another hypothesis is that spin-coupled electrons preferentially and directionally emit photons from a cryptochrome protein.  But tbh, we don&#x27;t really know yet.<p><a href="http:&#x2F;&#x2F;www.ks.uiuc.edu&#x2F;Research&#x2F;cryptochrome&#x2F;" rel="nofollow">http:&#x2F;&#x2F;www.ks.uiuc.edu&#x2F;Research&#x2F;cryptochrome&#x2F;</a>