John Healy (draft 6-18-2024, 7-22-2024) For an update on this question, see my October 2025 post “AIsaysWhat.physics – the take of scrape – photon chat.” 1 Introduction What might be expected if you asked, à la a Jay Leno “Jaywalking” segment [1], some random people this question: “How big is a photon?“ Well, aside from … Continue reading How big is a photon?