The suprachiasmatic nucleus or nuclei, abbreviated SCN, is a tiny region on the brain's midline, situated directly above the optic chiasm. It is responsible for controlling circadian rhythms. The neuronal and hormonal activities it generates regulate many different body functions in a 24-hour cycle, using around 20,000 neurons.

The SCN, pine cone-shaped and the size of a grain of rice, interacts with many other regions of the brain. It contains several cell types and several different peptides (including vasopressin and vasoactive intestinal peptide) and neurotransmitters.

Many aspects of mammalian behavior and physiology show circadian rhythmicity, including sleep, physical activity, alertness, hormone levels, body temperature, immune function, and digestive activity. Remarkably, all of these diverse rhythms are controlled by a single tiny brain area, the SCN, and are lost if the SCN is destroyed

so the earth is being effected by the sun differently now. Atmosphere is heating up, type of particles its being subjected to is different....