Light and Matter (Origins)

by dhw, Tuesday, May 27, 2014, 18:49 (3831 days ago) @ David Turell

Dhw: Why is this experiment so important?
DAVID: It proved a theoretical proposition from many years earlier.-The experiment hasn't yet taken place. It aims to prove that matter can be made from "pure light". One scientist remarks: "It's breathtaking to think that things we thought are not connected can in fact be converted to each other: matter and energy, particles and light." Another says "matter and energy are interchangeable currencies." But until the experiment has succeeded, presumably this so-called interchangeability has NOT yet been proven, and nor has the ability of "pure" light/energy to be converted into matter. This brings us to the second point:
 
dhw: Earlier you wrote: "Technically one can call each particle a matter particle; each particle being a tiny bit of matter. The confusion is that one thinks of them as pure energy, and they are pretty close to that." And my question remains: is there such a thing as pure energy? "Pretty close to" does not = pure. -DAVID: It [the confusion] comes from the problem of definition. the research has shown that everything started with pure plasma energy. When one wants to start calling it matter is by human definition. Mine, which has always been after the development of the particle phase, may not be correct by some standards. Makes no difference to the overall concept. All matter is energy in a more solid form.-As a non-scientist I can only compare what you tell me with what I discover from other sources. If it boils down to definition, there seems to be no such thing as "pure energy" unless someone wants to call it pure ... as you have done so far with plasma, photons and electrons, all of which have been defined elsewhere as matter. We know matter contains and produces energy, but do we know that energy creates matter? Perhaps at best (if I've understood the terms of the forthcoming experiment) it might produce short-lived, subatomic, invisible particles of matter that we would not equate with the solid, liquid or gaseous stuff we normally understand by the term. How does this make energy and matter "interchangeable"?-Dhw: [...] let me first ask you directly whether, in view of all the above, you yourself do or do not find the so-called interchangeability of energy and matter confusing.
DAVID: Not at all.-Am I right, then, in supposing that your confidence relates to a concept of "pure energy" that is based on subjective definition plus faith in an as yet unproven theory? (Again, this is a genuine question, not an argument.)