On Saturday, July 19, 2025 at 11:11:27 PM UTC-6 Liz R wrote:
I suspect you're conflating two vastly different things? Light from distant galaxies - what's used to measure the Hubble constant - was emitted WAY after the hypothetical inflationary era. *No; I'm definitely not conflating the hypothetical inflationary period, which is conjectured to have occurred (and concluded) during the first second after the BB, whereas galaxy formation occurred after 380,000, when the CMB manifested. AG* The Hubble expansion only refers to the increasing separation between galaxies/clusters of galaxies/similar observable objects/groups. It isn't possible to make deductions about inflation (except indirectly, e.g. from the observed homogeneity of matter in the universe) from observable objects, which formed a lot later. *I made no deductions about inflation. Rather, I am confused why Clark claims the red shift observed today from ancient galaxies, is consistent with SLOW cosmic expansion at that time, when it's generally accepted that the red shift we measure today left those galaxies well in the past, and AFAIK, has always been interpreted as due to expansion of the cosmos. It's obvious that in ancient times galaxies were much more closely separated than presently, but Clark ALSO claims the rate of expansion was small at that time. The red shift of those galaxies seems to indicate otherwise, although this high rate of expansion is small compared to inflation, which was (if it occurred) much faster than light speed. AG* The earliest directly observable thing in the universe (at present) is the microwave background. It's possible neutrinos or gravitational waves will let us observe earlier eventa, but none of these appraoch the inflationary era, which predates the quark-gluon plasma that became nuclei etc. On Tuesday, 15 July 2025 at 14:30:28 UTC+12 Alan Grayson wrote: Given the fact that light from very distant galaxies is hugely red-shifted, and the general belief that light we're observing today from those distant galaxies, was emitted when the universe was very young, one would conclude that the rate of expansion at that time was huge. But Clark disputes this conclusion. He claims the opposite; that the rate of expansion in the very early universe was exceedingly SLOW. If that's the case, can we conclude that the theory of Inflation must be false, insofar as it alleges a huge initial expansion rate to account for the observed uniformity of the current universe? Moreover, Hubble's law confirms that as we go back in time, the universe was expanding faster than it is today, again apparently confirming the Inflation theory of a very high initial rate of expansion (ignoring recent findings the the rate of expansion is iagain ncreasing). AG -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion visit https://groups.google.com/d/msgid/everything-list/2203c306-558a-4855-9362-b647a1136e66n%40googlegroups.com.
