“Is anything in the Universe truly infinite, or is infinity something that only exists in mathematics?”

This momentous question came from father and son duo from Edinburgh Sorley aged 10 and Tom, aged adult. It's a subject so big, that we've devoted two episodes to our never-ending quest to investigate infinity.

The first installment is a story of mathematics, music and murder. We'll find out why the ancient Pythagoreans decided that infinity was evil, and why some infinities are bigger than others.

Featuring the marvellous mathematical minds of Steven Strogatz from the Cornell University and Eugenia Cheng, author of 'Beyond Infinity'.

Presenters: Adam Rutherford, Hannah Fry

Producer: Michelle Martin

First broadcast on BBC Radio 4 in December 2018.