Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Particle horizon in Lemaître model

  1. Dec 18, 2011 #1
    What is the exact calculation of Particle horizon in Lemaître model? Does it exist? Is it finite or infinite?
    Can anyone calculate that integral?
  2. jcsd
  3. Dec 18, 2011 #2
    The particle horizon marks the boundary between observable and un-observable parts of the universe, and yes, this integral can be calculated using the time-dependent scale factor function taken from the FLRW metric, as well as observational parameters. So far as I could find ( these things change pretty regularly ) the furthest know object to date has a redshift factor of z=8.2 which would be equivalent to a proper distance ( remember, this is not the same as light-travel distance due to the dynamic expansion of spacetime ) of about 30 billion light years. Reference :


    If you do the maths from the integral you arrive at a figure of about 46 billion light years.
    Last edited: Dec 18, 2011
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook