Notices
Results 1 to 20 of 20
Like Tree7Likes
  • 1 Post By Physicist
  • 1 Post By Physicist
  • 1 Post By Jilan
  • 1 Post By Physicist
  • 1 Post By Jilan
  • 1 Post By Jilan
  • 1 Post By Physicist

Thread: The speed of the force of nature?

  1. #1 The speed of the force of nature? 
    Senior Member
    Join Date
    Jul 2014
    Posts
    115
    We know that electromagnetism and gravity move with the speed of light , so the strong nucleon force also move with the speed of light, right?
    Reply With Quote  
     

  2. #2  
    Senior Member
    Join Date
    Jun 2014
    Posts
    551
    Quote Originally Posted by johnzxcv View Post
    We know that electromagnetism and gravity move with the speed of light , so the strong nucleon force also move with the speed of light, right?
    No. The particle that mediates the electromagnetic force is the photon and that which mediates gravity is the graviton. Since each of these is an inverse square law these particles have zero mass. However the force that mediates the strong force is not an inverse square law. It drops off much faster (i.e. does not have the same functional form) than an inverse square law. The potential function for the strong force is the Yukawa potential. The particle which mediates this force therefore has mass and therefore the speed of the interaction should be less than the speed of light.
    Glitch likes this.
    Reply With Quote  
     

  3. #3  
    Senior Member
    Join Date
    Oct 2013
    Location
    UK
    Posts
    997
    They are known as pi mesons or pions for short.
    Pion - Wikipedia, the free encyclopedia
    Reply With Quote  
     

  4. #4  
    Senior Member
    Join Date
    Jun 2014
    Posts
    551
    Quote Originally Posted by Jilan View Post
    They are known as pi mesons or pions for short.
    Pion - Wikipedia, the free encyclopedia
    Thanks Jilan. I kept saying to myself Don't forget to tell them that this particle is a pion and yet I still forgot!
    Jilan likes this.
    Reply With Quote  
     

  5. #5  
    Banned
    Join Date
    Jul 2014
    Posts
    341
    In reply to Physicist, re: your pm to me.

    You're welcome! I don't know WTH is going on here...my "window of time" to reply is so short all I can anymore is "yes" "no" or "duh?" Every single time...what, does everyone on this site

    type a complex reply in 57 seconds!!!! (this hasn't happened before, just the last couple days)
    Reply With Quote  
     

  6. #6  
    Senior Member
    Join Date
    Jul 2014
    Posts
    115
    Particles make of quark,right? So what quark make graviton and photon
    Reply With Quote  
     

  7. #7  
    Senior Member
    Join Date
    Jun 2014
    Posts
    551
    Quote Originally Posted by johnzxcv View Post
    Particles make of quark,right?
    No. Only a certain class of particles called hadrons are made of quarks. Hadrons come in two forms, baryons (such as protons and neutrons which are made of three quarks) and mesons (such as pions which are made of a quark and an antiquark). See Hadron - Wikipedia, the free encyclopedia
    Reply With Quote  
     

  8. #8  
    Senior Member
    Join Date
    Jul 2014
    Posts
    115
    Quote Originally Posted by Physicist View Post
    No. The particle that mediates the electromagnetic force is the photon and that which mediates gravity is the graviton. Since each of these is an inverse square law these particles have zero mass. However the force that mediates the strong force is not an inverse square law. It drops off much faster (i.e. does not have the same functional form) than an inverse square law. The potential function for the strong force is the Yukawa potential. The particle which mediates this force therefore has mass and therefore the speed of the interaction should be less than the speed of light.
    Then how fast is the strong nuclear force?
    Reply With Quote  
     

  9. #9  
    Senior Member
    Join Date
    Oct 2013
    Location
    UK
    Posts
    997
    Quote Originally Posted by Jilan View Post
    They are known as pi mesons or pions for short.
    Pion - Wikipedia, the free encyclopedia
    The pions mediate the residual strong force, which is the force between nucleons. The real strong force between the quarks is mediated by gluons. These are massless so the force will propagate at c. I'm not sure about the residual nuclear force though.
    johnzxcv likes this.
    Reply With Quote  
     

  10. #10  
    Senior Member
    Join Date
    Jun 2014
    Posts
    551
    Quote Originally Posted by Jilan View Post
    The pions mediate the residual strong force, which is the force between nucleons. The real strong force between the quarks is mediated by gluons. These are massless so the force will propagate at c. I'm not sure about the residual nuclear force though.
    Ooooo!! Great point. I never thought about that. Let me think about it and get back.
    Jilan likes this.
    Reply With Quote  
     

  11. #11  
    Senior Member
    Join Date
    Jul 2014
    Posts
    115
    Quote Originally Posted by Physicist View Post
    Ooooo!! Great point. I never thought about that. Let me think about it and get back.
    So speed of strong force is c?
    Reply With Quote  
     

  12. #12  
    Senior Member
    Join Date
    Jul 2014
    Posts
    115
    Quote Originally Posted by Physicist View Post
    No. The particle that mediates the electromagnetic force is the photon and that which mediates gravity is the graviton. Since each of these is an inverse square law these particles have zero mass. However the force that mediates the strong force is not an inverse square law. It drops off much faster (i.e. does not have the same functional form) than an inverse square law. The potential function for the strong force is the Yukawa potential. The particle which mediates this force therefore has mass and therefore the speed of the interaction should be less than the speed of light.
    You said particle that mediates the electromagnetic force is the photon.Than what particle mediates the force between charge?
    Reply With Quote  
     

  13. #13  
    Senior Member
    Join Date
    Oct 2013
    Location
    UK
    Posts
    997
    The photon.
    johnzxcv likes this.
    Reply With Quote  
     

  14. #14  
    Senior Member
    Join Date
    Jul 2014
    Posts
    115
    Quote Originally Posted by Jilan View Post
    The photon.
    You mean particle with charge fire photon.
    Reply With Quote  
     

  15. #15  
    Senior Member
    Join Date
    Oct 2013
    Location
    UK
    Posts
    997
    That's sort of the picture, but the photons are virtual. Here is a good link that talks about virtual particles and forces.
    Some Frequently Asked Questions About Virtual Particles
    johnzxcv likes this.
    Reply With Quote  
     

  16. #16  
    Senior Member
    Join Date
    Jul 2014
    Posts
    115
    Quote Originally Posted by Jilan View Post
    That's sort of the picture, but the photons are virtual. Here is a good link that talks about virtual particles and forces.
    Some Frequently Asked Questions About Virtual Particles
    Thanks.
    I understand now.
    How about the weak force. Does it's speed equal c?
    Reply With Quote  
     

  17. #17  
    Senior Member
    Join Date
    Oct 2013
    Location
    UK
    Posts
    997
    That force is mediated by the W and Z bosons.
    W and Z bosons - Wikipedia, the free encyclopedia
    These are heavy particles so only act over a short range. They have mass so will not travel at c.
    Reply With Quote  
     

  18. #18  
    Senior Member
    Join Date
    Jul 2014
    Posts
    115
    Quote Originally Posted by Jilan View Post
    That force is mediated by the W and Z bosons.
    W and Z bosons - Wikipedia, the free encyclopedia
    These are heavy particles so only act over a short range. They have mass so will not travel at c.
    I want to know how fast are they?
    Reply With Quote  
     

  19. #19  
    Senior Member AlexG's Avatar
    Join Date
    Jan 2013
    Posts
    161
    Since their half lives are 310−25 s, they don't travel fast or far.
    Reply With Quote  
     

  20. #20  
    Senior Member
    Join Date
    Jun 2014
    Posts
    551
    Quote Originally Posted by AlexG View Post
    Since their half lives are 310−25 s, they don't travel fast or far.
    More to the point, it's not possible, neither in theory nor in practice, to measure the speed of such a particle. Velocity has no meaning at the quantum level. That's something a lot of people don't understand about quantum theory. There's really no such thing as a velocity operator. Some people like to think of the operator V = P/m where p is the momentum operator and m the particles mass as a velocity operator. However the problem with this is that P is conjugate momentum and not the mechanical momentum mv.
    johnzxcv likes this.
    Reply With Quote  
     

Posting Permissions
  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •