Knowledge.

Knowledge cubes yesterday.

Knowledge is not only measurable but has in fact been measured, in 1976 in fact by Dr Quang Johnstone. Knowledge was found to form cubes of no more than 8 centimetres square, and that there were exactly 1.7 trillion liquid hectares of these cubes in existance.

Of course since 1976 these cubes have multiplied to reach a staggering 4.3 trillion liquid hectares. It has also been calculated that knowledge cube growth averages around 10,000 per day.