Arrived in Sainte-Décroix for the first leg of my itinerary. This city puts art above all things and literally oozes creative energy. Caffeinated and getting into flow to do some good work here. #creativespirit #ethereal #mythicalcreature #parisstyle #darkcity #artdiscover #digitalnomads https://www.instagram.com/p/CoUb6SbOWf8/?igshid=NGJjMDIxMWI=
Found yet another used entertainment place. This one even had books. These places are everywhere in Philly. Luv it!!! #TodaysFinds #SecondHand #DontBuyNew #DarkCity #KieferSutherland #Oculus #KarenGillan (at West Philadelphia) https://www.instagram.com/p/CinyU-ZP40TCmk9SVgbWtd4AJEparHN_FbGYNU0/?igshid=NGJjMDIxMWI=
Skyglow is a phenomenon caused by the artificial light used at night that causes an orange or white glow in cities at night. This makes it very difficult for people and animals to see the stars at night.
The orange/white glow comes from light sources on the ground that go up to the sky at night and scatter from dust particles or other molecules in the atmosphere. Some of that light comes back to the ground.
The map at night that shows the lights that are seen from space only shows the light that is able to get there. All other light bounces back and stays, so to speak, on the ground.
This is what most often comes to mind when the term light pollution is used. This is, however, just one symptom of light pollution.
Other ways in which we experience light pollution besides skyglow is the reflection of the light used to hit a target area. This is another contributor to skyglow. Another part of light pollution is glare, which is light that falls outside of the target area.
In addition to reflection of intentional light and of glare, light trespass is another part of light pollution, which is the light that hits apartments and buildings where that light is not wanted.
Additionally, on cloudy nights, clouds might reflect light back to the ground, increasing the brightness and adding to the skyglow. And some research also shows that snow, ice or water on the grounds from rain, adds to the brightness of the skyglow making it yet another contributor to light pollution.
So how efficient are we really using all that lightning?
To summarize it: skyglow and light pollution is caused not only by the light we use to hit the intended areas, but also by the effects of the inefficient ways in which we light. These include reflection of the intentional lighting, glare of light reaching outside of target areas, trespassing into apartments and properties, and reflection on clouds and snow or water.
Photo: Mike Knell (https://www.flickr.com/photos/mpk/171117951)
Source: IDA (International Dark-Sky Association)
Trivia: https://www.youtube.com/watch?v=TKAuWAjrj68