The sky would no longer be clear, resembling instead the suburbs of a city
For as long as humans have looked upward, the night sky has served as both mirror and map — a place where we locate ourselves in time, in space, and in meaning. Now, a convergence of commercial ambition and technological scale threatens to close that window permanently. Researchers at the European Southern Observatory warn that plans to launch 1.7 million satellites would brighten the night sky fourfold, rendering the world's greatest telescopes effectively blind. The question before regulators is not merely technical — it is whether the sky above us belongs to commerce, or to everyone.
- Astronomers are sounding an existential alarm: 1.7 million planned satellites would transform the night sky into something resembling suburban light pollution, making serious observation nearly impossible from anywhere on Earth.
- The Vera C. Rubin Observatory — home to the largest camera ever built — would see almost every image it captures ruined by satellite streaks, a loss that would cripple humanity's ability to study the cosmos.
- Reflect Orbital's proposal to launch 50,000 mirror-equipped satellites is particularly alarming; even when deflected, their scattered light would make each one as bright as Venus, collectively quadrupling sky brightness.
- The damage reaches beyond science — disrupted ecosystems, cascading orbital collisions, and the irreversible environmental cost of launching nearly two million objects into space compound the stakes.
- The European Southern Observatory is pushing for a hard cap of 100,000 satellites with strict brightness limits, while the FCC holds the regulatory power to approve or restrain the constellations now awaiting launch clearance.
Fourteen thousand satellites already cross the night sky — a number that arrived almost without public notice, part of a quiet race to encircle Earth with connectivity and computation. But that figure is only the beginning. Companies have filed plans to launch more than 1.7 million additional satellites, a scale so unprecedented that astronomers are now describing it as an existential threat to ground-based observation.
The European Southern Observatory published research this week laying out what that future would look like. When satellites pass through a telescope's field of view, they leave bright streaks that erase whatever lies behind them. At 1.7 million, the problem is no longer manageable — the sky itself becomes the obstacle. Lead researcher Olivier Hainaut described it plainly: the night sky would come to resemble the washed-out haze that hangs over a city's suburbs, unreliable for any serious science.
The sources of this swarm are varied. SpaceX plans to launch over a million satellites by 2028 to power AI data centers. China is developing two large constellations of its own. A startup called E-Space is planning hundreds of thousands more. Most alarming is Reflect Orbital, which proposes 50,000 mirror-equipped satellites designed to bounce sunlight back to Earth at night — satellites so reflective that even when deflected, each would appear as bright as Venus. Together, they would quadruple the brightness of the night sky.
The Vera C. Rubin Observatory in Chile, housing the largest camera ever built, would see nearly every image it captures rendered unusable. The effect would be global — identical whether observing from France, the Sahara, or the Andes. In cities, satellites would become the only visible lights in the sky.
The consequences extend beyond astronomy. Light pollution disrupts the biological rhythms of humans and wildlife. The environmental cost of launching two million objects is enormous. And scientists warn of Kessler syndrome — a cascade of collisions that could make entire orbital zones permanently unusable.
The European Southern Observatory is calling for a hard cap of 100,000 satellites, each dim enough to be invisible to the naked eye. Reflect Orbital says it will keep mirrors off by default and avoid pointing light toward observatories. Both SpaceX and Reflect Orbital await FCC approval — and the agency must now decide whether the sky above us is a commercial resource, or something that belongs to all of us.
Somewhere above Earth right now, fourteen thousand satellites are already crossing the night sky. Most of them arrived in the last few years, part of a rush to ring the planet with internet-beaming machines and data-processing mirrors. But that number is just the opening act. Companies have announced plans to launch more than 1.7 million additional satellites into orbit—a swarm so vast that astronomers are now calling it an existential threat to their ability to see the universe at all.
The European Southern Observatory released a study this week calculating what that future would look like. The findings are stark. When satellites cross through a telescope's field of view, they leave bright streaks that erase whatever lies behind them. For now, with fourteen thousand satellites in play, the problem is manageable. But at 1.7 million, the night sky itself becomes the obstacle. Olivier Hainaut, the astronomer who led the research, put it plainly: the sky would stop being clear. Instead, it would resemble the perpetually hazy dome that hangs over a city's suburbs—washed out, dim, unreliable for serious observation.
The threat comes from multiple directions. SpaceX has announced plans to launch more than a million satellites by 2028, designed to power artificial intelligence data centers rather than provide internet service. The Chinese government is developing two massive constellations of its own. A startup called E-Space is planning hundreds of thousands more. But perhaps the most alarming proposal comes from Reflect Orbital, which wants to send fifty thousand enormous satellites into orbit, each equipped with giant mirrors designed to bounce sunlight back down to Earth at night. Even when those mirrors are pointed away from an observer, the light they scatter would make each satellite as bright as Venus. All fifty thousand of them together would quadruple the brightness of the night sky.
The Vera C. Rubin Observatory in Chile houses the largest camera ever built. Researchers determined that almost every image it captures would become unusable if these satellite constellations launch as planned. The effect would be global and indiscriminate. Whether you were observing from France, the Sahara Desert, or Chile itself, the result would be the same: a sky so polluted with artificial light that in cities, the satellites would be the only stars visible at all.
The problem extends far beyond astronomy. Light pollution disrupts the biological rhythms of humans and animals alike, interfering with ecosystems that evolved under the rhythm of actual darkness. There is also the sheer environmental cost of launching nearly two million objects into space, and the growing risk of what scientists call Kessler syndrome—a cascade of collisions between satellites and debris that could render entire orbital zones unusable.
The European Southern Observatory is calling for a hard cap: no more than one hundred thousand satellites in orbit at any time, and those must be dim enough to be invisible to the naked eye. Reflect Orbital has responded by saying it is commissioning independent research and will keep its mirrors off by default, systematically avoiding pointing light toward observatories. SpaceX and Reflect Orbital are both awaiting approval from the U.S. Federal Communications Commission. The decision now rests with regulators who must weigh the commercial interests of the companies against the interests of astronomers, ecosystems, and humanity's ability to see the night sky as anything other than a light show of our own making.
Citações Notáveis
If we go from 14,000 to 1.7 million, we are really going to have problems— Olivier Hainaut, ESO astronomer
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 this matter so much to astronomers right now, when they've always had to deal with light pollution from cities?
Scale. We've gone from thousands of satellites to fourteen thousand in just a few years. The proposals on the table would add another 1.7 million. That's not an incremental problem—it's a categorical shift. The night sky stops being something you can work around and becomes something that's fundamentally altered.
But couldn't telescopes just be moved to darker places, or improved to filter out the light?
Some could be, but not all. The Vera Rubin Observatory cost hundreds of millions of dollars and took decades to build. You can't just relocate it. And there's no filter that makes a bright streak across your image disappear—the satellite is literally blocking your view of whatever's behind it.
What about Reflect Orbital's argument that they'll keep the mirrors off most of the time?
Even when the mirrors are off, the satellites themselves would be as bright as Venus just from scattered light. And that's assuming perfect compliance with a voluntary agreement. Once fifty thousand objects are in orbit, you're dependent on a company maintaining a system indefinitely.
Is this really an existential threat, or is that hyperbole?
For optical astronomy—ground-based telescopes looking at the visible universe—yes. If you can't take usable images, the science stops. That's not metaphorical. It's the end of a capability humanity has had for four hundred years.
Who actually decides whether these satellites launch?
The FCC in the United States. Both SpaceX and Reflect Orbital are waiting for approval. The European Southern Observatory submitted its research as part of their response to those applications. So the decision is imminent, and it's regulatory, not scientific.
What would actually need to happen to prevent this?
A hard limit on the number of satellites allowed in orbit, and strict brightness requirements. The ESO is calling for a maximum of one hundred thousand, with satellites dim enough to be invisible to the naked eye. Whether regulators will enforce that is the open question.