><snip> Except that the expansion of the Universe is so fast that this is not possible.
>
>Is it the increased photon & in fact all radiation densities that is causing the accelerative expansion ?
Look up "dark energy" on Wikipedia. Basically:
There is consensus that the expansion of the Universe is, indeed, accelerating.
Several alterantive theories are being proposed; usually something similar to a "cosmological constant" that permeates space - that can be thought of as a property of space itself.
Also take a look at "metric expansion of space" - there is a consensus that somehow, "space itself" is expanding, whatever that means, it is not just the galaxies that are moving through space.
So, it is definitely not due to radiation - the "dark energy" is something of yet unknown composition. It is generally believed that the Universe consists of the following masses or energies:
4% - known matter and energy. This includes, stars, radiation, intergalactic dust and gas, and even black holes.
23% - a mysterious "dark matter". For example, galaxies rotate way too fast for the known matter they contain - but it is not yet known of what kind the missing matter is. Something that hardly interacts with radiation.
73% - the "dark energy" that is producing the increase in the expansion rate of the Universe.
Difference in opinions hath cost many millions of lives: for instance, whether flesh be bread, or bread be flesh; whether whistling be a vice or a virtue; whether it be better to kiss a post, or throw it into the fire... (from Gulliver's Travels)
