One of our 2015 ‘Numbers of the Year’ predictions might have come to pass. There is great excitement over rumours that one of the predictions Einstein made in his theory of General Relativity has finally been observed. But it’s not the first time it’s been reported that ‘gravitational waves’ have been discovered, and the last time proved to be an equipment test.

What is the total number of possible tweets that could be created from 140 characters? In a recent programme Professor John Allen-Paulos told us that when you take into account all of the symbols available, the total number of possible tweets is Googol^2.8 (which is a 1 followed by 280 zeros.) But has he missed some options?