Subject: Resubmitted: What is the current explanation of mass and inertia?

Hi.
I am at Leeds university (England) studying physics and astrophysics. I am 
curious to know as to why a object will have mass and inertia. Why does a body 
with mass attract other bodies of mass? Why does a body with mass also have 
inertia? Why does the gravitational constant remain the same for all bodies of 
mass? Does all matter have mass and is all mass matter? Light can have momentum 
and is effected by gravity. Could mass therefore be the interaction of charged 
particles within a object and the particles/photons flashing in and out of 
existance in the quantum vacuum? Thus making inertia related to the 
electromagnetic force which would act as a frictional force? However unless 
these quantum fluctuations become polarized, I do not know how this would 
account for the attractive force we call gravity. 
I look forward to any replies.
Regards
William Flewitt 

Re: Resubmitted: What is the current explanation of mass and inertia?