If we go from 14,000 to 1.7 million, we are really going to have problems.
For as long as humans have looked upward, the night sky has served as both a scientific instrument and a mirror for our place in the cosmos. Now, plans to launch 1.7 million commercial satellites — from internet networks to space-based mirrors designed to illuminate the Earth at night — threaten to erase that shared inheritance. Researchers at the European Southern Observatory warn that without regulatory intervention, the darkness humanity has always known will give way to a permanent artificial twilight, rendering major observatories obsolete and severing ecosystems from the rhythms they depend on.
- Plans to launch 1.7 million satellites — up from 14,000 today — would flood the night sky with streaking light, making the majority of images from the world's most powerful telescopes scientifically worthless.
- One company, Reflect Orbital, proposes 50,000 mirror-equipped satellites to bounce sunlight back to Earth at night, a scheme that alone would brighten the entire night sky fourfold and render Venus-bright objects visible from every corner of the globe.
- The consequences reach beyond astronomy: disrupted biological rhythms, collapsing dark-dependent ecosystems, and the looming risk of Kessler syndrome — a cascade of orbital collisions that could lock humanity out of certain space lanes for generations.
- Astronomers from the ESO, the Royal Astronomical Society, and the International Astronomical Union are calling for a hard cap of 100,000 satellites and mandatory dimming technology, framing the stakes plainly: 'For optical astronomy, this is an existential threat.'
- The decision now rests with the US Federal Communications Commission, which must rule on applications from SpaceX and Reflect Orbital — a regulatory moment that will determine whether the night sky remains a commons or becomes commercial infrastructure.
Roughly 14,000 satellites currently orbit Earth, most of them recent arrivals from Starlink and other commercial ventures. That number is about to become a footnote. Companies are preparing to launch 1.7 million more, and the European Southern Observatory has published research this week making clear what that means for anyone who studies the sky: it breaks astronomy.
The mechanics are straightforward. A satellite crossing a telescope's field of view leaves a bright streak across the image, erasing whatever lay behind it. For years this has been an occasional nuisance. At 1.7 million objects, it becomes a permanent condition. SpaceX alone plans to launch over a million satellites by 2028 to power AI data centers. China is building two separate constellations. And the startup Reflect Orbital is proposing 50,000 satellites fitted with giant mirrors to bounce sunlight back to Earth at night — a plan that would brighten the entire night sky by a factor of four, making each satellite as bright as Venus and rendering nearly every image from Chile's Vera C. Rubin Observatory, the largest camera ever built, scientifically useless.
The damage would not stop at frustrated scientists. Ecosystems dependent on darkness would be destabilized. The sheer density of objects in orbit raises the specter of Kessler syndrome — a chain reaction of collisions producing debris clouds that could render entire orbital zones unusable for decades. And the environmental cost of launching nearly two million objects into space has barely entered the public conversation.
The ESO, alongside the Royal Astronomical Society and the International Astronomical Union, has submitted a formal recommendation to the US Federal Communications Commission: cap satellites in orbit at 100,000 and require all of them to be dimmed below naked-eye visibility. The FCC must now decide whether to approve the pending applications from Reflect Orbital and SpaceX. Whether regulators treat this as the existential question astronomers say it is remains, for now, unanswered.
Somewhere above Earth right now, roughly 14,000 satellites are circling the planet. Most of them arrived in the last few years, part of Elon Musk's Starlink network and other commercial ventures. But that number is about to look quaint. Companies are preparing to launch 1.7 million more satellites into orbit over the coming years—a deployment so massive that it will fundamentally alter what astronomers can see when they point their instruments at the sky.
The European Southern Observatory published research this week documenting what happens when you add that many bright objects to the heavens. The answer is blunt: it breaks astronomy. Olivier Hainaut, the astronomer who led the study, explained the mechanics simply. When a satellite crosses the field of view of a telescope, it leaves a bright streak across the image, erasing whatever celestial object was behind it. For years now, this has been an occasional annoyance. But the scale of what's coming changes everything. "If we go from 14,000 to 1.7 million, we are really going to have problems," Hainaut said.
The threat comes from multiple directions. SpaceX alone plans to launch more than a million satellites by 2028, ostensibly to power artificial intelligence data centers. The startup E-Space has its own "Cinnamon" constellation in the works. China is building two separate systems called CTC-1 and CTC-2. And then there is Reflect Orbital, a US company proposing something particularly audacious: 50,000 enormous satellites equipped with giant mirrors designed to bounce sunlight back down to Earth at night, essentially creating artificial illumination from space.
The Reflect Orbital plan alone would brighten the entire night sky by a factor of four. Even when the mirrors aren't pointed at an observer, the light they scatter would make each satellite as bright as Venus. The researchers calculated that nearly every image captured by the Vera C. Rubin Observatory in Chile—the largest camera ever built—would become unusable. Whether you're observing from France, the Sahara, or the Andes, the sky would no longer look like the night sky at all. It would resemble the washed-out darkness you see on the outskirts of a major city. In heavily light-polluted urban areas, the satellites would be the only stars visible.
The problem extends far beyond frustrated astronomers. Light pollution of this magnitude disrupts the biological rhythms of humans and animals alike. Ecosystems that depend on darkness would collapse. There are also practical concerns about the sheer number of objects in orbit—the risk that they will collide with each other in a cascade of destruction known as Kessler syndrome, creating debris that could make certain orbital zones unusable for decades. And then there is the environmental cost of launching nearly two million satellites into space.
Hainaut and his colleagues have proposed a solution, though it amounts to a plea. They are calling for a hard cap of 100,000 satellites in orbit, with a requirement that all of them be dimmed to the point of invisibility to the naked eye. The European Southern Observatory, working with the Royal Astronomical Society and the International Astronomical Union, submitted this recommendation to the US Federal Communications Commission, which must now decide whether to approve the Reflect Orbital and SpaceX applications. "For optical astronomy, this is an existential threat," said Betty Kioko, the ESO's institutional affairs officer. The decision rests with the regulators. The question is whether they will treat it that way.
Citações Notáveis
If we go from 14,000 to 1.7 million, we are really going to have problems.— Olivier Hainaut, ESO astronomer leading the study
For optical astronomy, this is an existential threat, and we hope that the regulators will share that view.— Betty Kioko, ESO institutional affairs officer
A Conversa do Hearth Outra perspectiva sobre a história
Why does it matter if satellites are bright? Can't astronomers just adjust their equipment?
A bright satellite crossing your field of view is like someone turning on a flashlight in front of your eyes while you're trying to read. You can't adjust your way out of it. The light simply erases what's behind it. With 1.7 million satellites, you're not dealing with occasional interruptions—you're dealing with a fundamentally altered sky.
But these satellites serve a purpose, right? Internet access, AI infrastructure. Isn't that valuable?
Absolutely. The connectivity and computing power they promise is real and significant. The tension here is genuine. But the research shows we're not weighing the tradeoffs carefully. We're allowing the deployment to happen without understanding the cost.
What's the difference between Starlink and this Reflect Orbital company?
Starlink satellites are already up there and they're a problem, but they're relatively small and not designed to be reflective. Reflect Orbital wants to launch 50,000 massive mirrors into space specifically to bounce sunlight around. It's a different order of magnitude of brightness.
Is there any way to make this work? Can you dim the satellites?
That's exactly what the researchers are proposing—a 100,000-satellite limit with mandatory dimming technology. It's a compromise. But it requires regulators to actually enforce it, and right now, companies are moving faster than the rules can keep up.
Who decides this?
The US Federal Communications Commission. They're reviewing the applications from SpaceX and Reflect Orbital right now. The ESO and other astronomical organizations have submitted their research as evidence, but ultimately it's a regulatory decision, not a scientific one.
What happens if they approve it anyway?
Then we lose the night sky as a scientific resource. The largest telescopes on Earth become partially blind. And we lose something else too—the darkness itself, which ecosystems and human biology depend on in ways we're still understanding.