This episode of the Physics World Weekly podcast looks at how studying the deep-ocean floor could help scientists who are scanning the cosmos for signs of intelligent life. Our guest is Pablo Sobron of the SETI Institute and Impossible Sensing, who explains how the Laser Divebot spectrometer is shedding light on the biochemistry of the seafloor – and what this information tells us about the biodiversity of the oceans and how life could emerge elsewhere in the universe.

Also in this episode, Aarhus University’s Jeffrey Hangst talks about the first ever observation of freefalling antimatter – which was made by Hangst and colleagues using the ALPHA-g experiment at CERN. While the experiment confirmed that antimatter falls down rather than up, there is still a tantalizing possibility that future experiments could identify a small difference in how matter and antimatter respond to gravity.