The Economist Menu Weekly edition Search Sign in International Nov 27th 2021 edition Whose sky is it anyway? Vast satellite constellations are alarming astronomers They get in the way of the cosmos Nov 25th 2021 O n may 24th 2019 a Falcon 9 rocket built by SpaceX launched 60 communication satellites into a low orbit around the Earth. That evening they appeared as a string of sunlit dots moving across the sky, many of them as bright as the brightest stars, a source of passing wonder and mystery to casual observers—and a portent of doom to astronomers. “There were all these panic messages,” remembers Olivier Hainaut of the European Southern Observatory (eso): “‘Oh my God, it's the end, it's the end of astronomy as we know it!’” Jonathan McDowell, an astronomer at the Harvard-Smithsonian Centre for Astrophysics, says he was “gobsmacked” by how bright the satellites were. “I did some quick mental arithmetic and realised that thousands of satellites that bright would be a substantial fraction of the visible things in the sky…I felt an increasingly large pit in my stomach.” SIMPLY SCIENCE Curious about the world? Enjoy a weekly fix of our mind-expanding science coverage Delivered to you every week Sign up More from International After COP26 The Glasgow summit left a huge hole in the world’s plans to curb climate change Into waters uncharted Was COP26 in Glasgow a success? Death on demand In the West, assisted dying is rapidly becoming legal and accepted Subscribe Group subscriptions Reuse our content Help and contact us Keep updated Facebook Instagram Twitter LinkedIn YouTube RSS Published since September 1843 to take part in “a severe contest between intelligence, which presses forward, and an unworthy, timid ignorance obstructing our progress.” The Economist About Advertise Press centre Store The Economist Group The Economist Group Economist Intelligence Economist Impact Economist Events Working Here Which MBA? GMAT Tutor GRE Tutor Executive Jobs Executive Education Navigator Executive Education: The New Global Order Executive Education: Business Writing Terms of Use Privacy Cookie Policy Manage Cookies Accessibility Modern Slavery Statement Do Not Sell My Personal Information Copyright © The Economist Newspaper Limited 2021. All rights reserved.