Posted: May 03, 2010 3:00 am
Presumably the expansion of the universe imposes a continuous stretching force on matter. (And because we now know the expansion is accelerating, that force must be increasing.) The known physical forces must pull against this, maintaining atoms and macroscopic objects at their present size. Does this have any energy consequences? Is work done, entropy increased, the energy content of the universe altered by this process?
Expansion also reduces the frequency, and therefore the energy, of radiation in intergalactic space: light, CMB, etc. Presumably this is an energy loss for the universe.
And expansion also means that the gravitational potential energy between distant objects is increased, without (it seems) a corresponding decrease in kinetic energy. So that would seem to increase the energy in the universe.
Are those effects real? What are their relative magnitudes? What is the nett effect and does it have any interesting implications?
Expansion also reduces the frequency, and therefore the energy, of radiation in intergalactic space: light, CMB, etc. Presumably this is an energy loss for the universe.
And expansion also means that the gravitational potential energy between distant objects is increased, without (it seems) a corresponding decrease in kinetic energy. So that would seem to increase the energy in the universe.
Are those effects real? What are their relative magnitudes? What is the nett effect and does it have any interesting implications?