The Vanishing Night: How Light Pollution is Erasing the Stars
A growing body of evidence indicates that artificial light pollution is increasing globally, reducing the visibility of stars, disrupting ecosystems, and affecting cultural and scientific practices that depend on dark night skies.
Scope and Trends
Scientific data shows a clear upward trend in artificial light at night. A NASA-funded study published in Nature in April analyzed over 1.1 million satellite images and found that global artificial light at night increased by approximately 16% between 2014 and 2022.
In North America and Europe, astrophotographer Alex Cherney reported a 9.6% annual increase in average sky brightness between 2011 and 2021. The number of artificial satellites orbiting Earth is currently around 12,000, with projections suggesting this number could rise to approximately 100,000 within a decade, further complicating astronomical observation.
A 2016 study in Science Advances found that Australia had the lowest proportion of light-polluted land among G20 nations. However, the same study indicated Australia had among the highest per-capita contributions to light pollution.
Impacts on Visibility and Astronomy
The increase in light pollution is obscuring the night sky for a significant portion of the global population. Over a third of the Earth's population is reportedly unable to see the Milky Way from their homes. In Australia, an estimated 75% of children live in urban areas where light pollution limits their view of stars.
Dr. Ken Wishaw, a former medical specialist, stated that on a clear winter night in central Brisbane, Sydney, or Melbourne, one would see approximately nine stars. He contrasted this with the Sunshine Coast International Dark Sky Reserve, where he said 3,000 stars are visible.
This reserve, spanning over 870 square kilometers, is Queensland's first official designation by DarkSky International and is currently under development. Initial surveys showed 95% community support.
Melbourne teacher Liam Murphy reported that many of his students are unaware that the Milky Way is visible in the sky. Astrophotographer Leonel Padron noted that some individuals express skepticism about the authenticity of his photographs due to their unfamiliarity with a truly dark sky.
Impact on Indigenous Knowledge and Cultural Practices
Light pollution is affecting Indigenous cultural practices that rely on celestial observation. Kai Lane, a 24-year-old Yorta Yorta and Barapa Barapa man, reported that only a few stars are visible from Geelong, Victoria. He stated that the dark patches of the Milky Way trace the Indigenous constellation Emu in the Sky, which the Barapa Barapa use as a signal for when to collect emu eggs and when the breeding season ends.
Wajarri elder Dawn Hamlett from Western Australia described how her ancestors used the Southern Cross as a compass and relied on celestial markers like the Emu in the Sky to understand seasons and gather food.
Kai Lane, who also runs cultural heritage workshops, said that light pollution is rarely included in the science curriculum. He reported simulating the obscuring of constellations with a white sheet to teach students about the effect.
Impact on Ecosystems
Artificial light is also impacting marine and terrestrial ecosystems. Associate Professor Mariana Mayer Pinto from UNSW studies how artificial light affects marine ecosystems. She noted that light affects the growth of kelp, a key habitat former in the Great Southern Reef, and that, combined with warming, it increases mortality rates. She also stated that seabirds become disoriented by artificial light.
Marnie Ogg, founder and director of the Australasian Dark Sky Alliance, stated that LED billboards and solar-powered lights are major threats to the night environment.
Legislative and Mitigation Efforts
In Australia, a petition for national light pollution legislation gathered over 12,000 signatures and was submitted to the House of Representatives in September 2024. In December, Environment Minister Murray Watt responded that the government recognizes the issue and noted the suggestion for further national legislation.
Minister Watt stated: "The Australian government recognises that excessive or poorly designed lighting can affect human health, disrupt ecosystems, and contribute to energy waste and emissions."
At the local level, approximately 16 local governments in Western Australia have implemented dark-sky accredited lighting policies. These policies advocate for warm-colored bulbs, motion sensors, and downward-focused streetlights to minimize light pollution.
Marnie Ogg reported a 10% reduction in light pollution since 2018 at Palm Beach, Sydney, following the creation of an Urban Night Sky Place by the Northern Beaches Council.
Retired Royal Australian Navy veteran Brendan Naylor explained that celestial navigation by stars is still taught in the navy. Astrophotographer Greg Rowney observed noticeable changes in sky visibility even in traditionally dark areas north of Perth.
A Historical Event
A notable event illustrating the extent of lost sky visibility occurred on January 17, 1994. A 6.7 magnitude earthquake caused a power blackout in Los Angeles. Dr. Ed Krupp, director of Griffith Observatory, noted that this event revealed a star-filled sky to many residents who had never witnessed it before, and he observed that this experience unsettled many.