1:01:20Where Is All the Antimatter in the Universe?
An hour on the biggest bookkeeping error in physics: the Big Bang should have made matter and antimatter in equal amounts, they annihilate on contact, and yet here we are. Three Astrum films run back to back. First a thought experiment with real arithmetic in it, working out from the mass of the atmospheric column what an antimatter meteor would do to the Earth, and landing on a number that beats the Tsar Bomba by hundreds of times. Then the physics itself, from Anderson's 1932 cloud chamber and Dirac's earlier prediction through a force by force hunt for any difference between matter and antimatter, ending on ALPHA at CERN measuring antihydrogen in free fall at 0.75 g. Finally the payoff: antimatter really is raining on the Earth right now, AMS-02 has counted more than 400,000 positrons from the space station, and the source turns out to be Geminga, a dead star 800 light years away that spent fifty years pretending it was not there.