Quote:
Originally Posted by Squashed
Here it is stated that the universe began as "pure energy" yet when I try to nail down an elemental entity from which all of matter is derived posters like Celestial Mechanic adamantly state that matter can not be derived from photons (due to considerations of spin, charge, etc.).
Here the mention of " photon-photon" collisions are invoked to explain the creation of matter from photons but then no explanation of how the momentum changed from expanding purely radial photons (no collision possible) to a momentum state that allows such photon-photon collisions to occur. (remember my Big Bang Momentum thread?)
It would be nice if these things were tied together cohesively to allow one to understand all these seemingly contradictory conditions. |
There are many ways this cohesive tying together could be done; here's one suggestion:
Start with GR - establish common understanding of the bare basics, sufficient to handle what is needed later.
Apply GR to the universe - see how that results in an expanding universe; do this with the absolute minimum of math.
Discuss what these GR solutions have to say about the nature of mass-energy which the universe (in such solutions) comprises.
Relate the (general) nature of the (GR) mass-energy to what we commonly understand to be mass and energy (this is a transition stage).
Review the Standard Model, in terms of the mass-energy entities it contains.
Close the discussion, by tying the mass-energy in GR to the mass-entities in the Standard Model.
The advantage of this approach is that it starts with
mugaliens' question, and with the primary (physics) theory relevant to cosmology (GR).
The disadvantage is that the minimum math to get to stage three may take us several months ...
Thoughts?