Sleeping in the dark question
Is the problem with light in the bedroom the effect of it on your skin or what gets to your eyes through your eyelids?
I think it could disturb your sleep cycles, probably by waking you fully when you stir in your light sleep. So eyes, I'm tipping. Wear an eye mask? Works wonders for me.
Yes, definitely eyes. next chance you get, look closely at someone's eyes while they're closed. Many people's eyes don't exactly "seal" shut, you can see the whites, so moving about may cause light to filter in and cause restless sleep. I am one of those people and have to put a sheet over the lights on my air conditioner because, to me, they light up the room.
Well, according to Lights Out, there was an experiment in which they shone a small light source behind a subject's knee and that was enough to depress his release of melatonin really significantly.
Originally Posted by Finnabair
So it seems it's not just your eyes.
I did hear one of the authors of that book speaking on the radio more recently, however, and she said that women function best when they get the appropriate dose of moonlight as the moon waxes and wanes. (But that's irrelevant to men.) I don't know what proof she has of that, but I'd not be surprised.
I guess closest to nature, and probably best, would be a bedroom in which all artificial lights (including clock and radio dials, etc.) are doused and into which streetlamps (and other forms of light pollution) don't leak but which the moon can get into. (The moon is, obviously, a far less intense light-source (being farther away) and is also cyclic, not at the same fixed intensity every night.)
In practice, that can only happen these days in right out in the country. If you're in town the best solution is probably to make your bedroom just as light-proof as you possibly can. If that means having shutters made, or taking Heath Robinson-like manoeuvres such as clipping the end of the curtain to the windowsill and draping towels over the top bit where the light comes through, it might be worth it. Most people who take at least some steps towards darkening their sleeping room report longer and much-improved sleep.
It's definitely not just your eyes. All of your skin has photosensitive pigments that react to light levels and help regulate circadian rhythms. Eyes are probably the most important, but the other ones can matter too.
On the other side of the coin, if your room is still dark even after the sun comes up because you have blackout curtains, how does that not cause the opposite problem, of not being woken up naturally?
I am in the early stages of inventing an automatic system that is programmed to sync to internet time, can calculate sunrise/sunset time for my house's coordinates, and will open/close the curtains accordingly (and silently, so I am not awakened by the sound of the curtains moving instead of the sunlight), but that will take me a while to finish since I have other projects and a job to take up my time. And it needs to be pretty cheap if I want to apply it to all of the windows in the house eventually.
How did Grok sleep? Did he sleep in caves or holes? They had moonlight back then.
Also, slight side note - don't turn on lights if you get up to use the restroom, etc, in the middle of the night. Sudden strong lights affect your skin severely because - like your eyes - your skin is used to the darkness. Source: I read something about blah-blah-cancer-risk-blah-blah somewhere a while ago.
Yes, but the moon does wax and wane—it's not constant as streetlights are.
Caves? People sometimes used the front parts of caves or camped under overhanging rocks—rock shelters might be a better term than caves. They probably didn't often go deep into caves unless they had a special reason for doing so—such as painting rock art, which they often chose to do in near inaccessible places. These were perhaps intentionally womb-like, or perhaps just deep enough to be somewhere specially set-aside, or perhaps somewhere somewhat disorientating (through sense-deprivation).
In any event, it would be wrong to think of people living in a cave permanently in the way modern humans might live in a house. For a start, they might need to follow migrating game animals. You have to think of hunter-gatherers as being at least sometimes on the move—or at any rate as moving between favoured camping-sites on a seasonal basis, here for the shellfish, there for the fruit when it ripens, and so on.
People likely often used temporary shelters as hunter-gatherers in recent times do. Compare an Apache wikiup:
wikiup - Google Search
Such dwellings wouldn't be light-tight, and besides people might have kept fires going—for warmth or to scare off animals, and so on. However, it would have been very much darker than it is in town these days. I can recall spilling out of the pub at closing time when living in the country and having trouble seeing where I was going. Your eyes adapt gradually, although it takes about 30 to 40 minutes, but it's so much darker than in town. Where there are no streetlights the difference is striking.
I understand that there are a few astronomical observatories that are no longer of much use, because they're too near towns. Now that's light-pollution. These days they tend to site them well away from built-up areas.
One has to bear in mind that artificial lighting is so bright and so round-the-clock that it can actually be seen from space. This was a point made by U.S. Defense Secretary Donald Rumsfeld in 2002. He pointed out that South Korea's lights (and pretty much everyone else's) can be seen from space, but that North Korea is dark because, despite it's having the bomb, they're living in poverty, and showed a striking image.
North Korea is Dark
At least people in North Korea even if they have to live under the heel of a mad dictator probably get a good night's sleep!
Definitely the case; in fact that's why Flagstaff, AZ has strict light-pollution ordinances, to avoid destroying the view of space from the nearby Lowell Observatory.
Originally Posted by Lewis
Fun fact: Pluto was discovered at Lowell Observatory. Slightly less fun since Pluto has been downgraded from planetary status, but there you go.
Thanks for confirming that.
It brings home that nowadays our nights aren't as dark as they should be really nicely.