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Four Forces and Gravitons

  1. Feb 13, 2004 #1
    Four Forces and "Gravitons"

    Hello. Well, we were watching an old video, presumably from the 80s or so in physics class, and it stated:

    There are 4 basic forces in the universe: ElectroMagnetic, Gravity, Weak and Strong.

    Now, EM and Gravity make sense to me that they exist, but weak and strong seem iffy. I'm not really even sure what they are. Later in the video, something else deeply disturbed me - they said gravity was caused by particles called gravitons. Of course, it's theoretical, but it jsut seems whack.

    First of all, it doesn't seem logical that something that directly affects particles would be caused by particles. I dunno, I guess that seems circular to me.

    Seeing as the video was pretty old, what are some more modern and accepted theories on all this?
  2. jcsd
  3. Feb 13, 2004 #2


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    Yes, it's perfectly reasonable that "EM and Gravity make sense to me that they exist, but weak and strong seem iffy". EM and gravity are "large scale" forces that everyone deals with everyday. The "weak" and "strong" forces (more correctly called "weak nuclear force" and "strong nuclear force") are only observed in the nucleus of atoms and between elementary particles. Very precise experiments are required to observe them.
  4. Feb 13, 2004 #3


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    Re: Four Forces and "Gravitons"

    Actually, if you think about it carefully, you'll notice that at the very least, the strong force HAS to make sense. Consider the nucleus of an atom. It has in it only protons and neutrons (for heavier elements at least). While the neutrons are neutral electrically, the protons are not. Coulombic forces means that these protons, having the same electrical charge, want to repel each other. In fact, they are they are confined to such tiny volume of the nucleus, the repulsive forces are unbelievably large. Yet, you will notice that you and I and a lot of materials in our everyday lives are rather stable - we don't spontaneously decay into other elements due to the nuclei that made up our bodies and objects flying part because of the repulsive forces.

    This can only mean that there has to be at least one other force that somehow bound the constituents of a nucleus together, and this is the strong force. It binds not only the protons, but also the neutrons. However, it has a very short range, which is why we don't observe its effect. But by simply knowing that without it, the nucleus would not be a stable entity, I would think this would qualify as another force that SHOULD "make sense", if you think about it some more.

  5. Feb 15, 2004 #4
    Thanks a bunch. The strong and weak forces make sense now that someone explained they were inside the nucleus of an atom - this video didn't even explain that.

    If gravity is dependent on mass and distance, would protons be massive enough and close enough for gravity to hold them together dispite their electromagnetic..whats the word, repellance? I'm not really an expert..Is the EM forces making them repel greater than gravity would have them attract?

    Also, do "gravitons" seem physically logical? I mean, is there somethign else that makes more sense? (I know everything is possible, but some things are more probable)
  6. Feb 15, 2004 #5
    Hey Decker, a great bunch of questions. I'm just a novice compaired to most of the guys here but I think I can help you out.

    The force of gravity is much much much MUCH smaller then the electromagnetic force. I don't have the exact figure but you can bet its in the millions to billions of times smaller then the electromagnetic. Think about this, the electro-replusion(Coulomb force) in just a half inch of steel is able overcome the effect of gravity of the whole planet(try standing on it, do you fall through to the middle of the planet?) If that doesn't make sense to you remember it is the repulsion of the electrically negative electrons that swarm around nuclei that keep atoms from "touching" each other. Your feet never actually "touch" the floor as the repulsion between atoms and your shoe atoms causes you to float, albeit at so small of a distance to our everyday senses they might as well be touching.

    As far as the graviton, your right to be skeptical as it has never been directely observed, however..

    All the other forces(EM, strong, weak) have something called a "carrier" particle, in other words, it is the particle that allows the force to act over a distance. The Electro-magnetic force carrier is the Photon, The weak force has Z and W bosons, the Strong Force has gluons, but what does gravity have? The mysterious particle is called a graviton. We haven't actually seen one yet but we see evidence of it everyday( ie the moon is quite a distance from earth yet it still is attracted to earth and vice versa)
    Last edited: Feb 17, 2004
  7. Feb 17, 2004 #6
    Gravity and other forces acts as the certain essence aspiring to change the size of the channel of interaction (a string) between objects. Decreasing or increasing of space between objects has show as their interaction.
    Gravity always appears as the essence reducing this size. Gravity is absolutely and acts simultaneously in each point of universe.
  8. Feb 17, 2004 #7
    Which means gravity follows the inverse square law, and is a attractive force? I struggle to find the significance.
    Last edited: Feb 17, 2004
  9. Feb 17, 2004 #8


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    Re: Four Forces and "Gravitons"

    It is a problem of names. It is more clear if you consider on one side the bosons, on other hand the fermions. Roughly, bosons are forces, and fermions particles.

    Regretly the equivalence energy-matter and the equivalence wave-corpuscle let us to call everything "particles". But they still are different things.
  10. Feb 18, 2004 #9
    I doubt I should post anything, but I just wanted to throw in that my professor said that there is a delay in gravity, like there's a delay in light...you know, it looks instant, but it's not...anyway, the delay in the gravity is the same as the delay of light...I know physicists used to be looking for a "gravity wave," doesn't it seem strange that there would be such a funny coincidence between light and gravity? Sorry this isn't more scholarly, just wanted to mention it because it seems so interesting, and because gravitons were mentioned...maybe gravity is like light, make up of particles and waves and so forth.
  11. Feb 19, 2004 #10
    Reduction of space between objects corresponds to an attraction force.
    All forces are subjected to 1/r^2. It is determined by 4-dimension geometry of space. A Gravity force is equal to
    G (4pi) M1*M2/(4pi)r^2 indeed.
    Here (4pi)r^2 is a square of sphere with radius r.
  12. Feb 19, 2004 #11
    I really can’t see how the gravitational force can be made up of gravitons unless general relativity is not the proper description for gravity. The other three forces mediate through bosons and these bosons are just actors on the stage of space-time. The general approach taken in quantum field theory is to quantanize the force fields and this gives us the little discrete packets of field radiation that we call bosons. General relativity on the other hand puts gravity on a completely different footing than the three other forces, the gravitational field isn’t an actor on the stage of space-time but it is space-time itself. Quantanizing the gravitational field i.e. describing the field in terms of gravitons, means quantanizing space-time, which to me seems ludicrous. So either Einstein or gravitons are wrong.
  13. Feb 19, 2004 #12


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    Yes, it does (to me too, anyway). But it also makes sense in its funny relativistic way. There must be one speed that remains invariant under a lorentz transformation. If gravity did not travel at the speed of light, then momentum would not be conserved.
  14. Feb 19, 2004 #13
    Or they're both right. Something like that always seems to happen in physics. I heard they might be able to make it make sense by quantizing spacetime itself.
  15. Feb 19, 2004 #14
    Re: Four Forces and "Gravitons"

    Well, you must know about photons. Ever wonder what makes two charged pith balls repel or attract one another? A photon carries "light", and we know that light is an electromagnetic wave. Basically, the photon is the mediating particle of the electromagnetic force itself. Now does it seem logical that something that directly affects particles can be caused by particles?

    I think everybody would be confused if gravity turned out to be completely and fundamentally different from the other forces. Physicists think that all the forces converge into one force at very high energies, so there should be commonality between them.
  16. Feb 20, 2004 #15
    everything you believe or think you know was learnt
    stop believing the lies and relise the simplicity of our cosmos
    energy is a spectrum sound , light and heat
    simply misunderstood, and seperated because of our feeble perception
    You believe light and heat are seperate of sound because of their electromagnetic nature but really they are electromagnetic because of sound
    Gravity is merely the sound energy release of the sun to planets , planets to moons , moons to tide enliken to light reflection in the form of one mother f@##ing low frequency note
    the rhythm of our solar system in musical notes played by the sun

    "When the solution is simple, God is answering." Eistein

    The area between sound and heat is your c square in this equation E=mc2

    Tell them Logan Muspratt sent you
    and I'll tell you God sent me
  17. Feb 20, 2004 #16
    Re: Re: Four Forces and "Gravitons"

    I have found the general origin of all fundamental forces. This is display of properties of a photon on a scale of light frequencies.
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