principle to be compatible with the scientific method, another explanation for the flatness problem was needed. Inflation The standard solution to the flatness problem invokes cosmic inflation, a process whereby the universe expands exponentially quickly (i.e. grows as with time , for some constant ) during a short period in its early history. The theory of inflation was first proposed in 1979, and published in 1981, by Alan Guth. His two main motivations for doing so were the flatness problem and the horizon problem, another fine-tuning problem of physical cosmology. However, “In December, 1980 when Guth was developing his inflation model, he was not trying to solve either the flatness or horizon problems. Indeed at that time, he knew nothing of the horizon problem and had never quantitatively calculated the flatness problem”. He was a particle physicist trying to solve the magnetic monopole problem. The proposed cause of inflation is a field which permeates space and drives the expansion. The field contains a certain energy density, but unlike the density of the matter or radiation present in the late universe, which decrease over time, the density of the inflationary field remains roughly constant as space expands. Therefore, the term increases extremely rapidly as the scale factor grows exponentially. Recalling the Friedmann Equation , and the fact that the right-hand side of this expression is constant, the term must therefore decrease with time. Thus if initially takes any arbitrary value, a period of inflation can force it down towards 0 and leave it extremely small - around as required above, for example. Subsequent evolution of the universe will cause the value to grow, bringing it to the currently observed value of around 0.01. Thus the sensitive dependence on the initial value of Ω has been removed: a large and therefore 'unsurprising' starting value need not become amplified and lead to a very curved universe with no opportunity to form galaxies and other structures. This success in solving the flatness problem is considered one of the major motivations for inflationary theory. Post inflation Although inflationary theory is regarded as having had much success, and the evidence for it is compelling, it is not universally accepted: cosmologists recognize that there are still gaps in the theory and are open to the possibility that future observations will disprove it. In particular, in the absence of any firm evidence for what the field driving inflation