Elon Musk’s SpaceX is sending “Starlink” satellites into orbit so frequently that “it will likely end ground-based astronomy as we know it,” due to the fact that they prevent scientists from viewing the night sky from earth-based observatories uninterrupted, a prominent astrophysicist has warned.
Writing in Forbes, theoretical astrophysicist Ethan Siegel warns that Musk — a hero to environmentalists due to his line of electric cars — risks polluting the night sky to such an extent that ground-based observatories that cost the scientific community hundreds of millions of dollars to build could be rendered effectively useless.
Musk’s plan is to build a “mega-constellation” of Starlink satellites numbering 42,000. But Siegel writes that even though just 122 of these have been launched, it is having a massive impact on the field of astronomy.
From the darkest skies you can find on Earth, approximately 9,000 stars are visible to human eyes: down to a visual magnitude of +6.5, the limit of human vision. Yet the first 122 satellites launched by Starlink are not only brighter than the majority of these stars, they move quickly throughout the sky, leaving trails that pollute astronomers’ data.
If these satellites were either faint, few in number, or slowly moving, this would be only a mild problem. If you’re only observing a narrow region of the sky, you’d simply reject any exposure frames (or even just the pixels from them) where the offending objects streak across the sky. But with large numbers of bright, rapidly moving satellites, particularly if you’re searching for changes from frame-to-frame (like many current and future observatories are designed to do), you have to throw out any exposure frame with these artifacts in them.
Previous constellations of Satellites, writes Siegel, “proceeded in clearly defined and predictable orbits, were few in number, and only flared brightly when their orientation reflected sunlight in a particular manner.”
According to Siegel, Musk’s satellites do none of these things. He cites an incident in which a Starlink satellite almost collided with a scientific satellite used for earth observation, an incident SpaceX blamed on a “bug.”
SpaceX and Musk have issued statements saying its satellites will not significantly impact astronomy, that it will reduce the albedo (brightness) of its satellites, and that it will adjust orientation on demand for astronomical experiments.
“All of these statements are not yet true as of November 20, 2019,” writes Siegel.
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Allum Bokhari is the senior technology correspondent at Breitbart News.