Science Forums: Calculating age of the universe using redshift? - Science Forums

Jump to content

Welcome to ScienceForums.Net!

Welcome to ScienceForums.Net! We welcome science discussion at all levels — from beginners to researchers, covering topics from biology to computer science, and much more. Registration is fast and free, and allows you to post on the forums, so register now and join the discussions!

After you've registered, come in and introduce yourself, or visit the forum index. If you need any help registering, posting, or if you just have some questions about our site, please feel free to contact us at staff at scienceforums dot net.

  • Start new topics and reply to others
  • Subscribe to topics and forums to get automatic updates
  • Create a ScienceForums.Net Blog!
Guest Message © 2010 DevFuse
Page 1 of 1
  • You cannot start a new topic
  • You cannot reply to this topic

Calculating age of the universe using redshift? Rate Topic: -----

#1 Posted 16 March 2010 - 12:01 AM User is offline   zeion  (Lepton)


Hello. This is one of my coursework questions I was wondering if I could get some insight here.. here is the question:

The size of the Universe if conveniently parameterized by a scale factor, a(t), which simply describes how big the Universe is at other times relative to its present size (ie. at the present we say that a is 1, and at some time in the past when the Universe was half as big as it was today, then a was 0.5). A matter-dominated Universe grows with time as a \propto t^{\frac{2}{3}} . Assuming the Universe is 13.5 billion years old at present, how old is the Universe at redshifts, z, of z = 0.5 ... etc, z= 100? Assume that we presently live in a matter-dominated Universe, and that the Universe is matter-dominated out to redshifts of at least 100.


The formula for redshift relative to scale factor is 1 + z = \frac{a_{now}}{a_{then}} Then, since a \propto t^{\frac{2}{3}} then 1 + z = t^{\frac{2}{3}}
Then I plug in z and solve for t, then divide the current age by t?
0

Share this topic:


Page 1 of 1
  • You cannot start a new topic
  • You cannot reply to this topic

1 User(s) are reading this topic
0 members, 1 guests, 0 anonymous users