When this is over, the cycle starts over; the original star dies and becomes a white dwarf. White Dwarf The core of a white dwarf star surrounds itself with layers of hydrogen, which still burn, continuing to fuse.
REM sleep is important because it is the restorative part of our sleep cycle. Typically, you begin the sleep cycle with a period of non-REM sleep followed by a very short period of REM sleep. The period of non-REM sleep is made up of stages 1 to 4. Each stage can last from 5 to 15 minutes.
Sleep: 16-18 hours a day are spent sleeping. Half is in REM sleep and the other is Deep sleep. REM sleep is when we dream. It is when the best sleep occurs and it is truly necessary to function. Auto-Stimulation Hypothesis - REM sleep is necessary Other states consist of Drowsiness, Quiet Alertness, and Crying.