If ever there was a timeless philosophical question, "What is the ultimate nature of the universe?" must count as one of the most fascinating. Although the Ancients pondered this question and came up with their own answers, contemporary cosmology suggests that most of what they believed was wrong. Yet as our scientific knowledge of the universe expands, some of the greatest mysteries only deepen.

In this eight-episode series, sponsored by a generous grant from the John Templeton Foundation, we invite listeners on a grand philosophical journey through the cosmos, tackling deeply puzzling questions about the nature of the universe, and our knowledge of it.

What is the origin of the universe? What exactly are space and time? Could the laws of physics ever change? Is the universe fine-tuned to support intelligent life? What are dark matter and dark energy? Are we part of a multiverse? How does science make progress in answering these questions? And are there limits to what we can ultimately know about the nature of the cosmos?

Listen to the episodes in this series:


1. The Ancient Cosmos: When the Earth Stood Still with Carlo Rovelli (3/13/16)


2. Why Is There Something Rather Than Nothing? with Jim Holt (4/10/16)


3. The Big Bang: Before and After with Katherine Freese (8/14/16)


4. Energy and Matter: The Dark Side with Priya Natarajan (10/09/16)


5. The Mystery of the Multiverse with George Ellis (10/23/16)


6. The Space-Time Continuum with Tim Maudlin (2/19/17)