| In the context of the standard (pre-inflation) Big Bang model, explain what is meant by the following catch-phrases, and why they are described as "problems": | |
| (i) the horizon problem; | [2] |
| (ii) the flatness problem; | [2] |
| (iii) the monopole problem. | [2] |
| Briefly explain the term "inflation", and explain why introducing a period of inflation solves the above problems. | [2] |
| Inflation is generally modelled as a large positive cosmological constant. Show that in this model the expansion factor of the universe during inflation is given by a(t) = a(ti) exp[H(t – ti)], where ti is the time that inflation starts. If we assume that inflation starts at 10-35 s, ends at 10-33 s, and involves 100 e-foldings of expansion, what is the implied value of the cosmological constant Λ? | [3] |
(2005 Resit Q5(a) and (c).)