As Neils Bohr showed, it is possible for electrons to move between energy levels. Light contains energy. If a photon of light strikes an atom, it is possible for the energy in the light ray to be transferred to one of the low energy electrons moving around the atomic center.
Spotting before a period is due â reasons for spotting before a period can be implantation, from a cyst or a short luteal phase and impaired egg quality. Spotting in between cycles â this is a difficult term to answer but often means your cycles are growing shorter; often with perimenopause.
But if it coincides with an already long period, it could also be normal, but may be a sign of abnormal menstrual bleeding. According to Medscape, excessive exercise, stress, and weight loss can cause abnormal uterine bleeding or spotting, but the more common outcome of excessive exercise is an absence of menstruation.