These are just some of the darkest days of the year - or will be when we live as our ancestors to light with nothing but the stars and the moon way between sunset and sunrise.
Instead of street lights and illuminated houses most of us live in cities and towns with lit lamps, ceiling lights, cell phones, tablets, computers and TVs. For the 15 million Americans who work the night shift, the lights stay on all night long.
The artificial brightness Everything has advantages. We can use our e-books, post on Facebook or read live at any time. But there are potential health risks if we get too much of the wrong kind of light on the wrong team.
And that's exactly what many of us do some research suggests.
"Light is a stimulus tail can affect health, wellness and performance," for better or for worse, says George Brainard, professor of neurology at Thomas Jefferson University.
Light has this power as our central biological clock increases. Ideally, the generated at night in a program of 24 hours predictable alert daytime internal clock and drowsiness. Receptors play in the eyes of a key role in their instructions from the intensity and wavelength of light intake they are exposed to each day and night.
The bright sunlight is rich in blue wavelengths that we can watch and suppress the release of melatonin, the hormone helps to sleep tail. If we especially at night, can interrupt sleep bright light, bright blue light and can even contribute to weight gain, susceptibility to cancer and other health problems, some studies suggest.
"No one is telling us not to turn off all the lights," says Mario Motta, a cardiologist in Salem, Mass., Who has with the American Medical Association (AMA) to draw attention to the effects of light during work night. But, he says, it's time to take some action to reduce the damage.
The World Health Organization also stepped in and said: "Night shift work for higher rates of breast cancer is associated. Chronic exposure during night light and suppression of melatonin, which has anti-cancer effects, could be at least partially to blame, the group says.
But the research is still "in the early days," says Brainard. He conducts a study of a LED (light emitting diode) lighting system for the International Space Station, creating bright blue light at the start of the day, working white light from the middle and more pale, more warm light before bed. If it works, the astronauts are awake and sleep productive during the day and sleep better - and the rest of us could learn a few things.
"But there is a real need for this is to try and ensure that it works as we think it works," he says.
For now, that's what Earthbound should not know about people:
The big picture-
The less light received during the day, the more prone to light interruption at night. Then attendant hermit how more can be affected by night train, would be a construction worker surfing outdoors. An office worker could take a walk outdoors during the day to get some protection.
In a report from 2016 AMA communities hit bright LED street lamps with a high degree of blue light with avoidance. He noted that warmer versions are available. Bright lights can cause dangerous reflexes, especially for older drivers and can in the illuminated counties, said the group contribute to the lack of sleep and other health problems.
Mark Rea, director of the Research Center for Lighting Industry supported by the Rensselaer Polytechnic Institute, major skeptical circadian disruptors posts are shown. "You are not looking directly at the lamp, and there is not enough time to worry," he says.
And he says there are ways to install LED lighting and adjust that brightness should not minimize.
Some research suggests the use of night computer display displays, tablet and blue light phone can disrupt sleep. In a small experiment readers were invited to use either tablets or paper books at night. Redbourn tablet users to sleep more and were less rested the next day.
But each of these effects depend on "how far is it from the eyes, the brighter it is, the amount of blue light emitted" condition, and the amount of light during the day, says Charmane Eastman, University Medical Center.
It makes sense to device or two hours before you throw it out, says Mariana Figueiro, Professor Rensselaer Lighting Center. "If you can not turn it off, dim it and reduce the color if you can," she says. You can download the blue light on an iPhone or iPad by selecting the "Night Shift" option.
While laboratory studies show virtually any amount of light at night can suppress melatonin, "night light levels in homes are extremely severe" and is likely to cause major problems, Rea says.
However, all lights are sold for home use - whether incandescent, fluorescent or LED - are for brightness (lumens) and color (nominal score of kelvin, at 2,500 to a blue 6500 amber normal hot from cold up). And some LED lighting systems allow users to adjust color and brightness. Thus, owners who want warmer, can dim light at night.