[continued from previous message]   
      
   >>>>> for parts of the universe that are no longer visible to us.  Space   
   >>>>> expanded and nothing really accelerated to faster than light, but they   
   >>>>> are just too far away to observe.  There was the initial inflation when   
   >>>>> space expanded much faster than the speed of light creating a "flat   
   >>>>> universe" with just the right amount of mass and energy to keep it from   
   >>>>> collapsing.  Dark energy is supposed to account for the continued   
   >>>>> expansion of space within the universe.  One article that I recall   
   >>>>> claimed that the visible universe extends out to around 45 billion light   
   >>>>> years in all directions from where we are.  The visible light has to be   
   >>>>> younger than the age of our universe (less than 14 billion years), but   
   >>>>> space has expanded.   
   >>>>   
   >>>>   
   >>>> An important point is, according to the evidence, there was a time   
   >>>> before about 4bya when the universe was dominated by gravity, and its   
   >>>> rate of expansion was actually slowing.  Now the universe is dominated   
   >>>> by dark energy, and so its rate of expansion has become ever faster   
   >>>> since then.   
   >>>   
   >>> The claim in the article is that the expansion of the universe continues   
   >>> to be currently accelerating, but the rate of acceleration is   
   >>> decreasing, so dark energy effects seem to have limits.   
   >>    
   >>    
   >> What you say above is contrary to what I have read:   
   >>    
   >> ********************************   
   >> In 1998, the High-Z Supernova Search Team published observations of   
   >> Type Ia ("one-A") supernovae. In 1999, the Supernova Cosmology Project   
   >> followed by suggesting that the expansion of the universe is   
   >> accelerating. The 2011 Nobel Prize in Physics was awarded to Saul   
   >> Perlmutter, Brian P. Schmidt, and Adam G. Riess for their leadership   
   >> in the discovery.   
   >> ********************************   
   >>    
   >>    
   >>> I recall an article claiming that our current visible universe extended   
   >>> out to around 45 billion light years in any direction (maybe it was 45   
   >>> billion light years across, the light within visible space has to be   
   >>> less than 14 billion years old) but there has to be a lot of the   
   >>> universe that we can no longer see.  Kestrel indicated that this limit   
   >>> applied to the points within our visible universe so that every location   
   >>> had a different horizon and could see a different part of the existing   
   >>> universe.  There would have to be a lot of matter that is not in the   
   >>> visible universe.   
   >>    
   >>    
   >> Correct.  This is something I pointed out to Peter Nyikos awhile ago,   
   >> and I pointed out to you in my last post.  Every point in the cosmos   
   >> is surrounded by its own Hubble Sphere.  The working assumption is   
   >> that the cosmos outside our Hubble Sphere is largely similar to the   
   >> space inside.  The problem is there is no way to know this for   
   >> certain, even in principle.   
   >>    
   >>    
   >>> Ron Okimoto   
   >>>>   
   >>>>   
   >>>>> It doesn't matter, what I wanted was if the mass of the universe   
   >>>>> estimate includes the mass that is not observable.  We have the   
   >>>>> background radiation map of the universe, and estimates based on what we   
   >>>>> can see (these are based on the observable universe).  The estimates   
   >>>>> would have included what we could not see within the visible universe   
   >>>>> because we lacked the ability to detect the light from the distant   
   >>>>> objects.  Did this estimate also include the mass that was too far away   
   >>>>> to be visible?  How do we know how much mass is no longer visible and is   
   >>>>> beyond the horizon of what we can see?  We've been trying to estimate   
   >>>>> the amount of dark matter within the visible universe, so how would we   
   >>>>> measure the amount of matter further away than the visible horizon?   
   >>>>> Even though we can't observe it, it is still part of our universe.   
   >>>>>   
   >>>>> Ron Okimoto   
   >>>>   
   >>    
   >Good advice regarding the reliability of social media such as Facebook    
   >or this forum for that matter.  Best to check to primary sources.  Some    
   >popular outlets are reliable, some not.   
      
      
   Some consider Wikipedia "social media, which I cited, and consider to   
   be at least as reliable as other collections of facts.  I agree the   
   above case illustrates a challenge when citing rapidly-changing   
   sources, in this case Facebook.  I was unable to read/listen to RonO's   
   original cite, so I could not determine what his source material   
   actually said.  I would be very surprised if any current source said   
   there was evidence that the universe's expansion rate was slowing   
   down.   
      
   --    
   To know less than we don't know is the nature of most knowledge   
      
   --- SoupGate-DOS v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)