When I was a child in the 1970s, seeing a satellite pass overhead in the night sky was a rare event. Now it is commonplace: sit outside for a few minutes after dark, and you can’t miss them.

Thousands of satellites have been launched into Earth orbit over the past decade or so, with tens of thousands more planned in coming years. Many of these will be in “mega-constellations” such as Starlink, which aim to cover the entire globe.

These bright, shiny satellites are putting at risk our connection to the cosmos, which has been important to humans for countless millennia and has already been greatly diminished by the growth of cities and artificial lighting. They are also posing a problem for astronomers – and hence for our understanding of the universe.

In new research accepted for publication in Astronomy and Astrophysics Letters, we discovered Starlink satellites are also “leaking” radio signals that interfere with radio astronomy. Even in a “radio quiet zone” in outback Western Australia, we found the satellite emissions were far brighter than any natural source in the sky.

A problem for our understanding of the universe

Our team at Curtin University used radio telescopes in Western Australia to examine the radio signals coming from satellites.

We found expected radio transmissions at designated and licensed radio frequencies, used for communication with Earth.

However, we also found signals at unexpected and unintended frequencies.

We found these signals coming from many Starlink satellites. It appears the signals may originate from electronics on board the spacecraft.