Known physics defeated by simple puzzle?
in [Relativity]
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From: Inertial on 7 Apr 2010 22:22 "Ste" <ste_rose0(a)hotmail.com> wrote in message news:45bff01f-f153-402b-a75b-fa56ccb7a069(a)y17g2000yqd.googlegroups.com... > On 7 Apr, 23:08, PD <thedraperfam...(a)gmail.com> wrote: >> On Apr 7, 4:57 pm, Ste <ste_ro...(a)hotmail.com> wrote: >> >> >> >> >> >> > On 7 Apr, 16:57, PD <thedraperfam...(a)gmail.com> wrote: >> >> > > On Apr 6, 7:12 pm, Ste <ste_ro...(a)hotmail.com> wrote: >> >> > > > We've had this one before Paul. No experiment of this kind (i.e. >> > > > trying to confine objects moving at relativistic speeds) has ever >> > > > been >> > > > performed. I even gave sources last time for this statement. >> >> > > That is simply not true. At RHIC, for example, where nucleus-nucleus >> > > collisions are done, the density of the quarks and gluons goes up >> > > precisely because of this Lorentz contraction. The nucleus is >> > > "squashed" and the density goes up. This is essential to both the >> > > design and the operation of this multimillion dollar facility. >> >> > > Furthermore, secondary particle emission from particle collisions >> > > have >> > > been done in both fixed target and collider facilities. Under both >> > > circumstances, relativity predicts the uniform distribution of those >> > > secondaries according to a variable called rapidity. In experiments, >> > > calorimeters are then arranged around the collision point and >> > > segmented in regular rapidity bins. Naturally, because the two >> > > experiments are viewing the same collisions from two different >> > > reference frames, the length binning for equal rapidity bins is >> > > considerably different, precisely because of Lorentz contraction. >> > > Thus, the distribution by rapidity, as shown by the particle deposits >> > > in the calorimeter, is an indirect but definitive check on Lorentz >> > > contraction. Experimentally, the match-up is exquisite. >> >> > > It's unfortunate that your web references are not accurate on this >> > > score, and have led you to the impression that Lorentz contraction is >> > > all hypothetical and without experimental support. I will just >> > > attribute this to the lack of depth of experimental information >> > > you've >> > > been able to lay your hands on. >> >> > I really don't understand enough about how these machines work, and >> > almost certainly never will, so it's pointless me attempting to >> > reconcile what you say. All I will repeat is that a number of >> > scientific sources, including a number of published scientific papers, >> > have insisted that there has been no direct measurement of a physical >> > length contraction. >> >> "Direct" is perhaps the key word. It is unfortunate that those papers >> led you to the conclusion that it has not been experimentally verified >> at all. I take no responsibility for confusion on your part that stems >> from the limited selection of material you choose to read. > > Paul, I was quite clear, and was even clearer on previous occasions: > there is no direct evidence. Quite simply, there have been no > experiments where an object of a significant length has been > accelerated and then a physical confinement attempted, with the > outcome that if the object had not contracted, either the setup would > noticably explode or it would be simply impossible to "shut the doors > properly". > > I hadn't been led to believe anything except that the kind of > experiment I describe above (in other words, one corresponding to the > ladder and barn scenario) has not been performed. > > > >> > And indeed, whether there is experimental evidence >> > or not, I still have not heard any compelling *explanation* for how >> > two objects could each physically contract to a smaller size relative >> > to the other. >> >> The definition of length is completely reliant on establishing >> simultaneity. >> Since simultaneity is frame-dependent, it is no wonder that length is >> frame-dependent. > > Indeed. Except I've previously asked for simultaneity to be defined in > a frame-independent manner - It can't be. It is a frame dependent notion. Just like velocity cannot be expressed in a frame independent manner. Now .. you CAN express intervals between events in a frame independent way. But that is a combination of durations and distances. if you are talking about just distance (or length) or just time duration, then they are frame dependent. It is a bit like looking at a pair of objects, A and B. Consider the coordinates of B wrt a set of orthogonal axes centered around A. You will get different x, y and z coordinates depending on how you orient the axes. ie they are frame dependent. However, the sum of the squares of the x, y and z values will be the same, regardless of the choice of orientation of axes.
From: Peter Webb on 7 Apr 2010 22:40 "Ste" <ste_rose0(a)hotmail.com> wrote in message news:45bff01f-f153-402b-a75b-fa56ccb7a069(a)y17g2000yqd.googlegroups.com... On 7 Apr, 23:08, PD <thedraperfam...(a)gmail.com> wrote: > On Apr 7, 4:57 pm, Ste <ste_ro...(a)hotmail.com> wrote: > > > > > > > On 7 Apr, 16:57, PD <thedraperfam...(a)gmail.com> wrote: > > > > On Apr 6, 7:12 pm, Ste <ste_ro...(a)hotmail.com> wrote: > > > > > We've had this one before Paul. No experiment of this kind (i.e. > > > > trying to confine objects moving at relativistic speeds) has ever > > > > been > > > > performed. I even gave sources last time for this statement. > > > > That is simply not true. At RHIC, for example, where nucleus-nucleus > > > collisions are done, the density of the quarks and gluons goes up > > > precisely because of this Lorentz contraction. The nucleus is > > > "squashed" and the density goes up. This is essential to both the > > > design and the operation of this multimillion dollar facility. > > > > Furthermore, secondary particle emission from particle collisions have > > > been done in both fixed target and collider facilities. Under both > > > circumstances, relativity predicts the uniform distribution of those > > > secondaries according to a variable called rapidity. In experiments, > > > calorimeters are then arranged around the collision point and > > > segmented in regular rapidity bins. Naturally, because the two > > > experiments are viewing the same collisions from two different > > > reference frames, the length binning for equal rapidity bins is > > > considerably different, precisely because of Lorentz contraction. > > > Thus, the distribution by rapidity, as shown by the particle deposits > > > in the calorimeter, is an indirect but definitive check on Lorentz > > > contraction. Experimentally, the match-up is exquisite. > > > > It's unfortunate that your web references are not accurate on this > > > score, and have led you to the impression that Lorentz contraction is > > > all hypothetical and without experimental support. I will just > > > attribute this to the lack of depth of experimental information you've > > > been able to lay your hands on. > > > I really don't understand enough about how these machines work, and > > almost certainly never will, so it's pointless me attempting to > > reconcile what you say. All I will repeat is that a number of > > scientific sources, including a number of published scientific papers, > > have insisted that there has been no direct measurement of a physical > > length contraction. > > "Direct" is perhaps the key word. It is unfortunate that those papers > led you to the conclusion that it has not been experimentally verified > at all. I take no responsibility for confusion on your part that stems > from the limited selection of material you choose to read. Paul, I was quite clear, and was even clearer on previous occasions: there is no direct evidence. Quite simply, there have been no experiments where an object of a significant length has been accelerated and then a physical confinement attempted, with the outcome that if the object had not contracted, either the setup would noticably explode or it would be simply impossible to "shut the doors properly". I hadn't been led to believe anything except that the kind of experiment I describe above (in other words, one corresponding to the ladder and barn scenario) has not been performed. ______________________________ Funny, in this very thread - and as shown above - you were given exactly this type of experiment, whereby a particle moving close to the speed of light has its length (in the QM equations) reduced so that on the axis of its direction of travel it can fit inside a much smaller object - for example an atomic nucleus. Similarly, the accelerated particle sees the target as foreshortened, and hence denser, and if that were not the case then the interaction rate would differ from that experimentally observed. As is already clearly stated above. If you want to learn something, you should read the answers to the questions you ask.
From: Sue... on 7 Apr 2010 22:58 On Apr 7, 5:24 pm, Ste <ste_ro...(a)hotmail.com> wrote: > On 7 Apr, 15:49, "Inertial" <relativ...(a)rest.com> wrote: > > > > > "Ste" <ste_ro...(a)hotmail.com> wrote in message > > >news:cf5cd01b-0da3-41b0-88b5-69b2e678a011(a)z7g2000yqb.googlegroups.com... > > > > On 7 Apr, 05:08, "Inertial" <relativ...(a)rest.com> wrote: > > >> "Ste" <ste_ro...(a)hotmail.com> wrote in message > > > >> >> > Again, hidden in the meaning here is 100km/h > > >> >> > *relative to what*. An object cannot travel at *both* 100km/h *and* > > >> >> > 50 > > >> >> > km/hr *relative to me*. > > > >> >> I didn't say it could. But we are talking about things being real.. > > >> >> you > > >> >> claim that all observers have to agree about the value for it to be > > >> >> real. > > > >> > Yes, I do say that! > > > >> So velocity is not real, momentum is not real, kinetic energy is not > > >> real, > > >> length is not real, time is not real etc etc. > > > >> Is that REALLY what you want to be saying? > > > > But I'm not saying that, am I? > > > By implication, yes, you are > > > > You're the one putting these words in > > > my mouth. > > > No .. I am applying your definition. > > > If that is NOT what you want to be saying, then you should change yoru > > definition > > No Inertial, you're not applying my definition, because you don't even > understand my definition. We can't use your definition because Einstein's definition puts the ballistic light that W. deSitter never found on an imaginary axis. <<There is only one demand to be made of the definition of simultaneity, namely, that in every real case it must supply us with an empirical decision as to whether or not the conception that has to be defined is fulfilled. That my definition satisfies this demand is indisputable. That light requires the same time to traverse the path A > M as for the path B > M is in reality neither a supposition nor a hypothesis about the physical nature of light, but a stipulation which I can make of my own freewill in order to arrive at a definition of simultaneity.>> http://www.bartleby.com/173/8.html The ballistic light only *appears* for people of his time that applied Newtons mechanics to light particles. http://en.wikipedia.org/wiki/Emitter_theory In the formal statement the ballistic property vanishes. http://www.bartleby.com/173/17.html Sue...
From: Ste on 7 Apr 2010 23:00 On 7 Apr, 23:18, PD <thedraperfam...(a)gmail.com> wrote: > On Apr 7, 5:09 pm, Ste <ste_ro...(a)hotmail.com> wrote: > > > > > > > On 7 Apr, 16:59, PD <thedraperfam...(a)gmail.com> wrote: > > > > On Apr 6, 7:27 pm, Ste <ste_ro...(a)hotmail.com> wrote: > > > > > On 6 Apr, 19:44, PD <thedraperfam...(a)gmail.com> wrote: > > > > > > On Apr 5, 10:03 pm, Ste <ste_ro...(a)hotmail.com> wrote: > > > > > > > > You still haven't answered why 'fitting' must be absolute > > > > > > > Because of the obviousness of the concept. A thing cannot fit and at > > > > > > the same time not fit, because there is a logical contradiction in the > > > > > > meaning of those words. And nor can the state be subjective for each > > > > > > observer, otherwise that isn't materialism (and it isn't causal > > > > > > either). Or to repeat my earlier analogy, you can't hit a person over > > > > > > the head with a hammer, and merely daze him *at the same time as* > > > > > > cracking his skull wide open. > > > > > > This business about a thing fitting and not fitting being a > > > > > contradiction... > > > > > > A penny on the armrest of a plane is at rest in one reference frame > > > > > and not at rest in another reference frame. Is it not obvious to you > > > > > that there is a logical contradiction in those claims? > > > > > No, because *everyone* agrees about how the penny is moving with > > > > respect to any other object. > > > > But motion is not defined with respect to another object. It is > > > defined with respect to a coordinate system, a reference frame. > > > Then perhaps therein lies the problem. Ultimately, all "reference > > frames" ultimately anchor to real objects, > > This is not true. I think it is insofar as we're describing physical reality, and not just talking about geometry on paper. > > but "reference frames" are > > not a physical entities in themselves. As I've said, I have a > > practical turn of mind, so I'm always careful to understand how > > abstract concepts relate to something real. > > This should not lead you to therefore insist that reference frames by > definition anchor to real objects, whether you want that to be the > case for practical sensibilities or not. I'm *all* about practical sensibilities. > > > > > How does the > > > > > penny change from being at rest in one frame to not being at rest in > > > > > another frame, without there being some physical interaction with the > > > > > penny to cause that change? > > > > > Because it *doesn't* change from being "at rest" to "not at rest". > > > > There is no "change" at all. Both the man on the plane, and the man on > > > > the ground, agree that the penny is stationary relative to the flyer, > > > > and moving relative to the man on the ground. The penny does not > > > > "change" from being stationary to moving. What changes is the object > > > > to which you are making reference. > > > > I'm not making reference to any object. The motion of an object is > > > with regard to a coordinate system, a reference frame. This is basic, > > > high school physics. > > > As above. A "reference frame" is still a reference object > > (linguistically). > > No, it is not. A reference frame -- again a physics jargon term -- has > a very clear meaning tha you can look up to correct or augment your > pedestrian understanding of that word in everyday speech.http://en.wikipedia.org/wiki/Frame_of_referencehttp://www.answers.com/topic/frame-of-reference That page seemed to be consistent with my understanding. In any event, I don't think there's anything worth arguing over here - for all practical purposes, I understand what a frame is. > > And what we really mean by "reference frame" is that > > certain real objects have defined mathematical values for their > > properties (like defining certain objects to be at rest, and facing a > > certain direction), and the values of all other objects are calculated > > in relation to that. > > > But certainly, there is no need to make reference to a "frame" in > > order to calculate a "relative speed" between two objects. > > Yes, there is. Is there? (And I'm assuming we're disregarding SR). > And it turns out that the relative speed between two > objects as *measured* in different reference frames, is frame- > dependent. Observationally. Whether you think this is nonsense or not. And of course, I do think that.
From: Inertial on 7 Apr 2010 23:02
"Sue..." <suzysewnshow(a)yahoo.com.au> wrote in message news:b24bf0e3-7cdf-4390-a301-ff19dae3ae30(a)w17g2000yqj.googlegroups.com... > On Apr 7, 10:12 pm, "Inertial" <relativ...(a)rest.com> wrote: >> "Sue..." <suzysewns...(a)yahoo.com.au> wrote in message >> >> news:56c9fe57-49e7-4699-8542-43f273818b82(a)u31g2000yqb.googlegroups.com... >> >> >> >> > On Apr 7, 9:39 pm, PD <thedraperfam...(a)gmail.com> wrote: >> >> On Apr 7, 8:21 pm, Ste <ste_ro...(a)hotmail.com> wrote: >> >> >> > On 7 Apr, 22:45, PD <thedraperfam...(a)gmail.com> wrote: >> >> >> > > On Apr 7, 4:24 pm, Ste <ste_ro...(a)hotmail.com> wrote: >> >> >> > > > But you still don't get it. "Fitting" is not a relationship >> >> > > > between >> >> > > > obsever and ladder. It is a relationship between ladder and >> >> > > > barn. >> >> > > > Why >> >> > > > on Earth would the observer's presence and circumstances affect >> >> > > > the >> >> > > > fitting of these two objects, that are totally independent of >> >> > > > the >> >> > > > observer? >> >> >> > > To help you understand this, I'd like for you to give me a very >> >> > > precise definition of what you mean when you say that one object A >> >> > > will "fit" inside object B, when A and B are relatively moving. >> >> > > Depending on the quality of your definition, I may probe it with >> >> > > some >> >> > > additional questions and scenarios to see if it works. >> >> >> > It's relatively straightforward. "Fitting" is when the ladder is of >> >> > such length that it would be possible to close both doors on the >> >> > barn, >> >> > and for the ladder to be contained completely inside. >> >> >> Remember the ladder is moving relative to the barn. >> >> How does one determine that the ladder is contained completely inside, >> >> exactly? >> >> For example, I could shut one door and open it, while the front of the >> >> ladder is inside the barn, and then I could walk around to the back of >> >> the barn and shut the other door, while the back of the ladder is >> >> inside the barn. But by that time, the front of the ladder may have >> >> struck the first door. Is it still true that the ladder fits inside >> >> the barn? >> >> >> > > > > > but that's not materialism - it's going >> >> > > > > > back to saying that the tree falling in the forest only >> >> > > > > > makes a >> >> > > > > > sound >> >> > > > > > if an observer heard it. >> >> >> > > > > Nonsense. You are the one who above pointed out the with the >> >> > > > > object moving >> >> > > > > at 50km/hr and 100km/hr you have to consider the objects you >> >> > > > > are >> >> > > > > measureing >> >> > > > > relative to (ie the frame of reference). >> >> >> > > > Yes. But you only have to reference two objects to describe a >> >> > > > closing >> >> > > > speed. You don't say "objects A and B were closing at 100kmh >> >> > > > according >> >> > > > to Jack" and "objects A and B were closing at 50kmh according to >> >> > > > Jill", because that would be contradictory (assuming that the >> >> > > > definition of "kmh" is itself common between Jack and Jill). >> >> >> > > > You could say "objects A and B were closing at 100kmh according >> >> > > > to >> >> > > > Jack" and "objects A and B were closing at 100kmh according to >> >> > > > Jill", >> >> > > > but since the observer has no bearing on the measurement, why >> >> > > > reference him at all? >> >> >> > > But it does. Closing velocity is also frame dependent. >> >> > > Suppose you have objects A and B, and you have observers Jack (at >> >> > > rest >> >> > > relative to A), Larry (at rest relative to B), Mary (moving >> >> > > relative >> >> > > to both A and B such that A and B have equal speeds relative to >> >> > > Mary), >> >> > > and Nancy (moving relative to A, B, and Mary). >> >> >> > I must admit I've no clear picture at all about this scenario. >> >> >> > > Then what will be true >> >> > > is that the closing speeds between A and B will have the same >> >> > > answers >> >> > > for Jack and Larry, but that number will be different than the >> >> > > closing >> >> > > speed between A and B according to Mary, and all of those >> >> > > different >> >> > > than the one according to Nancy. >> >> >> > No, I reject this. The closing speed between A and B is universal, >> >> > no >> >> > matter how the observers move around relative to A and/or B. >> >> > According to SR not LET: >> >> No .. according to neither. Unless you are talking about the underlying >> Galilean/Newtonian 'reality' of LET that we cannot measure. >> >> > Can the fast magician drop the small horizontal >> > hula hoop over the long levitated lady as she zips >> > across the stage at near light speed? He is an amateur >> > magician who has yet to learn how to reattach >> > heads and feet so don't be wrong. >> >> :) > > The magician's assistant thanks you for her > life and as a token of gratitude has asked that > your name be removed from the list of LET advocates. That's fine with me .. I should never have been on the list in the first place. maybe someone put me on the subscription list as a xmas present? At least its not as bad as reader's digest .. you don't get those annoying prize offers from the LET list. |