Light Cone - Hubble Radius & Time T and R Relationship

In summary: I'll try to see if I can simplify this equation a bit (for the flat case). But it looks like the approximate formula I was remembering.You can see that this approximation would only work (or work best) when dark energy is small compared to matter (and radiation.) So at late times it would not work well, as I recall.At early times probably matter dominated, and it would not work as well.But I'm not sure. It is just an approximate formula. Jorrie would know more about it. Maybe he could say more here.In summary, the conversation discusses the relationship between T (age of the universe) and R (Hubble radius) in a flat universe consisting of matter and
  • #36
The closest logistic model i could calculate was
16.997769517/(1+35.79253791478e^-.6025402362228t)

Ok but certainly not satisfying.
Where t is in billions of years
 
Space news on Phys.org
  • #37
Ledsnyder said:
The closest logistic model i could calculate was
16.997769517/(1+35.79253791478e^-.6025402362228t)

Ok but certainly not satisfying.
Where t is in billions of years

I think George's solutions (posts 13 and 7) do much better, because for most of U's history, radiation energy density has been negligible compared to the other forms. It hence gives R_Hubble with great precision back to the epoch where stars/galaxies were formed (also as far as you wish into the future)
 
Last edited:
  • #38
Jorrie,your calculator is awesome.i wish there was similar to calculate complex curves I general that don't neccesarily deal with the universe.
 
  • #39
Ledsnyder said:
i wish there was similar to calculate complex curves I general that don't neccesarily deal with the universe.

Try http://graphsketch.com/, a free graph plotter with quite a lot of flexibility.
 

Hot Threads

Recent Insights

Back
Top