Information

I believe that this category contains more than meets the eye. Usually information would be collecting items together so somebody can use them. If you want to write a novel situated in the middle of last century, 1957 say, you may want to have together songs and books that came out that year. How did people dress back then?, and that kind of stuff.

A spy may want to know where is Bin Laden right now. In the future one may want to know if the iPhone announced by Apple recently will take 50% of the market by 2010. The future cannot be known, but a good information gathering process may give a reliable prediction.

I believe though, that information has a deeper role in the Universe. Was there information during the Big Bang? Was there less than now? This more quantitative question requires a mathematical definition of information, Claude Shannon from Bell Labs invented such definition, and to this day is still used by communication engineers. Recently physicists have applied this measure of information for Black Hole Physics, getting interesting results.

It could be that a Universe with more information weighs more than one with less. Energy and mass were considered independent properties of matter before Einstein. After his work we can know how much energy is in one gram of Uranium if we could convert that material to energy completely. In the same way it may be possible to convert one erg of energy into some bits of information. I do not know the conversion factor, but expect that it is more than c², where c is the speed of light.