| Solve the Friedmann equation for the case of a matter-dominated flat universe. | [3] |
|
Hence show that, in such a universe, the proper distance of an object at redshift z is
dP = (2c/H0) (1 – 1/√(1+z)), where H0 is the present value of the Hubble parameter. |
[3] |
| In a flat, matter-dominated universe with H0 = 50 km s-1 Mpc-1, a quasar is observed at redshift z = 4.0. | |
| (i) Calculate the proper distance of the quasar. | [1] |
| (ii) Calculate the time at which the light from the quasar was emitted, and hence the look-back time for the quasar. | [2] |
(2008 Q5(b).)