PS: A couple more thoughts on redshift and Hubble acceleration:
1. Since deep past light cones are curved inward it seems to me that standard candle objects in the deep past would appear slightly smaller than they should be if the universe had not expanded because their light rays pinch inward as they get to us. That means that (unless this is corrected for) that deep past objects are actually less distant than they appear (since they are actually slightly larger than they appear) and thus that the red shifts we associate with deep past objects are actually those for slightly less distant objects. That would mean that the acceleration of the Hubble expansion might be LESS than we think, because the redshifts of nearer objects are greater than we thought and thus nearer to those even closer, meaning that the redshift (and thus the Hubble expansion) doesn't vary as much with time and distance as was thought. Whether that is enough to eliminate the putative acceleration I don't know, that would have to be worked out, but it would diminish the acceleration some. 2. Again however the basic problem is that we can measure standard candle redshifts for only 1 point of time at each point of distance. So the best we could possibly claim is that CLOSER distances of the universe seem to have been accelerating faster millions of years ago than FAR distances of the universe were billions of years ago. All the rest is assumptions.... Edgar On Friday, January 31, 2014 8:19:41 AM UTC-5, Edgar L. Owen wrote: > > All, > > It seems to me there are some somewhat questionable assumptions here based > on a very restricted data set. > > First, the presumed acceleration of the Hubble expansion is based on the > varying redshifts of standard candles such as type 1a supernovas with > distance and time. > > The basic problem with this is that we observe past times only at > particular distances, and equivalently distances only at particular past > times. So we have to assume that > > 1. At all past times, the universe at all distances was expanding at the > same rate that we can observe it expanding only at a SINGLE distance. > 2. That the apparent sizes of things (1a's) recedes LINEARLY with both > time and distance over the entire history, and entire expanse of the > universe. In other words that there is no type of large scale spacetime > curvature that would result in a slightly NONlinear decreases or increases > in apparent size over the expanse and history of the universe. > 3. That there is no alternative cause of red shift other than relative > velocity (specifically when it comes to evaluating 1a's for which we can > eliminate or account for gravitational redshifts). In particular that > enormous time and distance per se have no effect on EM frequencies. > > Thus the initial but unverifiable assumption is that the universe expanded > at the same rate everywhere at any given time. However we actually have > absolutely NO IDEA of how fast it is actually expanding right NOW because > we cannot measure what it is doing right now because we have to wait for > the light to reach us. We can only measure what what it was doing at > various past times and then only at particular distances. So right now the > distant universe could well be collapsing or exploding and we would have > absolutely no knowledge of that. So we simply cannot say with any certainty > at all that 'the Hubble expansion is accelerating' right NOW. > > Also we know (or assume) that the early universe was significantly SMALLER > than the current universe since it has been expanding continuously. In > other words galaxies must have been significantly CLOSER together back then > even though we see them distributed all around the galactic sphere as if > they are not. > > This produces a type of illusion of scale when we look back into the > universe. The problem is that into the distant universe and back into > distant time the sides of our light cones are not straight but CURVED, > because they must eventually all converge at the big bang towards a single > point (if we could see back that far) rather than continuing to expand in > straight lines back into time as they are usually depicted. > > Now it seems to me this might cause some non-linear effect of red shifts > or apparent sizes of distant 1a quasars which would affect the calculations > of Hubble expansion rates over time. > > Is anyone familiar with this argument and able to comment on the > implications? > > Thanks, > Edgar > -- 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 post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/groups/opt_out.
