Recently the International Astronomical Union (IAU) has adopted a resolution aimed at enhancing the protection of the dark and quiet skies.
During the 32nd General Assembly of the IAU, held for the first time in Africa, the resolution to protect the night sky from light and radio pollution was a popular topic. As the IAU’s newly adopted resolution highlights, the threats to our night sky are diverse and growing. The most visible threat comes from light pollution, exacerbated by the global shift to LED technology.
“A problem for us with light pollution on the ground is the ongoing world transition to LED technology, which has made light at night very inexpensive to consume,” stated Dr. John Barentine, Executive Officer and Principal Consultant at Dark Sky Consulting.
Over the past decade, the brightness of the night sky has increased by about 10 percent annually worldwide, a trend that threatens not only astronomical research but also human health and biodiversity.
The widespread adoption of LED lighting has improved energy efficiency but has also led to excessive and often unnecessary illumination. This can be particularly seen in industrial areas, where floodlights are kept on throughout the night, regardless of human activity. The impact of light pollution extends beyond obstructing our view of the stars, it disrupts natural circadian rhythms, leads to sleep disorders, and negatively affects wildlife that depends on natural light cycles.
Efforts to raise awareness about the importance of preserving dark skies have faced challenges, especially in communicating the broader impacts of light pollution. “One of the biggest challenges has been raising awareness about the importance of dark sky preservation. While people more intuitively understand how light pollution affects astronomy, its effects on biodiversity, health, and heritage are harder to communicate,” said Carol Nyaguthii, Secretary of DarkSky Kenya.
Countries in the Global North are now focused on mitigating the damage caused by light pollution, while nations like Kenya, where electrification is still expanding, have the opportunity to implement lighting solutions that do not compromise the integrity of the night sky. Nyaguthii said that with careful planning and the use of innovative solutions like timers, motion sensors, and color adjustments, it is possible to have effective lighting without contributing to light pollution.
However, light pollution from the ground is only part of the problem. The rapid increase in the number of satellites orbiting the Earth is creating new challenges for astronomers. The rise of mega-constellations, like SpaceX’s Starlink, has dramatically altered the night sky, with the potential to obstruct astronomical observations even in designated dark-sky areas. By June 2024, there were 11,780 satellites in orbit, with 6,050 belonging to Starlink. As more satellites are launched, the risks to both optical and radio astronomy increase.
“The sky is a resource, I think, that’s available to everybody. And there’s so much out there in astronomy that we don’t yet know. The increased number of satellites poses a risk to our ability to see and learn more things,” said Dr. Wendy Williams, a scientist at the SKA Observatory.
The situation is compounded by the lack of comprehensive regulations to limit light and radio pollution from satellites.
In the United States, the Federal Communications Commission requires satellite operators to have a coordination agreement with the National Science Foundation to minimize light pollution. However, this agreement lacks enforceable standards, leaving companies with the ability to claim they have made good faith efforts without necessarily reducing their impact on the night sky.
Despite these challenges, there is hope. Companies involved in satellite operations have shown a willingness to engage with astronomers and consider changes to satellite design and operations to minimize their impact on the night sky.
“We don’t want to roll back any progress,” noted Dr. Barentine. “The satellite operators have a right to be in space, just as we have a right to access space for astronomy purposes.”
The need for clear, enforceable regulations is important, especially as the number of satellites in orbit continues to grow. Dr. Lewis Ball, Director of Operations for the SKA Organisation, pointed out that the current one-to-one interactions between astronomers and satellite operators will become unsustainable as the number of operators increases. He emphasized the importance of regulatory frameworks to manage this growing challenge.
Efforts are underway to address these concerns at the international governance level. The European Space Agency is updating its space debris mitigation standards to include provisions for protecting dark and quiet skies. Dr. Williams, who represents the European Southern Observatory at the United Nations Committee on the Peaceful Uses of Outer Space, expressed optimism that these issues will be formalized within international frameworks.
“The most precious resource for astronomers is the sky. This remained unchanged for millennia. But it is no longer the case. The sky is threatened by light pollution and satellite constellations,” noted Willy Benz, incoming IAU president.
The IAU, along with partners like the NSF Noirlab and SKAO, is pushing for international regulations to protect this important resource.