I have a question about the horizon size of the empty Milne Universe. The empty Milne Universe expands linearly with time. This implies that the horizon size for the Milne Universe is given by: d_H = Integral [ t=t_early to t_0 ] ( dt / t ) d_H = log t_0 - log t_early Thus the horizon size for the Milne Universe diverges as t_early -> 0. Does this mean that there is no "horizon problem" for the Milne Universe? It seems that the Milne model doesn't require the theory of inflation to explain the uniformity of the cosmic microwave background.