It is often said that human eyes are a quasi-perfect machine, the masterpiece of evolution, but it was not known exactly how far their ability to capture visual stimuli went. Well, as revealed by research published in the journal Nature Communications , they are even better tuned than previously thought: they even perceive individual photons, the indivisible particles of light .
” That cannot be defined as ‘seeing’, it is almost a feeling, on the threshold of imagination” , has described, astonished, Alipasha Varizi, the physicist from Rockefeller University in New York who has not only directed the study, but you have experienced the “monophotonic” sensation in the first person.
After keeping three volunteers in a darkened room for 40 minutes, Varizi and his team began pressing a button that made them hear two sounds separated by one second. Sometimes one of those sounds was accompanied by the emission of a photon . Although these elementary particles do not always reach the most photosensitive cells of our eye, the rods –there are also cones, more specialized in capturing color–, the study participants answered that they registered the photons with a certainty and statistical frequency that further away the result of mere chance .
Before, it had already been verified that the rods of vertebrates – specifically, of frogs – were activated when a single particle struck them, but it remained to be ascertained whether the signal traveled to the brain or was filtered by the retina when considering it “noise” . According to experts, this work may also inaugurate a new field of research: one that leads to knowing how the quantum properties of photons affect biology, such as the possibility that they are in two places at the same time.
