Used with
permission of Maiken Naylor, University at Buffalo, Buffalo, NY, USA,
http://ublib.buffalo.edu/libraries/units/sel/exhibits/stamps
Physicist Werner Heisenberg (1901-1976) derived the uncertainty principle named after him, which states that the product of the changes in momentum and position of a particle must be greater than Planck's constant/2 pi, meaning that both its position and momentum cannot be known simultaneously with complete accuracy. He invented a matrix mechanics that was a non-commutative algebra of probability amplitudes. For this work he received the Nobel prize in physics in 1932.