Hospital PET scanners run on antimatter every day: a radiotracer emits positrons, each positron meets an electron in tissue and annihilates into two 511 keV photons flying back to back, and the detector ring simply reconstructs the line between them. The reverse is just as real: a gamma photon carrying at least 1.022 MeV, passing near a nucleus, can turn into an electron–positron pair. Carl Anderson caught the first positron in cosmic rays in 1932; why the universe is left made entirely of matter, nobody knows for sure.
Hospital PET scanners run on antimatter every day: a radiotracer emits positrons, each positron meets an electron in tissue and annihilates into two 511 keV photons flying back to back, and the detector ring simply reconstructs the line between them. The reverse is just as real: a gamma photon carrying at least 1.022 MeV, passing near a nucleus, can turn into an electron–positron pair. Carl Anderson caught the first positron in cosmic rays in 1932; why the universe is left made entirely of matter, nobody knows for sure.
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