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.
If the woman has a condition and does not produce much estrogen then spotting would be a period. People on continuous cycling of oral contraceptive who go off can have light to spotting for a period. The use of Progesterone can inhibit the growth of the uterine lining so all you might get is spotting.