Astronomers stumble in diplomatic push to protect the night sky

Negotiations to set up U.N. expert group on satellite megaconstellations continue behind the scenes
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A line of newly launched Starlink satellites lights up the sky over Dinosaur Provincial Park in Canada’s Alberta province in May 2021.ALAN DYER/AP

Astronomers’ efforts to get the United Nations to back guidelines to stop satellites from spoiling telescopes’ views have become bogged down in diplomatic bureaucracy. At a U.N. subcommittee meeting earlier this month in Vienna, delegates did not unanimously back the formation of an expert group to draft guidelines that could establish norms to help protect the night sky. Astronomers hope the United Nations will eventually endorse such guidelines, but they now must wait to see whether backroom negotiations can put the issue on the agenda ahead of a meeting in June.

“An expert group is still on the table” but national delegations “will need to achieve a consensus view,” says Andrew Williams, external relations officer for the European Southern Observatory.

Astronomers have been pushing for ways to protect the night sky since May 2019, when rocket company SpaceX launched its first batch of Starlink satellites, in what is now a “megaconstellation” of some 3500 satellites that provides worldwide internet service direct from orbit. Stargazers were alarmed by how bright the strings of satellites appeared as sunlight reflected off their shiny surfaces. Although most telescopes can avoid the satellites’ bright trails, studies showed survey telescopes with wide fields of view, such as the upcoming Vera C. Rubin Observatory in Chile, would have trouble avoiding the disruptive streaks.

Radio astronomers were also concerned. The frequency band used by Starlink is adjacent to a band reserved for radio astronomy and any spillover could impact observations. Radio observatories are sited in remote locations, far from the interference of TV transmitters and cell towers, but that cannot protect them from transmitters orbiting overhead.

SpaceX has taken steps to reduce impacts by coating satellite surfaces with less reflective materials and changing their orientation. And last month, the U.S. National Science Foundation and SpaceX announced a formal agreement to continue to work on the issue, with SpaceX striving to reduce the brightness of its satellites to seventh magnitude or less—just below what’s visible to the naked eye. The company will also provide astronomers with orbital information so observatories can steer clear of the passing satellites as much as possible, and it will try to limit impacts on U.S. radio observatories. But until nations establish international norms, there’s no guarantee that the many other satellite companies planning megaconstellations will be as responsible. The first giant BlueWalker 3 satellite, for example, launched in September 2022, rivals the brightest stars in the sky.

Led by the International Astronomical Union (IAU), astronomers have been lobbying the Committee on the Peaceful Uses of Outer Space (COPUOS), a U.N. body with 102 national members. At this month’s annual meeting of COPUOS’s science and technical subcommittee, IAU proposed that the subcommittee set up an expert group—which could include academic and industry representatives—to study the issue for 3 years before presenting guidelines. IAU also wants the subcommittee to keep the issue as a permanent agenda item for that period.

The subcommittee has done similar things before: A decade ago it set up a working group on the sustainability of space activities that drafted guidelines to limit the creation of space debris. Those guidelines were eventually adopted by COPUOS, and variations of them have now been incorporated into national laws in more than 45 countries, including most of the major spacefaring nations. (China has yet to adopt them.)

The IAU proposal was well received. Williams says it was endorsed by more than 30 national delegations. Some cited the need for pristine skies for cultural reasons, whereas others supported the notion of dark skies tourism. The delegate of the United States, home to many satellite operators, appreciated that the expert group would involve industry. “There was a unique coming together,” says Theunis Kotzé, head of legal at the Square Kilometre Array Observatory.

But IAU didn’t have it all its own way. According to observers, Russia’s delegate supported the need to protect astronomy, but suggested there was no need for a new expert group, and said the issue could be dealt with by the existing working group on long-term sustainability of space activities. That’s something IAU and other backers oppose because it already has a full workload and its membership excludes scientific and industry experts. “We need solutions that are feasible and acceptable to those who operate the satellites,” IAU’s Piero Benvenuti says.

Some delegates also expressed concern about adding another new item to the subcommittee’s already crowded agenda. As delegates debated on the last day of the 2-week session how to streamline the agenda to fit in a new item, the IAU proposal was beaten by the clock. With those issues unresolved, the proposal does not automatically go forward for approval at the main COPUOS meeting in June. Instead, the core group of delegations that put it forward, including Chile, Spain, and South Africa—all hosts of major research telescopes—along with IAU and other backers, have 4 months to build consensus and refine the proposal to make it clear why the issue needs its own expert group. “Overall, the result is successful, with such a strong support from so many countries,” Benvenuti says.

Kotzé says he is optimistic that these “small differences of opinion” can be resolved by then. “The mere fact that dark and quiet skies was discussed at the U.N. is incredible,” he says.


The Vera C. Rubin Observatory* in Chile, due to start collecting science data in 2022, faces the worst-case scenario because its detectors are both very sensitive and have incredible fields of view. The Rubin Observatory, after all, is designed to video the entire night sky every few days, ultimately collecting a decade's worth of reel in which astronomers hope to discover asteroids, supernovae, and many other transient events that might otherwise slip them by.

The Rubin Observatory therefore presents SpaceX with its biggest challenge, as Starlink satellites at their current brightness would saturate detectors and ruin whole images. For that reason, Tony Tyson (University of California, Davis) and others with Rubin Observatory have been communicating directly with SpaceX engineers, including providing them with target numbers to hit.

While coating the bright parts of the satellite didn't work, SpaceX hopes to do better with its plan for a Sun visor (initially called a Sun "umbrella). The visor provides the benefit of black paint by blocking sunlight from all of the white parts of the main body, as well as the antennas, while avoiding the thermal balance problems.

* Vera C. Rubin Observatory:

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Twilight photo of Rubin Observatory taken in April 2021. Credit: Rubin Obs./NSF/AURA

Rubin Observatory will advance science in four main areas: the nature of dark matter and understanding dark energy, cataloging the Solar System, exploring the changing sky, and Milky Way structure and formation.

Rubin Observatory will operate on an automated cadence, capturing an area the size of 40 full moons with each pair of 15-second exposures and returning to the same area of sky approximately every three nights. Over ten years of operations, hundreds of deep exposures will be acquired for every part of the visible sky. Dedicated computer facilities will process Rubin Observatory data in real time, issuing worldwide alerts within 60 seconds of detected changes in the sky. Prompt and data release products will be available to all U.S. and Chilean astronomers, and to Rubin Observatory’s in-kind contributors.

A subset of data will be widely available through the Rubin Observatory Education and Public Outreach (EPO) ( dynamic website portal, offering tools and activities for formal educators, citizen scientists, informal science centers, and the general public to engage, explore, and discover.

Rubin Observatory was the top-ranked large ground-based project in the 2010 Astrophysics Decadal Survey. Engineering and then science first light is expected in 2023 and full operations for the ten-year survey commencing in the second half of 2024. When operations begin, Rubin Observatory will be coordinated and managed by NSF’s NOIRLab. AURA operates the Vera C. Rubin Observatory for the National Science Foundation under a cooperative agreement.


Vera C. Rubin:
How Vera Rubin confirmed dark matter
This famous astronomer carved herself a well-deserved place in history, so why doesn’t the Nobel committee see it that way?

By Sarah Scoles | Published: Tuesday, October 4, 2016

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A young Vera Rubin was already observing the stars when she was an undergraduate at Vassar College, where she earned her bachelor's degree in astronomy in 1948. Archives & Special Collections, Vassar College Library

In the late 1970s, Vera Rubin and Kent Ford of the Carnegie Institution of Washington stared, confused, at the punch-card readouts from their observations of the Andromeda Galaxy. The vast spiral seemed to be rotating all wrong. The stuff at the edges was moving just as fast as the stuff near the center, apparently violating Newton’s Laws of Motion (which also govern how the planets move around our Sun). While the explanation for that strange behavior didn’t become clear to Rubin until two years later, these printouts represented the first direct evidence of dark matter.

Scientists now know that dark matter comprises some 84 percent of the universe’s material. Its invisible particles swarm and stream and slam through the whole cosmos. It affects how stars move within galaxies, how galaxies tug on each other, and how all that matter clumped together in the first place. It is to the cosmos like air is to humans: ubiquitous, necessary, unseen but felt. The discovery of this strange substance deserves a Nobel Prize. But, for Rubin, none has come, although she has long been a “people’s choice” and predicted winner.

In the past few years, scientists have gotten that free trip to Sweden for demonstrating that neutrinos have mass, for inventing blue LEDs, for isolating graphene’s single carbon layer, and for discovering dark energy. All of these experiments and ideas are worthy of praise, and some, like dark energy, even tilted the axis of our understanding of the universe. But the graphene work began in 2004; dark energy observations happened in the late ’90s; scientists weighed neutrinos around the same time; and blue LEDs burst onto the scene a few years before that. Rubin’s work on dark matter, on the other hand, took place in the 1970s. It’s like the committee cannot see her, although nearly all of astrophysics feels her influence.
Rubin is now 87. She is too infirm for interviews. And because the Nobel can only be awarded to the living, time is running out for her.

Emily Levesque, an astronomer at the University of Washington in Seattle who has spoken out about Rubin’s notable lack of a Nobel, says, “The existence of dark matter has utterly revolutionized our concept of the universe and our entire field; the ongoing effort to understand the role of dark matter has basically spawned entire subfields within astrophysics and particle physics at this point. Alfred Nobel’s will describes the physics prize as recognizing ‘the most important discovery’ within the field of physics. If dark matter doesn’t fit that description, I don’t know what does.”

There’s no way to prove why Rubin remains prize-less. But a webpage showing images of past winners looks like a 50th-reunion publication from a boys’ prep school. No woman has received the Nobel Prize in physics since 1963, when Maria Goeppert Mayer shared it with Eugene Wigner and J. Hans Jensen for their work on atomic structure and theory. And the only woman other than Mayer ever to win was Marie Curie. With statistics like that, it’s hard to believe gender has nothing to do with the decision.

Some, like Chanda Prescod-Weinstein of the Massachusetts Institute of Technology, have called for no men to accept the prize until Rubin receives it. But given the human ego and nearly million-dollar prize amount, that’s likely to remain an Internet-only call to action.

Rubin isn’t unfamiliar with discrimination more outright than the Nobel committee’s. Former colleague Neta Bahcall of Princeton University tells a story about a trip Rubin took to Palomar Observatory outside of San Diego early in her career. For many years, the observatory was a researcher’s man cave. Rubin was one of the first women to gain access to its gilt-edged, carved-pillar grandeur. But while she was allowed to be present, the building had no women’s restroom, just urinal-studded water closets.

“She went to her room, she cut up paper into a skirt image, and she stuck it on the little person image on the door of the bathroom,” says Bahcall. “She said, ‘There you go; now you have a ladies’ room.’ That’s the type of person Vera is.”

Rubin has continued to champion women’s rights to — and rights within — astronomy. “She frequently would see the list of speakers [at a conference],” says Bahcall, “and if there were very few or no women speakers, she would contact [the organizers] and tell them they have a problem and need to fix it.”

But, as Rubin told science writer Ann Finkbeiner for Astronomy in 2000, she is “getting fed up. . . . What’s wrong with this story is that nothing’s changing, or it’s changing so slowly.”

Rubin, born in 1928, first found her interest in astronomy when her family moved to Washington, D.C. Windows lined the wall next to her bed. She watched the stars move, distant and unreachable. “What fascinated me was that if I opened my eyes during the night, they had all rotated around the pole,” she told David DeVorkin in 1995 as part of the American Institute of Physics oral history interview series. “And I found that inconceivable. I just was captured.”

She started watching meteor showers and drew maps of the streaks, which striped the sky for a second and then were gone. She built a telescope and chose astronomical topics for English papers, using every subject as an opportunity to peer deeper into the universe. “How could you possibly live on this Earth and not want to study these things?” she wondered, retelling the story to DeVorkin.

While her parents supported her, it was a different story at school. When she told her physics teacher, for instance, that she had received a scholarship to Vassar College, he said, “As long as you stay away from science, you should do OK.”

She didn’t.

After receiving her bachelor’s degree from Vassar, Rubin enrolled in graduate school in astronomy at Cornell University in Ithaca, New York. Ensconced in Ithaca’s gorges and working with astronomer Martha Stahr Carpenter, Rubin began to hunt around for a master’s thesis idea. Carpenter was obsessed with galaxies and how their innards moved. “Her course in galaxy dynamics really set me off on a direction that I followed almost my entire career,” said Rubin.

One day, her new husband, Robert Rubin, brought her a journal article by astronomer George Gamow. In it, Gamow wondered, “What if we took the way solar systems rotate and applied it to how galaxies move in the universe?”

Rubin wondered, “What if, indeed?” and took that wonder a step further. She began to measure how galaxies moved. Did some cluster together in their travel through space — perhaps rotating around a pole, like the planets rotate around the common Sun? Was it random?

While gathering data, she found a plane that was denser with galaxies than other regions. She didn’t know it at the time, and no one else would discover it for years, but she had identified the “supergalactic plane,” the equator of our home supercluster of galaxies.

When she presented her thesis, William Shaw, one of her advisers, told her just two things: One, the word data is plural. Two, her work was sloppy. But, he continued, she should consider presenting it at the American Astronomical Society (AAS) meeting. Or, rather, she should consider having it presented for her. Because she was pregnant with her first child — due just a month before the meeting — and not a member of the society, he graciously volunteered to give a talk on her results. “In his name,” she clarified to DeVorkin. “Not in my name. I said to him, ‘Oh, I can go.’ ”

She called her talk “Rotation of the Universe,” ascribing the ambitious title to “the enthusiasm of youth,” as she recalled. At the AAS meeting, she didn’t know anyone, and she thought of herself as a different category of human. “I put these people in a very special class. They were professional astronomers, and I was not,” she said, showcasing a classic case of impostor syndrome, a psychological phenomenon in which people don’t feel they deserve their accomplishments and status and will inevitably be exposed as frauds. “One of the biggest problems in my life [during] those years was really attempting to answer the question to myself, ‘Will I ever really be an astronomer?’ ”

The “real astronomers” pounced on her result (except, notably, Martin Schwarzschild, who defined how big black holes are). “My paper was followed by a rather acrimonious discussion,” she told DeVorkin. “I didn’t know anyone, so I didn’t know who these people were that were getting up and saying the things they said. As I recall, all the comments were negative.”

Her paper was never published.

For six months after her first child was born, Rubin stayed home. But while she loved having a child, staying at home emptied her. She cried every time The Astrophysical Journal arrived at the house. “I realized that as much as we both adored this child, there was nothing in my background that had led me to expect that [my husband] would go off to work each day doing what he loved to do, and I would stay home with this lovely child,” she said to DeVorkin. “I really found it very, very hard. And it was he who insisted that I go back to school.”

She was accepted into a Ph.D. program at Georgetown University in Washington, D.C., and she discovered that galaxies did clump together, like iron filings, and weren’t randomly strewn. The work, though now part of mainstream astronomy, was largely ignored for decades; that lack of reinforcement perhaps contributed to her lingering, false feeling that she wasn’t a real astronomer. As she described it, “My husband heard my question often, ‘Will I ever really be an astronomer?’ First I thought when I’d have a Ph.D., I would. Then even after I had my Ph.D., I wondered if I would.”

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Rubin operates the 2.1-meter telescope at Kitt Peak National Observatory. Kent Ford's spectograph is attached so they can measure the speed of matter at different distances from galaxies' centers.

In 1965, after a stint as a professor at Georgetown, Rubin began her work at the Carnegie Institution’s Department of Terrestrial Magnetism in Washington, D.C., where she met astronomer Kent Ford and his spectacular spectrometer, which was more sensitive than any other at the time.

A spectrometer takes light and splits it up into its constituent wavelengths. Instead of just showing that a fluorescent bulb glows white, for instance, it would show how much of that light is blue and how much yellow, and which specific wavelengths of blue and yellow. Ford’s spectrometer stood out from others at the time because it employed state-of-the-art photomultipliers that let researchers study small regions of galaxies, and not simply the entire objects.

With this device, Ford and Rubin decided to look at quasars — distant galaxies with dynamic, supermassive black holes at their centers. But this was competitive work: Quasars had just been discovered in 1963, and their identity was in those days a mystery that everyone wanted to solve. Rubin and Ford didn’t have their own telescope and had to request time on the world-class instruments that astronomers who worked directly for the observatories could access all the time. Rubin didn’t like the competition.

“After about a year or two, it was very, very clear to me that that was not the way I wanted to work,” she told Alan Lightman in another American Institute of Physics oral history interview. “I decided to pick a problem that I could go observing and make headway on, hopefully a problem that people would be interested in, but not so interested [in] that anyone would bother me before I was done.”

Rubin and Ford chose to focus on the nearby Andromeda Galaxy (M31). It represented a return to Rubin’s interest in galaxy dynamics. “People had inferred what galaxy rotations must be like,” said Rubin, “but no one had really made a detailed study to show that that was so.” Now, because of Ford’s out-of-this-world spectrograph, they could turn the inferences into observations.

When they pointed the telescope at M31, they expected to see it rotate like the solar system does: Objects closer to the center move faster than ones toward the edge. Mass causes gravity, which determines the speed of rotation. Since most of the stars, dust, and gas — and therefore gravity — is clustered in the middle of galaxies, the stuff on the periphery shouldn’t feel much pull. They concentrated their observations on Hydrogen-II (HII) regions — areas of ionized hydrogen gas where stars have recently formed — at different distances from the galaxy’s center. But no matter how far out they looked, the HII regions seemed to be moving at the same speed. They weren’t slowing down.

“We kept going farther and farther out and had some disappointment that we never saw anything,” says Ford. “I do remember my puzzling at the end of the first couple of nights that the spectra were all so straight,” said Rubin, referring to the unchanging speed of the various HII regions.

They didn’t know what, if anything, it meant yet.

The project took years and involved treks westward to telescopes. Ford recalls flying to Flagstaff, Arizona, dragging the spectrograph from the closet, working for a few nights at Lowell, and then throwing the instrument into a Suburban so they could drive it to Kitt Peak. “We both thought we were better at guiding the telescope,” he says. They raced each other to be first to the eyepiece.

The data came out on punch cards, which Rubin spent hours analyzing in a cubbyhole beneath a set of stairs. They all showed the same thing.

Rubin and Ford moved on from M31 to test other galaxies and their rotation curves. Like an obsessive artist, each painted the same picture. Although the result contradicted theory, and although they didn’t understand what it meant, no one doubted their data. “All you had to do was show them a picture of the spectrum,” Rubin told Lightman. “It just piled up too fast. Soon there were 20, then 40, then 60 rotation curves, and they were all flat.”

Dark matter existed as a concept, first proposed by astronomers like Jan Oort in 1932 and Fritz Zwicky in 1933, who also noticed discrepancies in how much mass astronomers could see and how much physics implied should be present. But few paid their work any attention, writing their research off as little more than cosmological oddities. And no one had bagged such solid evidence of it before. And because no one had predicted what dark matter’s existence might mean for galaxy dynamics, Rubin and Ford initially didn’t recognize the meaning of their flat rotation curves.

“Months were taken up in trying to understand what I was looking at,” Rubin told journalist Maria Popova. “One day I just decided that I had to understand what this complexity was that I was looking at, and I made sketches on a piece of paper, and suddenly I understood it all.”

If a halo of dark matter graced each galaxy, she realized, the mass would be spread throughout the galaxy, rather than concentrating in the center. The gravitational force — and the orbital speed — would be similar throughout.

Rubin and Ford had discovered the unseeable stuff that influences not only how galaxies move, but how the universe came to be and what it will become. “My entire education highlighted how fundamental dark matter is to our current understanding of astrophysics,” says Levesque, “and it’s hard for me to imagine the field or the universe without it.”

Within a few years of the M31 observations, physicists like Jeremiah Ostriker and James Peebles provided the theoretical framework to support what Rubin and Ford had already shown, and dark matter settled firmly into its celebrated place in the universe.

In more recent years, the Planck satellite measured the dark matter content of the universe by looking at the cosmic microwave background, the radiation left over from the Big Bang. The clumps of matter in this baby picture of the universe evolved into the galaxy superclusters we see today, and it was dark matter that clumped first and drew the regular matter together.

Data from galaxy clusters now also confirms dark matter and helps scientists measure how much of it exists within a given group — a modern echo of Zwicky’s almost forgotten work. When light from more distant sources passes near a cluster, the gravity — from the cluster’s huge mass — bends the light like a lens.

The amount of bending can reveal the amount of dark matter.

No matter which way or where scientists measure Rubin’s discovery, it’s huge.

And while no one knows what all the dark matter is, scientists have discovered that some small fraction of it is made of neutrinos — tiny, fast-moving particles that don’t really interact with normal matter. Measurements from the cosmic microwave background, like those being taken by experiments called POLARBEAR in Chile and BICEP2 and BICEP3 in Antarctica, will help pin down how many neutrinos are streaming through the universe and how much of the dark matter they make up.

Some setups, like the Gran Sasso National Laboratory in Italy and the Deep Underground Science and Engineering Laboratory in South Dakota, are trying to detect dark matter particles directly, when they crash into atoms in cryogenically cooled tanks filled with liquefied noble gases. So far, they haven’t managed to capture a dark matter particle in action. But researchers are taking dark matter — whatever it is — into account when they think about how the universe evolves.

The Nobel committee may overlook Rubin, passing by her as if they can’t see what all of astrophysics feels. But that won’t hurt her legacy, says Levesque: It will hurt the legacy of the Nobel itself. “It would then permanently lack any recognition of such groundbreaking work,” Levesque says.

Rubin herself has never spoken about how she deserves a Nobel Prize. She simply continued her scientific work until recently, all the while influencing the origins, evolutions, and fates of other scientists. “If they didn’t get a job or they didn’t get a paper published, she would cheer people up,” says Bahcall. “She kept telling her story about how there are ups and downs and you stick with it and keep doing what you love doing.”

Rubin, herself, loves trying to understand the universe, and in doing so, she has changed everyone’s understanding of it. That carries more weight than some medal from Sweden. But let Sweden recognize that for what it is: worthy of a prize.


Shortly after this article was published, Vera C. Rubin passed away on December 25, 2016. She will always remain in my Pantheon of heroes for her magnificent work. Her failure to garner a Nobel Prize says more about the Committee than it does Rubin.


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