no measurable speed/velocity and hence can't be measured traveling faster than light or green jello for that matter! ;-) |
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