[jamoes]

And, actually, it may continue well beyond 2140. The only reason it would stop there is because the smallest value bitcoin can currently represent is 0.00000001 BTC (1e-8). Many people believe that the rising value of bitcoin will bring about a need to increase the number of decimal places that bitcoin supports. If this change is made to the protocol before 2140, the the mining reward will probably keep on halving to values even less than 1e-8 BTC.