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Not a singularity, just much more dense. If current indications are correct, the universe has always been infinite. On current theory, how fast is a galaxy at say 50 billion light years thought to be moving, relative to us. George ? I  ask because clearly on Hubble's (velocity) Model, it should be moving a lot faster than light eh! ! I assume you mean a galaxy that is separated by that distance over a surface of equal cosmological age. There is an excellent explanation of this subject at:   http://www.astro.ucla.edu/~wright/cosmo_02.htm#MD Ned says on that page: The time and distance used in the Hubble law are not the same as the x and t used in special relativity, and this often leads to confusion. Your question is a perfect example. A little further down the page, he says In these variables, velocities greater than c are certainly possible, and since the open Universes are spatially infinite, they are actually required. But there is no contradiction with the special relativistic principle that _object_s do not travel faster than the speed of light . That is followed by a graph that answers your question far better than I ever could. HTH George

A little further down the page [...] . In these variables, velocities greater than c . are certainly possible [...] ... at least given how the values of GR velocity v and GR distance D appear in the Hubble law , and if there are indeed values D_exc( t ) in the range of the GR distance definition such that H D_exc( t ) = d/dt( D_exc( t ) ) c for suitable values H; while OTOH for pairwise distances x( t ) measured through the procedures of special relativity holds d/dt( x( t ) ) < c, of course. Ned Wright states some further properties of the GR distance D which imply more directly, without involving the Hubble law , that values of D cannot in general be defined and measured through the SR procedures (as values x ). After all, I'm not primarily concerned with the applicability of any particular Hubble law , but instead with which, if any, reproducible measurement procedures of GR are being used to define the quantities (e.g. values of coordinate relations) in terms of which any laws can be stated in the first place. . The distance in the Hubble law must be defined so that . if A and B are two distant galaxies seen by us . in the same direction, . and A and B are not too far from each other, . then the difference in distances from us, [... . D_{ Us_now }_( B, Us ) - D_{ Us_now }_( A, Us ), . notation consolidated - FW] . is the distance A would measure to B. . But this measurement must be made now

That is followed by a graph [...] (again at http://www.astro.ucla.edu/~wright/cosmo_02.htm#MD). The second graph on that page shows explicitly . surfaces of constant proper time since the Big Bang each of which apparently identifies a set of individual states ( nows ) on distinct worldlines that correspond to each other through a calibration procedure. Again: How is such (pairwise) calibration to be measured, in GR ? Through which procedure would proper time since the Big Bang be defined and measured in GR, for distinct worldlines, in order to be compared ? Thanks again,        Frank  W ~@) R

(again at http://www.astro.ucla.edu/~wright/cosmo_02.htm#MD). The second graph on that page shows explicitly . surfaces of constant proper time since the Big Bang each of which apparently identifies a set of individual states ( nows ) on distinct worldlines that correspond to each other through a calibration procedure. Again: How is such (pairwise) calibration to be measured, in GR ? Through which procedure would proper time since the Big Bang be defined and measured in GR, for distinct worldlines, in order to be compared ? I am sure you can find many references on the web that explain how the age of the universe is determined. An observer on each worldline applies that or an equivalent method. The Hubble 'D' is measured along the surface containing events where the independently determined values are the same.

followups to sci.astro and sci.physics.relativity only. keithstein < This e-mail address is being protected from spam bots, you need JavaScript enabled to view it wrote in message George Dishman < This e-mail address is being protected from spam bots, you need JavaScript enabled to view it wrote in message keithstein < This e-mail address is being protected from spam bots, you need JavaScript enabled to view it wrote in message Thanks for commenting on my essay George. No problem Keith. It was generally reasonable so I thought it useful to clear up the few minor misunderstandings of what present theory predicts. I take it you agree with my comments. Well i certainly agree with your very first comment George, and the rest i thought generally reasonable too, but you didn't convince me there really was a Big Bang eh! keith stein

didn't convince me there really was a Big Bang eh! Fine, I wasn't trying to.