I'm really confused about the de Broglie wavelength thing. Like I understand that according to the formula large objects have wavelengths that could not be observable in the real world but i still don't understand what type of wave de Broglie is referring to. Is he referring to longitudinal waves or something? Would that mean that a baseball bobs up and down or side to side or back and forth when it moves? If so what causes that motion in objects? If it's not longitudinal, what type of wave is he talking about?