Light pollution is cutting humanity's connection to the stars, but we can restore it
Light pollution is cutting humanity's connection to the stars, but we can restore it
Enlarge / The galactic center of the Milky Way and Jupiter (brightest point at top center) are seen of the countryside near the small town of Rebolledo, Florida department, Uruguay in August 2020.
Mariana Suarez/Getty Images
Humans are naturally afraid of the dark. We sometimes imagine monsters under the bed and walk faster on unlit streets at night. To overcome our fears, we can leave a nightlight on to scare away monsters and a light above the porch to deter burglars.
Yet, huddled for safety under our pools of light, we lost our connection to the night sky. Star counting by the Globe at Night public awareness campaign found that between 2011 and 2022, the artificial brightness of the global night sky had more than doubled. Yet local interventions can create meaningful change.
Light pollution cuts us off from one of nature's greatest wonders, harms wildlife and blocks research that could help fight climate change. Stars are more than pretty lights in the night sky. They have shaped the mythology of all human civilizations. They guide the birds on their amazing migratory journeys. And now, we must do our part to prevent light pollution so the stars can be part of our future.
The human eye can detect about 5,000 stars in the night sky. But the light emitted by skyscrapers, streetlights and houses obscures almost all the brightest stars.
Our ancestors used the rising and setting of the constellations as calendars. They also navigated the stars as they sought new lands or charted nautical trade routes. Normally, sailors no longer use the stars to navigate, but they are still taught to do so in the event of their navigational systems failing.
Migratory animals, including birds and insects, are diverted from their natural flight paths by the “skyglow” of cities. In the summer of 2019, Las Vegas was overrun with millions of migrating grasshoppers, while the beams of New York's 9/11 Tribute in Light attract flocks of night-flying migratory songbirds.
Disoriented by the city lights, the birds crash into the skyscrapers. Insect numbers are plummeting worldwide and light pollution is making the situation worse by disrupting their nocturnal life cycle.
What is light pollution?
Light pollution is caused by the same physics that turn the sky blue during the day. Sunlight is made up of all the colors of the rainbow and each color has a different wavelength. The air around us is made up of tiny particles (such as oxygen and carbon dioxide molecules).
When sunlight passes through the air, it is scattered by these particles in random directions. Blue light (with shorter wavelengths) scatters more than red light (which has longer wavelengths). As a result, our eyes receive more blue light from all directions in the sky.
At night, the light scattered by the same air particles makes the sky shine on us. A small fraction of this skyglow is caused by natural sources, such as starlight and...
Enlarge / The galactic center of the Milky Way and Jupiter (brightest point at top center) are seen of the countryside near the small town of Rebolledo, Florida department, Uruguay in August 2020.
Mariana Suarez/Getty Images
Humans are naturally afraid of the dark. We sometimes imagine monsters under the bed and walk faster on unlit streets at night. To overcome our fears, we can leave a nightlight on to scare away monsters and a light above the porch to deter burglars.
Yet, huddled for safety under our pools of light, we lost our connection to the night sky. Star counting by the Globe at Night public awareness campaign found that between 2011 and 2022, the artificial brightness of the global night sky had more than doubled. Yet local interventions can create meaningful change.
Light pollution cuts us off from one of nature's greatest wonders, harms wildlife and blocks research that could help fight climate change. Stars are more than pretty lights in the night sky. They have shaped the mythology of all human civilizations. They guide the birds on their amazing migratory journeys. And now, we must do our part to prevent light pollution so the stars can be part of our future.
The human eye can detect about 5,000 stars in the night sky. But the light emitted by skyscrapers, streetlights and houses obscures almost all the brightest stars.
Our ancestors used the rising and setting of the constellations as calendars. They also navigated the stars as they sought new lands or charted nautical trade routes. Normally, sailors no longer use the stars to navigate, but they are still taught to do so in the event of their navigational systems failing.
Migratory animals, including birds and insects, are diverted from their natural flight paths by the “skyglow” of cities. In the summer of 2019, Las Vegas was overrun with millions of migrating grasshoppers, while the beams of New York's 9/11 Tribute in Light attract flocks of night-flying migratory songbirds.
Disoriented by the city lights, the birds crash into the skyscrapers. Insect numbers are plummeting worldwide and light pollution is making the situation worse by disrupting their nocturnal life cycle.
What is light pollution?
Light pollution is caused by the same physics that turn the sky blue during the day. Sunlight is made up of all the colors of the rainbow and each color has a different wavelength. The air around us is made up of tiny particles (such as oxygen and carbon dioxide molecules).
When sunlight passes through the air, it is scattered by these particles in random directions. Blue light (with shorter wavelengths) scatters more than red light (which has longer wavelengths). As a result, our eyes receive more blue light from all directions in the sky.
At night, the light scattered by the same air particles makes the sky shine on us. A small fraction of this skyglow is caused by natural sources, such as starlight and...
Enlarge / The galactic center of the Milky Way and Jupiter (brightest point at top center) are seen of the countryside near the small town of Rebolledo, Florida department, Uruguay in August 2020.
Mariana Suarez/Getty Images
