Dark Skies and the "Olympics of Astronomy"

Image credit: Dark Sky Consulting
1913 words / 8-minute read

Summary: As athletes gathered in Paris for the 2024 Olympic Summer Games, the "Olympics of Astronomy" convened half a world away. At the International Astronomical Union's 32nd General Assembly, dark skies was on the agenda. Read about astronomers' involvement in the dark skies movement and how related concerns were top of mind at this year's event.​

The world recently watched the spectacle of the 2024 Olympic games. Assembling the world's best athletes once every four years sets the Games apart from many other athletic competitions. The Olympic flame extinguished, another long period commences before they meet again in another world city.
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The world astronomy community has its own version in the form of a similar gathering of greats with a long period between. The International Astronomical Union's General Assembly, held somewhere in the world every three years, is sometimes called the "Olympics of Astronomy". The events draw astronomers from all over the world for meetings where many would only ever encounter one another. Since dark skies were on the agenda at the latest edition, it's a good time to catch up here on efforts to protect astronomy for the benefit of future generations. 

A long history of leading the way

The International Astronomical Union, or IAU, is the world's main professional body representing astronomers. Founded in the wake of the First World War, it now represents over 12,000 people in astronomy and related fields. Their professional predecessors were among the first to sound the alarm about light pollution. Astronomers made some of the first descriptions of its effects on the night sky. The earliest accounts come from the 19th century in the era of gas lighting. By the turn of the 20th century, electric light quickly became a new scourge. Astronomical observatories moved out of the capitals of Europe for more rural locations. Some viewed this as the price of progress while wondering whether the price was too high.
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The scientific study of light pollution began in the 1960s and 1970s, and again astronomers led the way. One of the first scholarly mentions of light pollution was a little over 50 years ago in the pages of the journal Science. Astronomers worked to understand the influences that had been brightening skies over observatories for decades. And they put energy into changing public policies in and around observatory sites. For instance, the city of Flagstaff, Arizona, enacted what may be the world's first outdoor lighting law in 1958. Nearby Lowell Observatory played no small part in that effort.

Astronomers get organized

IAU was a little late to the party in recognizing the seriousness of light pollution. It contributed to the the Starlight Declaration of 2007, which called access to dark skies “a fundamental socio-cultural and environmental right”. At its 27th General Assembly in 2009, the IAU adopted a resolution on light pollution. It urged its members to work to reduce light pollution from the local to international levels. And in 2020-21, it helped arrange two international workshops on the subject. The events addressed the connection between light pollution and cultural heritage, "dark sky oases", astrotourism, and the bio-environment.
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The IAU has also built dark skies into its formal activities. In 1973 it set up Commission 50, dedicated to "Protection of Existing & Potential Observatory Sites". In 2018 it became Inter-Division B-C Commission B7, reflecting the duel influences of Commissions B ("Facilities, Technologies and Data Science") and C ("Education, Outreach and Heritage"). In the early 2020's IAU began to realize the threat posed to astronomy by large satellite constellations, which we previously wrote about here. In response it established the Centre for the Protection of the Dark and Quiet Sky from Satellite Constellation Interference (CPS).

Addressing a new threat from above

As athletes were competing in Paris, astronomers from 107 countries gathered in Cape Town, South Africa, for the 2024 General Assembly. Besides dedicated sessions about light pollution and "Dark and Quiet Skies", these themes recurred in other programming during the two weeks of the General Assembly. Each of the IAU Offices (for Development, Outreach and Education) included aspects of these topics in their offerings.

CPS hosted a session early in the General Assembly dedicated to progress on the satellite issue. Richard Green, Interim CPS Director, opened the session with a summary of the status quo and developments since establishment of the Centre. Each of the four CPS "hubs", or sections, put on presentations during the daylong session. This was further supported by a poster session with a variety of results across CPS technical, policy and community engagement efforts. The session concluded with the perspectives of figures in the commercial space industry who described their actions taken by companies to reduce the impact of satellites on astronomy.

Richard Green (CPS Interim Director) opens the CPS session with a summary presentation.

Some common themes emerged. CPS touted its achievements in encouraging the industry to find creative solutions to mitigate potential harms to the night sky. CPS leaders called for more dialog and engagement with industry as the way to get the best outcomes. Technical presentations evaluated mitigations attempted to date. And space policy experts examined possibilities for affecting change in a challenging global regulatory climate. In particular, they pointed to the gradual emergence of best management practices among industry participants. These informal or "soft" approaches may have the best chance of success.
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At the same time, other presenters took a more skeptical point of view, criticizing elements of the engagement between astronomers and the industry. They pointed out inadequate attention to the issue among many astronomers. Lively exchanges between participants pulled at all the threads involved: legal, technical, and commercial. It was clear that the players are still far from agreement on some points. It's also the case that there is much we don't know about the broader problem. That includes the "carrying capacity" of orbital space and what effects re-entering satellites will have on Earth's upper atmosphere. Yet all agree that more satellites will be in orbit in the future, and we still lack the means of ensuring the sustainable development of space. ​

Ensuring the future of astronomical discovery

Later in the General Assembly dedicated sessions on light pollution took place. Inter-Division B-C Commission B7 held a business meeting to discuss strategy in the next 'triennium', or three year period of IAU activities. Its leadership acknowledged that much of the Commission's attention focused on the satellite problem in the previous triennium. It aimed to sketch out the major pieces of a strategic plan for 2024-27. Freeform discussion among the meeting attendees followed.

Many ideas came up: opportunities to inform the framing of national light pollution legislation; better quantifying the cost to astronomy from light pollution; and standardizing the ways we measure and report light pollution impacts on astronomy. Those involved are also struggling with the degree to which their advocacy should directly address environmental concerns.

Supporters see that strategy as one that may prompt people to care about light pollution in ways that astronomy alone won't. The IAU itself is changing. It now often looks outward and engages with society beyond the community of professional astronomers alone. To do so calls for them to avoid excluding audiences from certain spaces because astronomers are "the experts".

Samyukta Manikumar (IAU Office of Astronomy for Development) leads an "unconference" session on astrotourism and dark skies.

On the last day of the General Assembly, the IAU Executive Committee Working Group on Dark & Quiet Sky Protection convened another daylong session. The format was again a mix of presentations, posters and freely flowing discussion among participants. Nearly all agreed on the need to broaden the appeal of dark night skies and the protections from light pollution they need.

The development of astrotourism, a form of sustainable tourism oriented toward night-sky viewing, is seen as a key element in protecting more places in the world. The need for well-crafted and implemented outdoor lighting policies is acute. But several speakers also noted that people most affected by those policies should be consulted as a matter of basic democratic principles.

Lastly, the session looked beyond both our home planet and the wavelengths of light we can see with our eyes alone. The quiet part of "Dark and Quiet Skies" refers to radio frequency interference (RFI). This is the equal of light pollution in the radio part of the electromagnetic spectrum. Radio astronomers continue to suffer interference from diverse sources of artificial radio energy on the ground. But now they also find their observations under attack from above. Yet ways to focus the public's attention on RFI threats to radio astronomy remains elusive. Many people are simply unaware of the existence of radio astronomy, much less of RFI.
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Many of these threats to astronomy may play out again as humanity establishes a permanent presence in the cosmos. Plans to commercially develop the Moon, for example, are ramping up fast. Astronomers have long prized access to the Moon as the site of future telescopes with exquisite sensitivity. Such facilities could revolutionize our understanding of the universe. But they now face prospects like RFI from satellites in orbit around the Moon and damage from lunar dust kicked up by various activities. There is still a window of opportunity to protect the Moon from interference that would impact astronomy. The time remaining to protect the most vulnerable sites is running out. The IAU has established a Working Group on Astronomy on the Moon whose work is just beginning. ​

Reflections on past, present and future

Astronomers were the vanguard in sounding the alarm about light pollution. And for good reason: it threatened the success of their enterprise. Now of course we have powerful space telescopes situated far above our planet. But we still rely on their ground-based counterparts to be the workhorses of research and discovery. And even the most remote of those facilities is under assault by light pollution.

There are many takeaways on the subject of dark (and quiet) skies from two weeks in Cape Town for this year's IAU General Assembly. It seems that many astronomers don't pay a lot of attention to the issue, if they ever did. While the dark skies sessions were well-attended, they faced competition from science sessions held on the same days and times. The General Assembly offers a jam-packed schedule that inevitably involves conflicts among parallel sessions vying for participants' attendance.

​To some astronomers we talked to, putting their attention on dark and quiet skies feels like work that they often assume someone else is (or should be) doing. They face their own struggles with inadequate research funding and an unstable labor market. That was all the more evident among attendees from developing economies that don't enjoy the comparative luxuries of their North American and European colleagues. It's not that they don't care about light pollution. But they rarely have time to think about it, much less to take action.

The satellite problem has thrown a new complication into the mix. Despite the efforts of organizations like CPS, it has even less recognition among astronomers than ground-based light pollution. Some wondered aloud why the community failed to expect the threat, which forced it to play defense from the beginning. Yet there is still hope that the IAU will lead on all these issues and to come out more forcefully in support (and defense) of astronomy and astronomers everywhere.
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We're entering an era unprecedented in the history of astronomy. The biggest telescopes ever built will soon see first light. Machines like the James Webb Space Telescope are pushing the frontiers of discovery nearly to the origin of the universe itself. Computing power is cheap, allowing us to make very sophisticated models to understand the physics of the cosmos. And yet it is all threatened by forces from beyond and above. Astronomers still hold a place of special fascination and even reverence among the public. Will they use their status to rally that public in support of their science? The outcome will determine the very future of astronomy itself.

The IAU flag is passed to the hosts of the next IAU General Assembly, to be held in Rome, Italy, in August 2027.