For decades, astronomers wanting to use their high-powered telescopes to peer up into the night sky have had to deal with the problem of so-called ‘light pollution’, mainly from artificial city lights getting in the way of their observations. In recent years, however, a different source of light pollution has become more and more of a problem for them – the fast-growing number of space satellites orbiting the earth. Moreover it’s a problem that will soon get much worse, with companies like SpaceX and Amazon now planning to launch tens of thousands of communication satellites in the coming years. Jonathan talks with physicist and light pollution expert František Kundracik about this growing problem.