One of the negative effects of industrialization on human activity and the environment is the production of excessive light. It may seem strange, but excess light is a form of pollution, particularly at night. The negative effects of light pollution impact many fields of study, including economics, ecology and, of course, astronomy.

Most people do not consider the surplus of artificial light as a form of pollution because it is not permanent; all we must do is collectively turn out our lights to make it disappear. In reality, however, such a solution is unrealistic because our society needs artificial light to function.

Sky over Sherbrooke cityLight pollution is mainly caused by lighting systems that are misdirected, excessive, inefficient or unnecessary. Most light pollution is found in urban settings where artificial light sources are numerous. In these areas, light sources may be partly directed towards the sky, or downward directed light may be reflected upward. Light is then dispersed by layers in the atmosphere and produces a glow that diminishes the darkness of the night sky. In large Canadian cities, more than 95% of stars that can normally be seen wi Read More
One of the negative effects of industrialization on human activity and the environment is the production of excessive light. It may seem strange, but excess light is a form of pollution, particularly at night. The negative effects of light pollution impact many fields of study, including economics, ecology and, of course, astronomy.

Most people do not consider the surplus of artificial light as a form of pollution because it is not permanent; all we must do is collectively turn out our lights to make it disappear. In reality, however, such a solution is unrealistic because our society needs artificial light to function.

Sky over Sherbrooke cityLight pollution is mainly caused by lighting systems that are misdirected, excessive, inefficient or unnecessary. Most light pollution is found in urban settings where artificial light sources are numerous. In these areas, light sources may be partly directed towards the sky, or downward directed light may be reflected upward. Light is then dispersed by layers in the atmosphere and produces a glow that diminishes the darkness of the night sky. In large Canadian cities, more than 95% of stars that can normally be seen with the naked eye are no longer visible

© 2006 An original idea and a realization of the ASTROLab of Mont-Mégantic National Park

Colour composite photo of the Earth at night taken from space

Composite satellite photograph of the Earth at night showing light projected into space.

NASA/NOAA

© NASA/NOAA


Colour photo of Sherbrooke at night showing the glow of the lights in the sky

Glow above the city of Sherbrooke located 100 kilometres from the Mont-Mégantic Observatory.

ASTROLab of Mont-Mégantic National Park

© 2006 An original idea and a realization of the ASTROLab of Mont-Mégantic National Park


The negative effects of light pollution on human activity are numerous. From an economic point of view, for example, the use of excessive lighting or unnecessary lighting constitutes a waste of energy that is costly to both the individual and to industries. In Quebec, the cost of “lighting the sky” is estimated at 45 million dollars per year. On a larger scale, excessive lighting can have an impact on global climate change if the required electricity was generated by burning fossil fuels.

Wildlife and plants are also affected. For example, nighttime lighting can confuse animals that migrate (like moths and migratory birds), can modify predator-prey relationships, and can even alter competitiveness within the same species.

In the case of moths, for example, it was discovered that numerous flowering plants declined in numbers when the flight paths of pollinating moth species were affected by light pollution.
Excessive algae growth

It is even possible for entire ecosystems to be affected. In lakes, for example, zooplankton may stop feeding on algae if nighttime lighting is too strong. The result is excessive algae growth that eventual Read More
The negative effects of light pollution on human activity are numerous. From an economic point of view, for example, the use of excessive lighting or unnecessary lighting constitutes a waste of energy that is costly to both the individual and to industries. In Quebec, the cost of “lighting the sky” is estimated at 45 million dollars per year. On a larger scale, excessive lighting can have an impact on global climate change if the required electricity was generated by burning fossil fuels.

Wildlife and plants are also affected. For example, nighttime lighting can confuse animals that migrate (like moths and migratory birds), can modify predator-prey relationships, and can even alter competitiveness within the same species.

In the case of moths, for example, it was discovered that numerous flowering plants declined in numbers when the flight paths of pollinating moth species were affected by light pollution.
Excessive algae growth

It is even possible for entire ecosystems to be affected. In lakes, for example, zooplankton may stop feeding on algae if nighttime lighting is too strong. The result is excessive algae growth that eventually decomposes and causes an increase in bacterial activity. This leads to oxygen depletion in the lake, and many species of invertebrates and fish then die by asphyxiation.

In astronomy, light pollution is a real and pressing problem. It diminishes the contrast between the dark sky and celestial sources of light, which makes it harder to see the stars. For the amateur astronomer, it is a major problem because access to a truly dark sky is increasingly difficult to find.

The increasing inaccessibility of the starry sky is unfortunate because it has become evident that amateur astronomy plays an important role in the development of scientific interest among young people. In 2003, the British government even acknowledged the link between a reduced interest in the sciences and an increase in light pollution!

For professional astronomers, artificial light is undesirable because it interferes with the collection of data. This is why new observatories are built in isolated regions.

© 2006 An original idea and a realization of the ASTROLab of Mont-Mégantic National Park

Colour photo taken from the air of an Algal Bloom

Algal bloom.

NOAA

© NOAA


Programs to reduce light pollution have been started up by several astronomical centres across Canada, including ASTROLab and the Mont-Mégantic Observatory, the David Dunlap Observatory in Toronto. A number of amateur astronomy associations are also involved in protecting our endangered legacy, the starry night sky.

The focus of light pollution abatement programs is to change the habits of the general population, companies and urban planners so that less artificial light will be wasted or misdirected. The plans typically revolve around three lines of action.

The first consists of using lighting equipment that properly directs light where it is required, and not to the sides or towards the sky. The second is to use efficient lighting sources that produce less light pollution. Low or high pressure sodium vapour lamps are recommended. The third is to use an appropriate level of lighting and to only light when necessary.

Your turn to get involved!

Follow this link to a light pollution activity.
Programs to reduce light pollution have been started up by several astronomical centres across Canada, including ASTROLab and the Mont-Mégantic Observatory, the David Dunlap Observatory in Toronto. A number of amateur astronomy associations are also involved in protecting our endangered legacy, the starry night sky.

The focus of light pollution abatement programs is to change the habits of the general population, companies and urban planners so that less artificial light will be wasted or misdirected. The plans typically revolve around three lines of action.

The first consists of using lighting equipment that properly directs light where it is required, and not to the sides or towards the sky. The second is to use efficient lighting sources that produce less light pollution. Low or high pressure sodium vapour lamps are recommended. The third is to use an appropriate level of lighting and to only light when necessary.

Your turn to get involved!

Follow this link to a light pollution activity.

© 2006 An original idea and a realization of the ASTROLab of Mont-Mégantic National Park

Colour photo of a low pressure Sodium Lamp

Low pressure sodium lamp.

ASTROLab of Mont-Mégantic National Park

© Public Domain


Colour video of Hubert Reeves in front of images of space

Hubert Reeves talks about light pollution.

Light pollution. It’s a fact that year by year, the amount of light emitted by cities around the world – urban lighting – has become excessive. The first effect, and I would say the most dramatic, is that it steals the sky. People no longer see the sky. There are many people out there who have never seen the Milky Way, who have never seen zodiacal light. Sometimes I ask people, “Do you know what zodiacal light is?” Three-quarters of them do not know, they have never even heard the word. It’s part of something that held great significance in the past. It’s contact with the sky. It’s that feeling you get when you go outside on a beautiful starry night, Milky Way and all. That contact was present throughout humanity until only a few decades ago. It is absent now and it must be given back to the people, but this can only happen by continuing the growing battle against light pollution, by explaining why it is not necessary for so much lighting, that it is useless to light up the sky, that it is a waste of energy. Nowadays everyone is looking to reduce energy, yet we still light up the sky. What a complete waste! Another important consideration, that we are only just now realizing, is that light pollution also causes significant disturbances to plant and animal life.

ASTROLab of Mont-Mégantic National Park

© 2006 An original idea and a realization of the ASTROLab of Mont-Mégantic National Park


Learning Objectives

The learner will:
  • identify recent contributions, including Canada’s, to the development of space exploration technologies;
  • describe in detail the function of Canadian technologies involved in exploration of space;
  • draw a solar system with all its components;
  • establish the link between atoms and light using different instruments.

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