› Forums › General Discussion › A Christmas Photonic Teaser › Reply To: A Christmas Photonic Teaser
16 December 2022 at 11:15 am
#614688
![](https://britastro.org/wp-content/uploads/2018/09/picture-8621-1537263177-80x80.jpg)
Participant
The photons hit a receptor in the retina (not the nerve directly). They are absorbed and their energy causes a chemical reaction. A long chain of subsequent reactions eventually reach the brain.
The photoreceptor is slowly (hence a long time taken for dark-adaption) returned to its initial chemical state, with the photon’s energy ultimately converted into heat.
An explanation in terms of QED would not be illuminating!