I have a new hypothesis, field of research for you. It involves quantum
mechanics, photons, entanglement and the way eyes work, possibly alien eyes
;)
The theory/hypothesis is as follows:
1. During emission of light by a light source, for example a sun, some if
not all photons could be entangled. These entangled photons take a slightly
different path.
2. One path of photons reachs us, the other path reaches (alien) eyes.
3. Let's suppose for a moment that eyes themselfes manipulate the photons in
a predictable way, for example there rotation is altered. Then this should
trigger a change in the rotation of the other photon as well.
4. Perhaps this change is detectable, if true then (alien) eyes could be
observed in this way. For example the lens or iris changes the rotation of
photons.
5. For example by observing many photons, perhaps this could be detected.
6. Perhaps the photons need to be observed for a long time, perhaps via
mirrors, to detect this change in real time... if not possible, then it
would have to be based on rotation differences only.
Finally this also leads to a second theory:
1. Perhaps human eyes communicatie information with each other through the
iris. Perhaps the function of the human iris is to encode/decode photonical
signals through quantum entanglement.