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Light and Astronomy

Light pollution interferes with ground-based astronomy in several ways. See also our discussion of light pollution in the context of Cities.

Satellites and Light Pollution

Low-earth satellites, especially the Internet collections such as Starlink that are now under development, raise concerns about light pollution that could interfere with ground-based astronomy 1.

Problem:
Light Pollution
Solution:
Satellite Database

As present, some but not all U.S. Federal agencies apply the National Environmental Policy Act (NEPA) to orbital impacts. It is considered to legislatively mandate that this always happens 1.

LEDs and Light Pollution

Light-emitting diodes (LEDs) have greatly improved energy efficiency over alteratives, but they emit more light at lower (blue) wavelengths, causing greater skyglow disruption to wildlife's circadian rhythm per unit of lighting.

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Source: Hall et al. 2.

White LEDs pose a tradeoff between energy efficiency, visibility, and ecological impact, for which there is not an obvious solution in general 3. White LEDs are also more visually pleasing to humans than other lighting options 4. Blue-free white LEDs, which could retain high energy efficiency while reducing ecological disruption, are an active area of development 5.

Light Pollution in the Radio Spectrum

Radio telescopes, which have provided enormous understanding of the universe and continue to do so, are sensitive to radio interference, such as from satellites 2. The International Telecommunication Union restricts radio activity that would cause more than a 10% error on measurements from radio telescopes 6. Additionally, state and national laws establish Radio Quiet Zones around radio telescopes, which greatly restrict wireless activities 6.

References

  1. NOIRLab. "Satellite Constellations 2 Workshop". July 12-16, 2021. ↩ ↩2

  2. Hall, J., Allen, L., Arion, D., Barentine, J., Caton, D., Liszt, H., Lowenthal, J., McKenna, D., Pipkin, A., Seitzer, P., Walker, C. "Light Pollution, Radio Interference, and Space Debris: Threats and Opportunities in the 2020s". Bulletin of the AAS 51(7). September 2019. ↩ ↩2

  3. Peña-García, A., Sędziwy, A. "Optimizing Lighting of Rural Roads and Protected Areas with White Light: A Compromise among Light Pollution, Energy Savings, and Visibility". The Journal of the Illuminating Engineering Society 16(2). 2020. ↩

  4. Pawson, S. N., Bader, M. K.-F. "LED lighting increases the ecological impact of light pollution irrespective of color temperature". Ecological Applications 24(7). October 2014. ↩

  5. Menéndez-Velázquez, A., Morales, D., García-Delgado, A. B. "Light Pollution and Circadian Misalignment: A Healthy, Blue-Free, White Light-Emitting Diode to Avoid Chronodisruption". International Journal of Environmental Research and Public Health 19(3). February 2022. ↩

  6. van Driel, W. "Radio quiet, please! – protecting radio astronomy from interference". Proceedings of the International Astronomical Union, S260), pp. 457-64. January 2009. ↩ ↩2