For how long must light be emitted for a human eye to perceive it?

  • Would a person notice a flash of light that lasted 10 ms?
  • Does the intensity of the light matter?
  • How much light is a photon, anyway? Does is take thousands or trillions of photons interacting with the eye to register as light?

1am where I live and I'm wondering

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[–] 34 points 2 months ago (1 child)

A 2016 Nature study found the human eye can detect a single photon just above chance, while conscious sight needs about 5 to 9 photons.

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