🚀 go-pugleaf

In article  <sehari.724010247@class1.iastate.edu> , Babak Sehari writes

>Well after learning years of physics, I have no idea why two objects
>at a distance feel each others gravitational force, or for that mater
>why two charges at a distance can feel each other? ( I know How they
>do it ie. newton and coulomb law, but why they do it? )

  You can`t ever answer the question why like that . Even if we had a
perfect axiomatic system describing the universe ( multiverse ? ) ,
you could still ask why axiom A holds. The Quantum Electrodynamics 
answer to the above question is , that charge fields have an internal
degree of freedom which is guage invariant and this gives rise to a
field ( of photons ) , that causes the quanta of the charged field
to move as if acted upon by a force .(Sorry thats a very poor
expansion of QED , I`am only a grad student in statistical mechanics ).
The maths works out beautifully , but you can still ask the question,
why do these fields have an internal degree of freedom .
  One answer to such why questions that I like is, that all internally
consistent universes exist , we just happen to be in this one .

>I know the charge disturbance propagate by photons with the speed of light,
>as has been formulated by maxwell? But what about two masses, how does the
>gravitational field changes propagates in the space? How fast does that
>travel? 

  Well if quantum gravity worked i`d say that the gravitational field
propagates as gravitons moving at light speed . However since a working
quantum gravity theory hasn`t been found , i`ll have to say gravitational
field changes don`t propagate in space , they are space time which obeys
Ensteins equation, and thus have in fixed thoughout space-time to behave
as we see . This is taking General Relativity literally . Gravitational waves
however can be said to propagate at light speed,  

>What is charge, why is it that we have Positive & negative charges, and
>why the smallest unit of positive charge is equal to smallest unit of
>negative charge? ( do not give me electron and proton story, my question
>here is why electron has negative charge and proton has positive charge
>of exact opposite magnitude) Why an electron can not have twice the charge?

  Anthologically , if electrons and protons didn`t have exactly equal and
opposite charges matter wouldn`t be stable and we couldn`t exist .
Another answer is that when quarks and electrons are grand unified the possible
charges of the particles in one group must add to zero , thus for example SU(5)
                       (3u , 3d , e- , v )
charges are           3*2/3 + 3*-1/3 -1 + 0 = 0

  There are only a small number of ways of forming a group like this and it
follows that all particles charges must be simple multiples of each other.

>For that mater why it can not be found with 1.5 times the charge?  Why negative
>charge attaches to smaller mass than positive charge?

  This is an convention , the world would be exactly the same if a positive charge
was found on elections , muons etc and a negative one on protons.

>  Does Anti-mater exists?

   Yes , they have been making the anti protons for years at CERN and I believe
they have even stored anti-hydrogen in atom traps for short periods of time .

>that is can we attach negative charge to nucleus of matter?  What is causing
>negative charge property, why should be attracted to creator of positive charge
>property and repeals from negative charge?

   I behave , like charges repelling and unlike charges attracting may be derived
form the spin statistics of the photons in QED . 

>What is causing the magnetic force, that is why spin of a charge in one
>direction influences other charge spins?  Why does not natural mass spin
>generate similar effects? ( What causes the Amper's law, or the Lenses law)

   The magnetic force is derived in the same way as the electric force . Indeed
they are the same thing looked at form different perspectives . An electric field
seen by one obverser may be viewed as both an electric and magnetic field by
a second obverser moving wrt to the first obverse . 
I`m not quite such of my general relativity on the question of a spinning mass
but i seem to recall the a spinning black hole does indeed give rise a to force
differing form a static one . In normal circumstance such a `gravimagentic force`
would be completely negligable however .
 
>Lets answer them one at the time.

  I hope i have , in so much as why questions can ever be answered.

This is my first posting to sci.physics so don`t flame too hard if I`am compleatly
missguided.

Barry Adams , bdoa@ukc.ac.uk , posting from bdoa@access.digex.com