Why the Proton 'Lost Weight' and Then 'Gained It Back' ⚡ экспресс
Original: "The Proton Radius Puzzle"
Muonic hydrogen revealed the proton's size to be 4% smaller than earlier, putting the laws of physics into question.
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It seemed that the electron's heavy 'brother'—the muon—saw the proton 4% smaller. This threatened to upend physics: Coulomb's law was in doubt. But it turned out the old rulers were lying. Crisis averted without new physics.
🎯 The muon decays in 2 microseconds. Light travels only 600 meters in that time. Yet it's enough for muonic hydrogen to yield the most precise proton size measurement in history.