I am not a student. I am a retired Chemical Engineer and a retired IT Auditor (ex-ISACA member). My questions are a product of my thoughts about Physics and the Cosmos and my talks with a closer friend. Please answer me. Imagine an atom in a position P in the Universe and n observers, all them at a distance of d from it. An excited electron of the atom decays to a lower energy level and a photon is produced, whose energy is E (and is equal to the value of the difference between the electron's energetic levels before and after, isn't it?). (Remainder: a photon is an electro-magnetic wave that expands spherically from the point where the electronic transition has occurred). Question 1: How many observers will detect the photon? Question 2: What will be the measured value of the photon's energy that each observer will detect? Question 3: What will be the value of the sum of all the measured energies by the n observers? Question 4: When n goes to infinity what will be the value of the sum of the question 3? Question 5: How this last value compares with the energy E of the electronic transition?