Scientists Say: Light pollution | Science News for Students

Scientists Say: Light pollution

This is when artificial light leaks into places that are normally dark
Jun 10, 2019 — 6:45 am EST
a photo of the earth at night from orbit showing how bright populated areas are

People produce so much extra light that our light pollution can be seen from space.

Craig Mayhew and Robert Simmon/NASA GSFC

Light pollution (noun, “LIE-T Poll-OO-shun”)

This is when light from non-natural sources shines in places that are naturally dark. This artificial light is any kind of light made by people. Streetlights illuminating an area at night produce light pollution. So do the lights from buildings, cars and even campfires.

Lights at night can provide safety for people — think of how difficult or dangerous it would be to walk down a city street or through a parking lot in the dark. But this light is not so great for other organisms. It can mess with the circadian rhythms of plants and animals. And biological functions that occur in 24-hour cycles, such as when insects come out and pollinate night-blooming plants and when plants grow or bloom, can also be disrupted by this light. It can also lead migrating birds astray and force seabirds to land, exposing them to predators.

Light pollution can make it especially hard for people in cities and towns to see stars and planets. That’s why it’s often easier to stargaze in the country than in the city. 

In a sentence

People are so sensitive to light pollution that even a full moon will disrupt our shut-eye.

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Power Words

(more about Power Words)

circadian rhythm     Biological functions such as body temperature and sleeping/waking times that operate on a roughly 24-hour cycle.

disrupt     (n. disruption) To break apart something; interrupt the normal operation of something; or to throw the normal organization (or order) of something into disorder.

light pollution     The intrusion of unwanted light into areas that would naturally remain dark. Light pollution interferes with our ability to view the night sky. It also alters the circadian rhythms of plants, animals and people.

moon     The natural satellite of any planet.

organism     Any living thing, from elephants and plants to bacteria and other types of single-celled life.

planet     A celestial object that orbits a star, is big enough for gravity to have squashed it into a roundish ball and has cleared other objects out of the way in its orbital neighborhood. To accomplish the third feat, the object must be big enough to have pulled neighboring objects into the planet itself or to have slung them around the planet and off into outer space. Astronomers of the International Astronomical Union (IAU) created this three-part scientific definition of a planet in August 2006 to determine Pluto’s status. Based on that definition, IAU ruled that Pluto did not qualify. The solar system now includes eight planets: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune.

star     The basic building block from which galaxies are made. Stars develop when gravity compacts clouds of gas. When they become dense enough to sustain nuclear-fusion reactions, stars will emit light and sometimes other forms of electromagnetic radiation. The sun is our closest star.