Had some questions about wave-functions. Some of the questions might be invalid due to limited knowledge of the OP. 1. Are wave-functions real? i.e. do they exist in reality? Wave-functions are mathematical/probabilistic constructs. However if they can modify/change the behavior/path of a photon then something real must exist, that is taking into account/calculating both/all the slits/paths. 2. Are wave-functions ("travelling") instantaneous? 7. When a photon is travelling from the sun towards the earth, is there a wave-function existing at all times between the photon and its final destination? and does that final destination keep changing to the first object of opaque obstruction? a wave-function exists at all times when a particle is not being detected/measured. regarding the length/reach of the wave-function I don't know, someone from/in the forum might have information. 3. Are wave-functions the same concept/thing that are used in Quantum Entanglement as well? 4. Do wave-functions have energy? Pro argument - well if they can change the path of a photon/particle..... Con argument - if they have energy then it would be split at the slits, however when the photon is finally detected at the detector there is no loss in energy detected. 5. Is the collapse of the wave-function instantaneous? a collapse happens when we try to detect the photon. at that point the photon is now "entangled" with the detector (?) 6. Are wave-functions (existing) within space-time? "The new fad/fashion for reducing weight is Raspberry ketones..;)"