Biological clocks: how does our body know that time goes by?

[UM-Bot]

If you spent months cut off from the outside world, would you be able to tell if it was even day or night ?

https://www.unexplained-mysteries.com/news/369972/biological-clocks-how-does-our-body-know-that-time-goes-by

[quiXilver]

Light exposure and the circadian rhythm is an extremely deep reciprocative process with psyche and environment. 

Most any urban or suburban setting is almost entirely devoid of pitch black, ever. 

I recall the time, some dozen years ago now where in the midst of prolonged bouts of stillness an insistent message kept arising in my awareness.  A deep longing, a craving for an absence of light, for complete, pitch dark.  Eventually it was as if my very skin were pleading to me repeatedly and ceaselessly ''enough with the incessant light!  let us rest in and drink of darkness for a time''.   Over time I've come to heed and lean into such intuitive promptings from within.

Lacking an appropriate cave environment, I built myself a small but comfortable, truly lightless box in which to sit in pitch dark for as long as suited me.   The effects were profound beyond my imaginings.  It was particularly amazing to sit in truly lightlessness with eyes open.  Paradigm shifting stuff.

And from impact of those forays I realized that from then on, whenever possible, the room in which I slept would have true black out curtains and no ambient light of any kind at night.