Aliens are back on the radar after a US Congressional hearing in the summer that featured former intelligence officer, David Grusch. The US Air Force veteran was once part of a task force created to look into what used to be called UFOs. Mr Grusch gave evidence that caused a sensation in America, claiming that the US military had, for decades, been in possession of crashed UFOs and 'non-human biologics'.

His shocking claims were evidence that, whatever their accuracy, both created and reflected a growing and serious debate - from astrophysicists and astrobiologists to policymakers about what if anything, is out there. Anything alive and anything civilised.

So, as 2023 turns into 2024, what is the state of our understanding about whether or not we are alone in space? David Aaronovitch explores the history of UFOs stretching back to the 1940s and discusses whether intelligent life exists beyond Earth.

David Aaronovitch talks to: Dr Maggie Aderin-Pocock, British space scientist and science educator Garrett Graff, Journalist and historian. Author of ‘UFO: The Inside Story of the U.S. Government's Search for Alien Life Here ― and Out There’. Avi Loeb, Astrophysicist and Baird Professor of Science at Harvard University Monica Grady, Professor of Planetary and Space Science at the Open University.

Presenter: David Aaronovitch Producer: Sally Abrahams Sound: James Beard and Neil Churchill Editor: Richard Vadon

Archive Credits: Congressional Hearing on Unidentified Aerial Phenomena, 26 July 2023 courtesy of C-Span