Antimatter
Subatomic material composed of antiparticles that share identical mass, spin, and lifetime as normal matter particles but possess opposite electric and quantum charges.
Governing formula
e⁺ + e⁻ → 2 γ (511 keV gamma photons)
SI unit
Energy (MeV / GeV)
In depth
Predicted by Paul Dirac's relativistic wave equation in 1928. When a matter particle encounters its corresponding antiparticle, they undergo mutual annihilation, converting 100% of their rest mass into pure high-energy gamma-ray photons.
Examples in the real world
Positrons (anti-electrons) emitted during PET medical imaging scans, annihilating with body electrons to produce diagnostic 511 keV gamma rays.