Helio, in addition to #65, I think I have even more problem with the idea of a Universe expanding faster that the speed of light - OK just space expanding, but it seems to me that we are getting back to the old idea of aether? Space/time expanding ~~~ aether as an expandable medium?
Yeah, the aether idea never completely vanished. People think it died when Einstein dismissed it but Einstein only said that no medium (ie aether) is necessary for light propagation; not that aether doesn't exist. [The Hubble Flow is particularly interesting as a possible springboard to work from.]
Given the BBT, space has done a great deal of expanding since that first moment, so more expanding, however that happens, seems easily justified. The hard part was determining if there was enough objective evidence for BBT because implications, like a continued expansion (and acceleration), have been tough pills to swallow for many. The brilliant Hoyle, though he supported the science that helped BBT, never accepted BBT as he always had hopes his, and other's, Steady State Theory, or modifications to it, would prove more favorable.
[Speaking of Hoyle, I finished a book that included the author's suggestions why Hoyle -- arguably the Father of stellar nucleosynthesis -- never received the Nobel prize. Interested?
P.S. space/time expanding but not the space occupied by mass?? Expansion of space/time checked by the presence of mass??
Local space is expanding but it is an incredible tiny amount over only millennial scales, so that gravity is more than sufficient to reign-in any such spacetime expansion.
Perhaps, and maybe someone smarter will respond to this idea, we could simply note that as space expands it does add or subtract angular momentum from orbiting planets. So if the angular momentum is unchanged, so too will be its orbital distance, at least I think I'm right.
So. IF the Universe contracts, does the increasing density correspondingly promote decrease in entropy??
Is there an analogy you can use to help me see this? We both know gasses, when compressed, are essentially irreversible, so entropy increased, but a Universe?
The whole idea rests on the premise that the Universe can flip into contraction??
Yes, this idea would be a bit bizarre if it weren't for the fact we really have no idea what DE is.
To me, the idea of beginning/end is anathema - anthropocentric delusion.
You're not alone.
When Lemaitre introduced his theory, a "beginning", matching the words of Genesis, had strong religious implications, of course, though some religions claim no beginning. Initially, Einstein refused to accept the idea that the universe wasn't always the same. But back then there were no galaxies, only nebulae, and there was little evidence for expansion, only a few dozen redshifts from Slipher. Eddington and deSitter, and others, seem to win Einstein over to Lemaitre's work once the problems with the Static Model failed.
It's worth noting the BBT (Lemaitre) came mainly from Einstein's theory, GR, and not scientists trying to figure out some new discovery that had no explanation. This doesn't happen very often, and for it to be true of the biggest theory of all is remarkable to me.
We should not expect conclusions based on a system dependant on our limited sensory input to govern the workings of the Universe. In particular, consideration of semantics - vide Universe v. observable universe(s).
I partially agree for the reason that no theory offers proof it is immutable. But when the abundance of objective evidence supports the claims made, and engineers are given the "laws" (e.g. GPS work) that do prove effective, it's hard to expect anything but respect for it.