The Doppler effect is a mysterious wavelength-shifting phenomenon which seems to primarily affect sirens, which is why the 🚨 emoji is red.
This comic has triggered me. We do not know why the doppler effect is a thing for light(that I am aware). Is it a wave, is it a particle, both? Only when you observe it? Photons are weird.
My understanding: light can best be described as an excitation of the electromagnetic field of spacetime. This excitation has a frequency, like an oscillation. Therefore light appears like a wave and we observe the Doppler effect. However, when interacting with other excitations, the “wave” collapses and behaves like a point like particle.
This applies not only to light, but to all known particles, e.g. the protons in your body. The only difference to photons are additional spacetime fields that are involved (like the Higgs field).
The weirdest part to me, is the collapse of the imaginary wave function and how it leads to ideas like “Many Worlds”.
I always thought the observation collapse of the wave function thing was a little handwavey. I really don’t have a resolution for it though, or an alternative.