ESO warns Musk’s mega-satellites could blind telescopes

ESO warns – The European Southern Observatory says the surge in Starlink satellites is already worsening ground-based stargazing and could intensify sharply as Elon Musk pushes plans for up to a million “orbital data centers.” In a new report, ESO proposes limiting “faint

When you point one of Earth’s biggest telescopes at the sky, you’re trying to see through darkness. Lately, the interruptions have been getting brighter—and the European Southern Observatory says the next wave could be outright blinding.

The ESO. an intergovernmental agency that operates some of the world’s most powerful space telescopes. warns that further clogging of the night sky could carry “devastating consequences” for space study on Earth. Its concern includes Elon Musk’s vision of building a one million satellite network of “orbital data centers” powered by endless beams of solar energy.

In a new report. the ESO says the number of satellites orbiting Earth has “skyrocketed” since Musk began flinging satellites into low Earth orbit in 2019. By last month, there were roughly 10,400 satellites in orbit from Starlink, a subsidiary of SpaceX. Before 2022, ESO says, just 14,450 satellites had been launched into space ever across human history.

Olivier Hainaut, the ESO Directorate of Operations, describes what that looks like from the ground: “Until now we have managed, but it’s getting worse.” For anyone observing space from the ground, he explains, satellites scatter light unpredictably and interfere with the imaging process.

The proposal that alarms astronomers centers on scale. The ESO is proposing a limit of 100. 000 “faint satellites. below naked eye visibility” as a ceiling meant to reduce the harm from so many shiny objects in lower Earth orbit. The group’s researchers ran simulations projecting how a flood of Starlink satellites could disrupt the world’s most powerful space telescopes—and the results. the ESO says. were not reassuring.

For Europe’s flagship Very Large Telescope (VLT) in Chile’s Paranal Observatory. the ESO estimates the telescope’s field of view would be diminished by 28%. even in the best of circumstances where satellites are not visible to the naked eye. If satellites glow even a little brighter. ESO says they would begin causing problems for other telescopes. including the Vera C. Rubin Observatory, which would be “essentially blind for several hours every night.”.

Hainaut puts the mechanism in plain terms. “Satellites, illuminated by the Sun, are much brighter than distant galaxies,” he said. “When a satellite crosses what we observe, it makes a bright streak on our image, zapping whatever is behind it.”

The stakes are personal for a field that has spent years designing instruments to pull faint signals from a sky that’s as clean as possible. Telescopes like the VLT are built from many millions of dollars of investment and many years of scientific research and planning. set up in some of the planet’s highest. driest places to study distant phenomena. In that context, the ESO says the problem of light pollution becomes even more vexing.

The ESO’s report distinguishes two kinds of satellite-driven haze. Satellites show up in images as unwanted streaks, but they also create light that brightens the night sky broadly. “Satellites too faint to be seen directly produce a veil of ‘diffuse’ light. while light from brighter satellites is ‘scattered’ in all directions as it passes through the atmosphere. ” the ESO noted. Both diffuse light and scattered light, the report says, are major problems for scientists studying the night sky.

That concern comes as Starlink’s broader push to scale up grows. The ESO says light pollution from satellites has already given the night sky an unwanted glow-up, and that Starlink’s plans to expand exponentially have astronomers even more worried.

Musk. in a blog post announcing plans for the “extraterrestrial data centers. ” cheered the idea of limitless “compute. ” writing: “It’s always sunny in space!” In response to complaints. SpaceX says it is working to make its satellites dimmer to minimize light pollution. The company points to the source of the glow: sunlight bouncing off a satellite’s chassis or solar array.

Still, the ESO’s report argues that scientific and environmental concerns have not been enough to slow the pace of deployment.

Musk has sounded unconcerned about crowding in space. In a video posted in June. he said: “There’s a lot of space up there. and so even when you’re talking thousands. or even. you know. up to a million satellites. you got plenty of room to move around up there.” He added: “Space is really big. so it’s not like space is going to get crowded.”.

Europe’s astronomical research experts disagree. In its report. ESO says one million space-based data center satellites floating in lower Earth orbit would have “drastic consequences” for the field of astronomy. The ESO also raises concern about plans by aerospace company Reflect Orbital to launch energy-generating mirrors in space.

Hainaut frames the issue as more than a technical inconvenience. “Low Earth orbit is a celestial seashore that provides immense value to modern life. from global connectivity to our clear access to the Universe. ” he said. “However. we must manage the footprint of mega-constellations — from the light pollution affecting astronomy to the atmospheric effects of satellite re-entry — to ensure this resource remains pristine and accessible for future generations.”.

For now. ESO’s simulations and proposed ceiling put a hard number on the debate: 100. 000 “faint satellites. below naked eye visibility.” Behind that figure is an insistence that astronomical discovery—dependent on the darkest possible sky—cannot be treated as an endlessly expandable casualty of new infrastructure.

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