The atomic orbital refers to the physical region where the electron can be calculated to be present, as defined by the particular mathematical form of the orbital (the statement is extracted from atomic orbitals-wiki). The picture of 1s orbital seems to signify that electron can exist in the same place as the protons. Is this the case? When the distance between proton and electron becomes 0, the gravitational force becomes ∞(considering limits). So, for the electron to escape from the proton, electron needs to have high velocity nearly ∞, which means temperature to be ∞. I don't think we have ever observed such a situation where we have a chunk of matter with ∞ temperature. This condition doesn't seem to allow electron to stand in place of proton, but the QM (if I am not wrong) says it is possible. What do you say, is it possible for the ghostly electron to stand in the same place as the proton?