Yeah, it's weird to me that an atomic transition can create something with a wavelength so much longer than the atomic radius.
(Yeah, I know that it's a really low-energy transition, and I know about the relationship between energy and wavelength. But the net result I still find highly counter-intuitive.)
What helps me is thinking of it in term of period instead given that the wavelength is the spatial propagation of a change in field. It’s big, but that’s because C is high.
(Yeah, I know that it's a really low-energy transition, and I know about the relationship between energy and wavelength. But the net result I still find highly counter-intuitive.)