http://www.bbc.co.uk/news/magazine-16964783

Stages of sleep

Every 60-100 minutes we go through a cycle of four stages of sleep

Stage 1 is a drowsy, relaxed state between being awake and sleeping – breathing slows, muscles relax, heart rate drops

Stage 2 is slightly deeper sleep – you may feel awake and this means that, on many nights, you may be asleep and not know it

Stage 3 and Stage 4, or Deep Sleep – it is very hard to wake up from Deep Sleep because this is when there is the lowest amount of activity in your body

After Deep Sleep, we go back to Stage 2 for a few minutes, and then enter Dream Sleep – also called REM (rapid eye movement) sleep – which, as its name suggests, is when you dream

In a full sleep cycle, a person goes through all the stages of sleep from one to four, then back down through stages three and two, before entering dream sleep Source: Gregg Jacobs

http://io9.gizmodo.com/5981472/what-is-the-purpose-of-the-universe-here-is-one-possible-answer

Well, it just so happens that there is a theory that gives a kind of raison d’etre to our universe and all the objects flying through it. If true, it would mean that our universe is nothing more than a black hole generator, or a means to produce as many baby universes as possible. To learn more, we spoke to the man who came up with the idea.

It’s called the theory of Cosmological Natural Selection and it was conjured by Lee Smolin a researcher at the Perimeter Institute for Theoretical Physics and and an adjunct professor of physics at the University of Waterloo. Smolin proposed that Darwinian processes still apply at the extreme macro-scale and to non-biological entities. Because the universe is a potentially replicative unit, he suggests that it’s subject to selectional pressures. Consequently, nearly everything the universe does is geared toward replication.

http://www.inc.com/geoffrey-james/how-steve-jobs-trained-his-own-brain.html