In the 65 years since Sputnik 1 was launched in 1957, the number of artificial satellites in orbit has been increasing. In the last two years, the number of satellites has doubled, largely thanks to the huge “constellations” launched by companies such as SpaceX.

The number of satellites has a detrimental impact on astronomical observations, both with professional telescopes and by amateur astronomers. Dr Meredith Rawls, from University of Washington, is planning observations with the Vera Rubin Observatory, while Professor Andy Lawrence is a Regius Professor at the Royal Observatory Edinburgh. With forecasts indicating up to 100,000 satellites in a matter of years, a 20-fold increase on today’s numbers, there could be serious implications for astronomers around the world.

But what has led to this increase in satellites? Dr Moribah Jah, co-founder and Chief Scientist at Privateer Space, explains why there are so many satellites being launched, and what the risks are both for satellites and down here on Earth. There are proposed solutions, but they require geopolitical collaboration.

Further afield, this month saw the first images of Sagittarius A*, the supermassive black hole at the centre of our galaxy. Edward Gomez discusses the implications of the detection, and what it might tell us about the evolution of galaxies.

00:00 Sagittarius A* black hole image
08:40 Meredith Rawls and Andy Lawrence
28:10 Moribah Jah