The phenomenon of being unable to see stars in city centers, while observing a plethora of stars, including the mesmerizing Milky Way, in suburban or mountainous regions, can be attributed to light pollution.

This concept is encapsulated by the signal-to-noise ratio, which represents the ratio of the desired signal (stars) to unwanted noise (artificial light).

In urban areas, the night sky is significantly brighter due to light pollution, thereby reducing the signal-to-noise ratio and rendering faint stars, including the Milky Way, invisible to the unaided eye or telescopes. This underscores the detrimental impact of light pollution on astronomical observations.

Telescopes, vital tools for astronomical research, are typically situated in locations characterized by favorable weather conditions, minimal atmospheric interference, and dark skies. However, artificial light sources inundate urban environments, illuminating the night sky to levels that impede astronomical observations. The increased sky brightness necessitates longer exposure times to capture faint celestial objects, thereby diminishing observing efficiency and limiting scientific research opportunities. In severe cases, faint objects may remain undetectable despite prolonged exposure—a testament to the profound influence of light pollution on astronomical endeavors.

The proliferation of artificial light sources at night, facilitated by the advent of artificial light worldwide, has yielded numerous societal benefits, including enhanced safety and urban development. Nevertheless, excessive artificial illumination contributes to light pollution, surpassing functional lighting requirements and posing novel challenges to both natural and built environments. Extensive research has highlighted the adverse effects of light pollution on human health, wildlife, and ecosystems. Notably, the disruption of natural day-night cycles can detrimentally affect physiological processes, such as melatonin secretion, leading to sleep disorders and associated health conditions.

Light pollution encompasses various phenomena arising from improperly designed lighting installations, including glare pollution, ray pollution, light flooding, and visual monotony. Scattering exacerbates sky brightness, particularly when light sources emit photons vertically upwards or downwards, reflecting off surfaces and contributing to atmospheric haze. Importantly, light pollution not only impacts human well-being but also disrupts crucial behaviors in wildlife, such as foraging and mating activities, further underscoring the urgency of addressing this pervasive environmental issue.

As awareness of the multifaceted impacts of light pollution grows, concerted efforts to mitigate its effects and implement sustainable lighting practices become imperative. Prioritizing the conservation of dark sky environments and promoting responsible lighting strategies can safeguard biodiversity, protect human health, and preserve the intrinsic beauty of the night sky. By recognizing the significance of combating light pollution, society can forge a path towards a more harmonious coexistence between artificial illumination and the natural world.

In addition to its implications for astronomy and human health, light pollution also poses ecological challenges by disrupting the behavior and habitats of various species. Nocturnal animals, reliant on darkness for navigation and hunting, face altered foraging patterns and increased vulnerability to predation. Artificial light can interfere with the reproductive cycles of insects and birds, impacting mate selection and breeding success. Marine ecosystems are similarly affected, with artificial illumination disrupting the behavior of marine organisms and exacerbating the threat of habitat degradation. Addressing light pollution is essential for safeguarding biodiversity and maintaining the integrity of ecosystems worldwide.