What Is Antimatter Actually Made Of and Why Did the Universe Keep Almost None?

What Is Antimatter Actually Made Of and Why Did the Universe Keep Almost None? Antimatter sounds like a prop from a science fiction film, a vial of glowing fuel or a weapon small enough to fit in a briefcase. The truth is stranger and quieter than any of that. Tonight we look at what antimatter is actually made of, particle by particle, from the positron that curved the wrong way through a cloud chamber in 1932 to the first nine atoms of antihydrogen born and gone in forty billionths of a second. We follow the single most unsettling number in physics, the one extra matter particle for every billion twins, the razor thin surplus that survived a near total annihilation and became every galaxy, every star, every planet, and you. We sit with the mystery Andrei Sakharov named in 1967, the fresh 2025 evidence that baryons themselves break the mirror, and the strange fact that a version of this same annihilation happens safely inside millions of hospital patients every year. Settle back, breathe slow, and let the leftovers of an almost perfect draw carry you toward sleep. Sources: Dirac, P. A. M. (1928). The Quantum Theory of the Electron. Proceedings of the Royal Society A. Anderson, C. D. (1933). The Positive Electron. Physical Review. Chamberlain, O., Segre, E., Wiegand, C., and Ypsilantis, T. (1955). Observation of Antiprotons. Physical Review. Christenson, J. H., Cronin, J. W., Fitch, V. L., and Turlay, R. (1964). Evidence for the Two Pion Decay of the Neutral K Meson. Physical Review Letters. Sakharov, A. D. (1967). Violation of CP Invariance, C Asymmetry, and Baryon Asymmetry of the Universe. JETP Letters. Adriani, O., et al. (PAMELA Collaboration) (2009). An Anomalous Positron Abundance in Cosmic Rays. Nature. Aguilar, M., et al. (AMS Collaboration) (2013). First Result from the Alpha Magnetic Spectrometer on the Positron Fraction in Primary Cosmic Rays. Physical Review Letters. ALPHA Collaboration (2023). Observation of the Effect of Gravity on the Motion of Antimatter. Nature. LHCb Collaboration (2025). Observation of Charge Parity Symmetry Breaking in Baryon Decays. Nature.