I learned (University Physics, 9th Edition, Extended Version) that the wave function of a particle having a definite energy is independent of time. This means the probability Density of the particle don't change with time, i.e. If a particle is 90% likely to be found some where now, There is always 90% chance of finding the particle at the same place. What I am confused on is in this Scenario--- Suppose a particle is moving in freely in free space with certain constant velocity therefore having constant Energy. Then How is it possible that the particle is always most likely to be found at its starting position.? My institution Tells me that the probability density should constantly change with time as the particle moves.