Saturday, November 26, 2016

The Light Pollution Factor

Light pollution is a major issue when trying to observe the night sky.  Street lights, cars and exterior home lighting all contributes to light pollution in the city.  What this means for backyard astronomers is a washed out sky with very few observable stars.

Light pollution is also bad for your health, it affects more than just astronomy.


The dissappearance of the Milky Way


Less than 100 years ago, everyone on Earth could look up at the night sky and see a stunning sight of the Milky Way.  With today's light pollution, children across the globe will never experience the night sky in this way where they live.  The widespread use of artificial light not only affects our view of the night sky, but also our environment and our health.


Light Pollution's affect on Human Health 


What is light pollution?


Also known as luminous pollution, light pollution is the excessive artificial light created by humans on Earth.  This light is misdirected and obtrusive in nature because it serves no useful purpose.  Artificial lighting should be concentrated towards the ground and not up into space.  It is the alteration of natural light levels in the outdoor environment.

Telescope with light pollution surrounding it

Light pollution is a major side effect of urbanization, and is linked to several negative health issues including insomnia. Not only that, but it affects the lives of animals on Earth as well.  This sprawling epidemic of light disrupts ecosystems.

Light pollution spoils aesthetic environments.  According to the World Atlas of Artifical Night Sky Brightness, 80% of the world population lives under skyglow. 


What this means for Astronomy


For observers in the city, light pollution competes with starlight in the night sky.  It interferes with astronomical observatories that were built before such levels of light pollution existed.  The David Dunlap observatory in Richmond Hill, Ontario is an example of an observatory surrounded in light pollution.


David Dunlap Observatory in Richmond Hill


The excessive light produced by growing cities intrudes on areas that would otherwise have a natural low-light setting.  The intense glow from major cities like Toronto, Ontario can be seen for 100 miles in every direction. 


Toronto Light Pollution Map 

What contributes to Light Pollution?


  • Building exterior lighting
  • Interior Lighting
  • Advertising
  • Commercial Properties
  • Offices
  • Factories
  • Streetlights

Light pollution is the most severe in highly industrialized areas.  Densely populated cities such as Toronto are the worst offenders. Luckily, a global dark-sky movement has emerged, with concerned individuals campaigning to reduce light pollution worldwide.

Do your part to reduce light pollution by avoided uncessary artifical lighting at your home or business.  Together we can move towards a future with less wasted energy and reclaim our connection with the night sky above.




International Dark Sky Association

Light Pollution Atlas

Light Pollution Map