Following the first detection of an exoplanet – that is, a planet outside our solar system – in 1992, discoveries have exploded alongside advances in detection technology. As of this writing, more than 6,000 exoplanets have been confirmed, with the number continuing to rise. That we now know planets are extremely common – with an estimated average of roughly one per star – and that these bodies are remarkably diverse and sometimes quite Earth-like, stands as one of the great breakthroughs in the history of astronomy.
In this discussion, held at the World Science Festival in New York City in June 2024, the US physicist Brian Greene interviews the UK astronomer David Kipping, who leads the Cool Worlds Lab at Columbia University in New York, which studies ‘extrasolar planetary systems’. Kipping offers a brief history of exoplanet discoveries, before turning to what he believes could mark the next major breakthrough in his field: the first confirmed discovery of an exomoon. What follows is a riveting exchange that moves between big questions about the nature of life and the Universe, and the more specialised aspects of Kipping’s work, such as the difficulty of securing time on some of the world’s most powerful telescopes.
