Is this FRW universe matter or radiation dominant?

  • Thread starter Thread starter bon
  • Start date Start date
  • Tags Tags
    Matter Universe
Join the discussion
Registration is free. Start your own thread to ask a follow-up.
1 reply · 2K views
bon
Messages
547
Reaction score
0

Homework Statement



Metric: ds^2 = -c^2 dt^2 + (t/t*) (dx^2 + dy^2 + dz^2)

(I guess t* is a constant?)

Is this universe matter dominant? Explain

Homework Equations





The Attempt at a Solution



I guess you have to use the FRW equation?

Assuming the usual FRW form, we set a^2 = t/t*

to find H^2 depends on 1/a^4. This means it's radiation dominant, right?

Thanks
 
Physics news on Phys.org
If H^2 depends on 1/a^4 then yes, this is radiation dominant since matter is a^-3 dependent. I didn't check the work though.