The bright electric lights of Hermosillo, Mexico, nearly drown out the sunset.

Photograph by Ana Encinas, MyShot
  • On June 1, 2002, the world's first light-pollution law was enacted in the Czech Republic. The “Protection of the Atmosphere Act” required all lighting fixtures to have shielding to prevent light emission “above the horizontal.”


    Laws against light pollution benefit astronomers. When light bounces around the atmosphere, it makes seeing things through telescopes much more difficult. Astronomers need to have a clear view of the stars and planets above.


    Less light pollution not only helps astronomers—it helps consumers. Shielded lights do their job more efficiently—they shine more brightly on what we actually want to be lit. More efficient lighting also saves energy, reducing costs and conserving natural resources.

  • Term Part of Speech Definition Encyclopedic Entry
    astronomer Noun

    person who studies space and the universe beyond Earth's atmosphere.

    atmosphere Noun

    layers of gases surrounding a planet or other celestial body.

    Encyclopedic Entry: atmosphere
    conserve Verb

    to save or use wisely.

    consumer Noun

    person who uses a good or service.

    efficient Adjective

    performing a task with skill and minimal waste.

    emission Noun

    discharge or release.

    energy Noun

    capacity to do work.

    horizontal Adjective

    left-right direction or parallel to the Earth and the horizon.

    natural resource Noun

    a material that humans take from the natural environment to survive, to satisfy their needs, or to trade with others.

    telescope Noun

    scientific instrument that uses mirrors to view distant objects.