antimatter

     I learned this today. Antimatter is matter made up of antiparticles. An antiparticle and a particle have the same mass but opposite electrical charges.      A proton, for example, contains three quarks (2 up and 1 down), has a positive charge, and weighs 0.00000000000167262192 picograms. (A picogram is 100 billionth of a gram.)  An […]