Science Weekly: Questioning gravity

Astronomy writer Stuart Clark tackles some of the biggest questions about our universe, including gravity and dark energy. His book The Big Questions: The Universe is out now. We send Heather Christie to the Secret Garden Party in Cambridgeshire, where she encounters a giant colour-reading eyeball and has a session with a sex scientist. Joining the podcast for the "show and tell" news section are environmentguardian.co.uk's James Randerson and science correspondent Ian Sample . We discuss zombie ants , the heartbreaking tale of starvation at a seed bank in Pavlov , how sponges point to life earlier than previously thought and why the moon is shrinking . WARNING: contains explicit sexual language. Follow the podcast on our Science Weekly Twitter feed and receive updates on all breaking science news stories from Guardian Science . Email [email protected] . Join our Facebook group . Listen back through our archive . Subscribe free via iTunes to ensure every episode gets delivered. (Here is the non-iTunes URL feed ).