For the past decade, cosmologists have been puzzled by a discrepancy between two methods used to measure the universe's rate of expansion, known as the Hubble tension. This discrepancy points to two possible explanations: either the measurements are flawed, or our understanding of the universe itself is incomplete. Hopes were high that observations from the James Webb Space Telescope would clarify the issue, but results published last week have only deepened the confusion. To explore why the universe's expansion rate remains elusive and what might be required to resolve this mystery, Madeleine Finlay speaks with Catherine Heymans, the Astronomer Royal for Scotland and a professor of astrophysics at the University of Edinburgh.

Disclaimer: This podcast is taken from The Guardian.