marcus/pete,
Guys, thanks, very interesting, I was unware of this semantics issue surrounding the word 'mass', I am an not a physicists , just someone with an interest due to my work in financial markets...don't ask! ( yeah, i have a physics degree 15 years ago, but the details get forgetten!).
I found these article very useful on this semantics discussion:
http://math.ucr.edu/home/baez/physics/Relativity/SR/mass.html And
http://math.ucr.edu/home/baez/physics/Relativity/SR/light_mass.html
Here is a relavent quote from the links
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"There is sometimes confusion surrounding the subject of mass in relativity. This is because there are two separate uses of the term. Sometimes people say "mass" when they mean "relativistic mass", mr but at other times they say "mass" when they mean "invariant mass", m0. These two meanings are not the same. The invariant mass of a particle is independent of its velocity v, whereas relativistic mass increases with velocity and tends to infinity as the velocity approaches the speed of light c. They can be defined as follows:
mr = E/c2
m0 = sqrt(E2/c4 - p2/c2)
where E is energy, p is momentum and c is the speed of light in a vacuum. The velocity dependent relation between the two is
mr = m0 /sqrt(1 - v2/c2)
Of the two, the definition of invariant mass is much preferred over the definition of relativistic mass. These days, when physicists talk about mass in their research, they always mean invariant mass. The symbol m for invariant mass is used without the subscript 0. Although the idea of relativistic mass is not wrong, it often leads to confusion, and is less useful in advanced applications such as quantum field theory and general relativity. Using the word "mass" unqualified to mean relativistic mass is wrong because the word on its own will usually be taken to mean invariant mass. For example, when physicists quote a value for "the mass of the electron" they mean its invariant mass.
At zero speed, the relativistic mass is equal to the invariant mass. The invariant mass is therefore often called the "rest mass". This latter terminology reflects the fact that historically it was relativistic mass which was often regarded as the correct concept of mass in the early years of relativity. In 1905 Einstein wrote a paper entitled Does the inertia of a body depend upon its energy content?, to which his answer was "yes". The first record of the relationship of mass and energy explicitly in the form E = mc2 was written by Einstein in a review of relativity in 1907. If this formula is taken to include kinetic energy, then it is only valid for relativistic mass, but it can also be taken as valid in the rest frame for invariant mass. Einstein's conventions and interpretations were sometimes ambivalent and varied a little over the years; however an examination of his papers and books on relativity shows that he almost never used relativistic mass himself. Whenever the symbol m for mass appears in his equations it is always invariant mass. He did not introduce the notion that the mass of a body increases with velocity--just that it increases with energy content. The equation E = mc2 was only meant to be applied in the rest frame of the particle. Perhaps Einstein's only definite reference to mass increasing with kinetic energy is in his "autobiographical notes".
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My original question needs to be refined into a set of more detailed questions, and i'll be as semantically clear as i can!:
1. What causes invariant mass at an elemental level ?
Inertia - yes, but that is too high a level of abstraction i.e. What is inertia?
I researched this and said the answer i found was inertia( and hence invariant mass) is the result of the Higgs fields, i have some links in previous posts, and here's an excellent article in scientific america:
http://www.sciam.com/askexpert_question.cfm?articleID=00043456-7089-1C71-9EB7809EC588F2D7
"One major ingredient in this model is a hypothetical, ubiquitous quantum field that is supposed to be responsible for giving particles their masses (this field would answer the basic question of why particles have the masses they do--or indeed, why they have any mass at all). This field is called the Higgs field. As a consequence of wave-particle duality, all quantum fields have a fundamental particle associated with them. The particle associated with the Higgs field is called the Higgs boson. "
2. Can invariant mass be converted to energy, and energy to invariant mass?
Yes, invariant mass to energy occurs in fission/fusion.
Energy to invariant mass occurs in nature and forced particule accelerator experiments.
I'm sure if i have got something incorrect someone will tell me! thanks.
BUT - This still leaves me where i started though, and let me rephrase the question:
What are Photons 'made of', what are 'quarks made of'. Take all the lowest level elemental particles - either 'real' or 'virtual', and ask 'what are they composed of'. They must be made of something, what is it?
I have trouble accepting the idea that one can ever stop 'sub dividing and decomposing', since you can chop a quark in half etc or if you do that, do you get two smaller quarks?
Whilst science cannot answer why question, we surely should be able to answer the 'what questions' as in, what is a fundamental particle made of. This gets trickier of course since really the both waves and particles - so that needs explaining too. I've read a little of string theory - but all physics seems to do is move the issue from one elemental element to another - the question remains, what these are made of too.
My specific interest is to know if fractals behaviour shows up at an elemental level, since it shows up at higher levels everywhere in nature, but that's getting ahead of myself here. Completely unscientifically!, i propose that the elemental level must exhibit fractal properties.
The ultimate question I'm research is the issue of determinism versus chance - i'd hoped that elemental physics would reveal some answers. I'm aware of the uncertainty principle, but that's a measurement problem - it doesn't answer whether 'randomness' is a built in feature of our universe or just a built in feature of our ability to measure it.
Has the determinism debate been settled? Hawking implies it has, saying that were close to having all the elemental elements etc But, then fractal behaviour must be explainable, and all other natural observable phenomena that appears to exhibit an 'element of chance' - in essense, randomness would not exists, there would be cause for all things - and of course, humans themselves would just be predicable with no free will.
Any useful links on this appreciated, I'm sure this discussion exists somewhere i can look at.
