Posted on 11/15/2003 8:43:52 PM PST by Diddley
First a disclaimer. I can handle the men on platforms throwing a ball. The physics of nuclear forces is a topic with which I have a very dated, limited exposure.
The way I would answer your question is that "force" is simply the description we give to describe when things are interacting. If one particle moves toward another and the second particle changes its behavior, then we describe the second particle as having been "forced" to change its behavior. The laws of physics describe in detail how the behavior will change.
In common usage, the word "force" tends to imply that a person could sense pressure or pain or some other manifestation of one object interacting with another. Physiologically, these sensations are just our own bodies or senses being interacted with and changing their behavior due to some other object.
The detailed behavior of the universe, whether we like it or not and whether it appeals to our intuition, is that "forces" in the physical world require time to elapse before the cause can create the effect.
A flare on the surface of the sun cannot be sensed on earth until about eight minutes after the event happens on the sun. Any effect on the earth is due to "radiation", either electromagnetic or particles, reaching the earth. ( The particles taking much longer than the electromagnetic radiation.)
The electromagnetic radiation will arrive at the earth in the form of what we call "light". Experiments have shown that light is "quantized"; that is, any photon of a given frequency carries a specific amount of energy.
One of Einstein's contributions was the understanding of the photo-electric effect. Shining a light on a piece of metal reveals that the energy of each emiitted electron from the metal is a function of the frequency of the light and not the intensity of the light. The experiment is consistent with the understanding that the light consists of "photons" each of which is capable of causing the emission of a single electron. Thus, any force caused by the distant movement of electrically charged particles can be demonstrated to have effect through the actions of photons moving at the speed of light from the source of the energy to its recipient.
The nuclear force is theorized to operate similarly. Interaction between particles which exhibit the strong force do so by exchanging particles to convey energy and momentum.
The "graviton" is the presumed particle which plays the role of conveying energy and momentum from one mass interacting with some other mass through the gravitational force. The force of gravity is much, much weaker than the other forces and efforts to detect gravitons have not yet been successful (last I heard).
In summary, the answer to the question would be "yes", all forces involve the exchange of particles. At the finest level, everything which causes "free space" not to be empty seems to have a description which involves both wave and particle properties. The interactions between them are what constitute the activity in our universe.
So THAT'S why my lamps are marked 'Hi Med and Lo' ...
That was Laplace's idea about 200 years ago, but it has since been shown to be wrong.
For one thing, a deterministic universe is its own 'simplest computer'. In order to calculate the trajectories in the manner you suggest, it would take an amount of computing power that would grow exponentially in time. Any finite computer would be overwhelmed in a finite time.
For another thing, you can't number the photons. Fundamental charged particle interactions suffer what's called an "infrared divergence", which means that the number of photons radiated in the course of the interaction depends on then energy cutoff at which you stop counting. If you take the cutoff all the way down to zero, the number of real photons emitted goes to infinity. No matter where you place the cutoff, you'll be missing something, so your calculation will necessarily be imperfect.
[Geek alert: if you think that this infinite sum of photons will lead to infinite quantities, you're right...but that's only half of the story. The interaction also gets a contribution from the virtual photons, and this contribution to the calculation is also infinite. However, it has an opposite sign from the real contribution, and the two infinite sums almost exactly cancel. The remaining residue, as it turns out, is independent of where you place the cutoff. That said, the real contribution really is real, so you really can't count--or account for--all of the photons.]
Finally, and worst of all, many quantum events (such as subatomic decays) are uncaused, and cannot be accounted for by any mechanism involving particles in motion. If such an accounting were possible, then all ensembles of such events would necessarily obey an esoteric relation called Bell's Inequality. It is a fact of nature, however, that many real-world interactions violate Bell's Inequality. If you're interested, I wrote a brief sketch of Bell's Inequality (in the form of a Platonic dialogue) which may be found here.
Point of terminology: quarks aren't hadrons. Hadrons are particles composed of quarks.
For example, the pi+ decays first into a muon+ and a neutrino, then the muon decays into a positron (anti-electron) and an anti-neutrino?
A mu+ decays into a positron, an electron neutrino, and a muon anti-neutrino.
Hadrons decaying into leptons is thoroughly confusing to me, and implies that the former are composed of the latter somehow.
Well, no. Notice that in the pion decay you mentioned, an anti-muon and a muon neutrino were created. What happened was that when the pion decayed, the quark and antiquark--which were of different flavors, an up quark and an anti-down quark--annihilated into a virtual W+ boson. The W+ boson then "decayed" (manifested itself, really) in the form of a mu+ (i.e., an anti-muon) and a muon neutrino. One of these particles (the neutrino) carried one unit of "muon-ness", while the other (the mu+) carried negative one units of "muon-ness". The total muon-ness of the system was zero both before and after the pion decay.
It's the same deal with the decay of the mu+. The anti-muon-ness is conserved when it decays into the form of a muon anti-neutrino. It also emits a (virtual) W+ which instantly decays into a positron and an electron neutrino.
The conversion of a W+ into a positron and an electron neutrino (or a mu+ and a muon neutrino) is directly analogous to a high energy photon (i.e., a gamma ray) converting into an electron positron pair. The photon doesn't "contain" an electron and a positron prior to the conversion. Rather, at some point in time, the photon just connects to a single conserved electron current, doing a U-turn in time.
There are six quarks and six leptons. Of the gauge bosons, there is one photon, one Z, one graviton, a W+ and a W-, eight different gluons, and at least one Higgs (but there may be several). There is a Higgs-like particle in QCD called the pseudoscalar axion, but not everyone believes this will be manifest as a physical particle.
You might also count the anti-particles of the quarks and leptons, if you like, but the gauge bosons are their own anti-particles (save for the W+ and W-, which complement each other, and the eight gluons, ditto).
It is possible that neutrinos are also their own anti-particles. This was the formulation of Ettore Majorana, as opposed to the Dirac formulation which has both neutrinos and anti-neutrinos. If neutrinos were massless, as was thought until recently, then the two formulations would be mathematically equivalent. It turns out that neutrinos have nonzero masses, however, so someday we will know which formulation is correct.
So how many different fundamental particles are there? It depends how you count them. The string theorists will tell you there's just one.
It doesn't matter. The size of the calculation still grows exponentially with time. Pick a computer of any size you want. Eventually it will fall behind.
Your "[photon] counting stuff; is that a result of an observer changing what he is observing? If that's the case, then if one uses only mathematics and doesn't actally try to measure anything, then he wouldn't affect it, would he?
No, that's not what I'm talking about at all. I'm assuming Cartesian non-interfering omniscience (bunkum as that may be). My point is that there's no finite numbering scheme that you can use as the basis of grinding out your calculations. You ultimately have to pick some point at which you say, "I'm not including the rest of these photons in my calculations." And because you have to exclude some particles from your calculation, your answer can't really be exactly right.
And even if he did, WHICHEVER number that he chose would be the correct one, since my theory means that there is only ONE future path, and no matter what we do, we can only make the one decision: any idea of choice is an illusion.
How do you define "choice"?
It's probably even worse than you think.
Every particle in the universe exhibits both particle and wave behavior. The wave describing a particular particle is a function of space, describing the location of the particle, and time, describing the motion of the particle.
The value of the wave equation at any point in space relates to the probability of observing the particle at that position . Some positions will be more probable than others. But any position where the wave equation has a non-zero value represents a position where the particle might be found.
Einstein was very troubled by this aspect of quantum physics. He said "God does not play dice" with the universe. Einstein thought that it might be possible to know the value of some hidden variables that would then allow one to eliminate the uncertainty which is represented by the wave equations. Recent experiments support the idea that there are no hidden variables. The observed position of a particular particle is unknowable until after the observation is made.
This means that your computer program would be picking a value to use for the outcome of an interaction from all the possible values provided by the wave equation. There is no way that the computer is going to "pick" the same value that the actual universe "picks". This uncertainty would apply to every particle and every interaction.
And all I'm saying is that, even in a perfectly deterministic universe, such calculations are intractable in principle. (Moreover, not all perfectly deterministic systems are computable, but that's another can of worms.)
As to "choice"; let's say that I can go to work tomorrow or not go to work. I make a decison whether to go or not. What I'm saying is that the choice has ALREADY been made; it was made as soon as the universe began.
I don't see the philosophical difference, as long as I am my own simplest computer, because ultimately, nothing can predict me. Besides, if someone handed me a printout proving to me that all of my actions for the last three years were algorithmically predictable, it wouldn't change how I act or how I feel about myself.
Viewed a different way, if someone proved to me that many of my actions were instead decided by a truly random and unpredictable "Pop-a-Matic" in my brain, I wouldn't consider myself to be any more or less "in control" than if the "Pop-a-Matic" were exactly predictable. My decisions are, in large measure, a mystery to me in either case.
I may THINK that I have freewill,
That's as may be, but speaking for myself, I know I have freewill. That's because I define "freewill" as the process by which I make conscious decisions. Whether that's deterministic or random or something else, I can't tell you...but I suspect that it doesn't make any qualitative difference. You might be interested in my contributions to this thread.
If the guy is counting protons, whatever number he comes up with will be the number it is correct for the one path to continue.
You're still missing that point. Let me try one last time: whatever number he comes up with will be WRONG for the calculation to reflect the actual physics. Let "the path" go wherever it is destined; it will be as unpredictable as if it were random at some level. If a system's destiny is inscrutably hidden and unknowable in principle, can it really be called destiny?
:-)
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