Antimatter
ANTIMATTER sounds like science fiction but it is real. Every particle has an ANTIPARTICLE — same mass, opposite charge. The electron's antiparticle is the POSITRON. Protons have antiprotons. Quarks have antiquarks. When matter meets antimatter, they ANNIHILATE — both vanish, converting all their mass into pure energy (photons). The famous E=mc² applies — total annihilation releases enormous energy per gram.
Where is it? Antimatter exists, but rarely. It is produced in cosmic ray collisions, in lightning storms, in particle accelerators, and inside our bodies (during natural radioactive decay). Hospitals use POSITRON EMISSION TOMOGRAPHY (PET scans) — radioactive tracers that emit positrons. Each positron annihilates with a nearby electron, producing photons that scanners detect. PET imaging has saved millions of lives.
One of the deepest puzzles in physics: the universe seems to contain mostly MATTER, very little ANTIMATTER. Why is this strange?
Practical antimatter. CERN's ALPHA experiment has trapped and held antihydrogen atoms for hours — long enough to study them. Comparing antimatter properties to matter could reveal subtle asymmetries. STORING significant amounts of antimatter is impossibly expensive — the highest-energy form of energy storage but currently impractical. Science fiction "antimatter engines" remain SF for now. PET scans remain the main practical antimatter use today.
PET Reality
Look up "PET scan" — millions of patients have had them. The antimatter inside is tiny but real. Each positron annihilation produces a perfectly directed pair of photons. Modern medicine uses antimatter physics every day.
Antimatter is real and weird. Why our universe has only matter is one of physics' deepest puzzles. Whatever the answer, it underlies our existence.
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