Science of Light

The sun is our main source of light. Photo by NASA.
The sun is our main source of light.


Learning more about the science of light and human vision will help us understand the value and fragility of natural lightscapes. During the day, the surface of the planet is bathed in light from the sun. The energy in sunlight drives weather, the water cycle, and ecosystems. But at night, in the absence of bright sunlight and clouds, our atmosphere turns transparent and allows us to see beyond our planet into the vastness of the cosmos.

light illuminating part of a wide cave passage from the ceiling which is covered with small lava sta
How Light Works

Lava tube at Craters of the Moon National Monument and Preserve, Idaho

A variety of fixtures and bulbs used for city lighting contribute to sky glow.
Light Pollution

Click on image above to learn about light pollution.

Milky Way at Chaco Canyon, New Mexico
Natural Light in the Night Sky

Natural Light in the Night Sky over Chaco Canyon

Last updated: June 17, 2024