More satellites than stars? SpaceX could ruin night sky as we know it, astronomers worry

A SpaceX launch of 60 highly-reflective satellites has focused astronomers’ concerns on the overpopulation of Earth’s orbit, with thousands of broadband-beaming devices due to launch in coming years, threatening celestial views.

While SpaceX didn’t cause the problem – there are already 2,100 active satellites in Earth’s orbit, according to the Satellite Industry Association – the launch this weekend did crystallize it. Footage shot by a Netherlands astronomer showed the 60 satellites far outshining the stars around them as they climbed toward their eventual position at 550km altitude. SpaceX hopes to one day have 12,000 satellites orbiting the planet, beaming all the high-speed internet humanity could ever want – and it is only one of several companies eyeing the satellite internet sector.

“If many of the satellites in these new mega-constellations had that kind of steady brightness, then in 20 years or less, for a good part the night anywhere in the world, the human eye would see more satellites than stars,” Bill Keel, a University of Alabama astronomer, told AFP.

SpaceX CEO Elon Musk argued that bringing super-fast connections to “billions of economically disadvantaged people” was “the greater good” and insisted his satellites would have “0% impact on advancements in astronomy.” Astronomers, he suggested, could simply move their telescopes into space if they had a problem seeing.

While Musk also pledged to investigate reducing the reflectivity of SpaceX’s satellites, visual pollution isn’t the only problem; satellites’ “side emissions” – the radio frequencies that don’t make it down to earth – also stymie astronomers who use electromagnetic waves to study celestial objects like black holes.

Keel wishes Musk – and his competitors – would think of these things before filling earth’s orbit with their products. “It’s not just safeguarding our professional interests but, as far as possible, protecting the night sky for humanity,” he said.

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