Are you worried about gaining some extra kilos during Christmas time? Then you may be pleased to read that your old kilograms will be gone in no time. In fact, exactly on 19th May 2019 all kilograms in the whole universe will be gone "PUFF"... and they will be replaced by brand new, much better kilograms! WOW! That is because the 26th General Conference on Weights and Measures revised the International System of Units in order to derive all SI base units from natural constants. So the kilogram is no longer defined as the mass of the International Prototype Kilogram. The new definition of the kilogram is rather: The kilogram, symbol kg, is the SI unit of mass. It is defined by taking the fixed numerical value of the Planck constant h to be 6.626 070 15 × 10 −34 when expressed in the unit J⋅s, which is equal to kg⋅m 2 ⋅s −1 , where the metre and the second are defined in terms of the speed of light and the caesium frequency . I'm sure you lost at least two kilo...