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.
launch interactive. During REM sleep (the stage of sleep most associated with dreaming) there is an increase in the firing rate of most neurons throughout the brain, as compared to non-REM sleep. In fact, the brain in REM sleep can even be more active than when we are awake. Patterns of brain activity during REM sleep are more random and variable, similar to during wakefulness. This pattern of brain activity during REM sleep probably underlies the intense dreaming that occurs during this state.