deletions | additions       diff --git a/Find_the_average_vel.tex b/Find_the_average_vel.tex  index ba1521c..b057fcb 100644  --- a/Find_the_average_vel.tex  +++ b/Find_the_average_vel.tex 
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There is no neat analytic expression for this age, but it is a relatively straightforward   calculation to do on a computer, here is a link to a program that calculate this and  other cosmological parameters made by students in the Astro group here at the University of Melbourne:  http://ph.unimelb.edu.au/cosmocalc/input.php \url{http://ph.unimelb.edu.au/cosmocalc/input.php}  . Compare the age of the universe with various other ages. The age of the  Earth is thought to be about $4.6 \times 10^9$ years. The age of the Sun