ENVIRONMENT

A new sky atlas reveals the worsening state of light pollution. (Nat Geo News)

Use our resources to learn a little about light pollution.

Teachers, scroll down for a quick list of resources in our Teachers Toolkit, including a citizen science project perfect for those summer nights and today’s MapMaker Interactive map of the world’s “Lights at Night.”

Discussion Ideas

• A new atlas maps the impact on light pollution around the globe. What is light pollution?
  • Light pollution describes the artificial illumination of the night sky. Light pollution can limit visibility of faint stars and other celestial objects.
  • The terrific new study describes light pollution as the alteration of natural lighting levels caused by anthropogenic sources of light. Natural lighting levels are governed by natural celestial sources, mainly the Moon, natural atmospheric emission (airglow), the stars and the Milky Way, and zodiacal light.
    • The study also accounted for natural phenomena that may influence light pollution, including atmospheric conditions (such as the presence of storm clouds) and snow cover.

 

• Why is artificial light considered “pollution”?
  • The National Park Service identifies the night sky as a cultural resource, a natural resource, and an economic resource.
    • Cultural Resource: “Throughout history the night sky has shaped the beliefs and traditions of societies, from the myths of ancient Greece and the celestially-aligned architecture of Ancestral Puebloan civilizations to agricultural harvest festivals and nautical navigation records of sea voyages to new and distant lands.”
      • Through light pollution, “we have lost the connection with our roots, of literature, of philosophy, of science, of religion—all are connected with the contemplation of the night sky. A new generation can no longer appreciate this beauty,” says Fabio Falchi, author of the new study and a researcher at the Light Pollution Science and Technology Institute (ISTIL).
    • Natural Resource: Professional and amateur astronomers depend on dark skies for accurate Earth-based optical observations.
      • “Nearly half the species on Earth are nocturnal—active at night instead of during the day. The absence of light, natural or otherwise, is a key element of their habitat. Many species rely on natural patterns of light and dark to navigate, nest, mate, hide from predators, and cue behaviors … For example, migrating passerine birds reference stars to fly at night and can be disoriented by city lights and towers. Sea turtle hatchlings orient toward the brightest light on the beach, but instead of being drawn to the safety of sparkling waves on the ocean, they are often drawn toward roads and parking lots, where they quickly perish. And amphibians, with vision far more sensitive than that of humans, are prone to be disoriented by light.”
    • Economic Resource: Over-illumination (such as lights that shine upward into the sky, or that illuminate empty areas or buildings) wastes energy and money.
      • Medical researchers are still studying how light pollution impacts human health, through phenomena such as vision or sleep patterns. These impacts may have economic consequences.
      • “Astrotourism” is a small but growing industry that includes stargazing programs, night walks, full moon hikes, and other such activities.

 

• The new light pollution atlas is one of the first to account for the phenomenon of skyglow. What is skyglow?
  • Skyglow describes the diffuse glow, not arising from one specific source, that can be seen over urban areas.
  • Skyglow is produced as light is emitted to the sky, and reflected from clouds and the atmosphere itself back to Earth.

 

• Take a look at the lists of areas most impacted and least impacted by light pollution. What factors do you think contribute to the disparity?
  • Population density. Urban areas are much more impacted by light pollution.
  • Development. Regions with a stable and widespread electrical grid are more prone to light pollution. Homes, businesses, schools, and hospitals are often well-lit and even over-illuminated in the developed world.

 

• How can we combat light pollution?
  • Use timers to reduce or eliminate lighting when it’s not needed.
  • Direct light to areas that need it, and not upward (when lighting outdoor areas), or toward walls, windows, or ceilings (when lighting indoor areas).
  • Encourage businesses to eliminate “daytime lighting” outdoors.
  • Participate in Globe at Night, an international citizen-science campaign to raise public awareness of the impact of light pollution. Citizen scientists measure and submit their night-sky brightness observations. It’s easy to get involved—all you need is computer or smartphone, and these 5 Simple Steps!

 

TEACHERS TOOLKIT

Nat Geo: 80 Percent of Americans Can’t See the Milky Way Anymore

Nat Geo: World’s First Light-Pollution Law

Nat Geo: Lights at Night MapMaker Interactive map layer

International Dark-Sky Association: Intro to Lighting PowerPoint presentation for kids

International Dark-Sky Association: Materials for Educators (great collection of resources, lesson plans, and projects!)

Globe at Night citizen science project

National Park Service: Night Skies

(extra credit!) Science Advances: The new world atlas of artificial night sky brightness

Note: Current Event Connection is slowing down for the summer. Our column will continue to appear once or twice a week until mid-August. If you have an idea for a Current Event Connection, a recommendation for a good read, or want to share one of your MapMaker Interactive maps, let us know at education@ngs.org!