Light Pollution: Seeing the Stars vs Seeing the City

Seeing the stars at night is exciting whatever age you are.  Stunning photos showing the vast galaxy around us are shared and favourited constantly, with many people adding comments like “I wish I could see this!” However not very long ago, those same scenes were commonplace around the globe.  So what changed?

As we moved into the modern age, lighting became a defining way to show wealth and prosperity.  Street lights became more common, as well as lighting in homes, which was amazing for the industry but not so great for the surrounding environment.  Now, many cities fight for the title of brightest city: New York is the ‘City that Never Sleeps’, Paris is the ‘City of Lights’ and Hong Kong is so lit up individual streets can be seen from space.

There are many downsides to this and they are all caused by Light Pollution.  In this post we find out what this means and why it is dangerous, as well as some prevention methods that don’t involve pulling the plug on your lighting.


The difference between the city night sky and the countryside


What is Light Pollution?

Known also as photopollution or luminous pollution, light pollution is defined as excessive, misdirected or obtrusive artificial light.  This can range from a neighbour’s outdoor lights shining into your living room, to huge cities being a constant glowing hub on the world map.

Why is it a problem?

  • Starting off small, it’s simply annoying! No one wants someone else’s lights shining into their home as it makes it difficult to relax and  it feels like an intrusion into a personal space.
  • There are adverse health effects on having too much constant light, or having the wrong lighting.  Human body clocks run on a circadian rhythm, which lasts about 24 hours and regulates when we eat and sleep. Disrupting this with constant, bright light can cause serious health issues such as insomnia and a weaker immune system.
  • Light pollution disrupts the ecosystem.  Many animals run on cycles, just like humans, and so are affected by lights in a similar way.  Also many birds and animals, like sea turtles, use lights for navigation and so can be confused by artificial city lights.
  • It obstructs the night sky through a thing called ‘skyglow’, which is caused by artificial lighting making it more difficult to see the contrast between smaller objects in the sky, meaning fewer stars are observable. This causes problems both for people wanting to see a pretty view, and for astronomers trying to observe and find out more about our universe.


What can we do to prevent this?

You don’t have to rip out all your lights and live in the dark to help reduce this type of pollution.  Here are some simple ways you can help.

  • Only using lights when it’s necessary– Obvious but true.  Remember when your parents would yell at you to turn the lights off when leaving a room?  Turns out they might have had a point, as not only does it help the electricity bill, but also the environment too.
  • Shielding your lights properly– This helps direct the light onto the task it is supposed to be illuminating while also containing the light so it does not become obtrusive.
  • Energy efficient bulbs– LEDs in particular, as they have additional dimming qualities which mean you can control the light intensity to suit your needs.  Also these can help the environment by lowering carbon emissions.
  • Thick curtains and blinds– These prevent light from escaping outside and being obtrusive to neighbours and the surrounding areas.

Many campaigns have been launched trying to reduce this harmful phenomena such as WWF’s Earth Hour.  Reducing light pollution does not have to be about getting rid of light, but by being smarter with it’s use and intensity.


Further Resources: 

Not all lighting is doom and gloom.  Read about the positives lighting can have on mood and health here:

Read more about Earth Hour here:


Abigail Houseman

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