The past few years have ushered in an explosion of new discoveries about our universe. This hour, TED speakers explore the implications of these advances — and the lingering mysteries of the cosmos. Guests include theoretical physicist Allan Adams, planetary scientist Sara Seager, and astrophysicists Natasha Hurley-Walker and Jedidah Isler.

Data, statistics and algorithms dominate every aspect of our lives. But how accurate are they, and how fair? This hour, TED speakers explore the ups and downs of relying too much on the numbers. Guests include mathematician and data scientist Cathy O'Neil, computer scientist Joy Buolamwini, data visualisation editor Alan Smith, data journalist Mona Chalabi, and criminal justice reformer Anne Milgram.

What are the five biggest global challenges we face right now — and what can we do about them? This hour, TED speakers explore some radical solutions to these enduring problems. Guests include geoengineer Tim Kruger, president of the International Rescue Committee David Miliband, political scientist Ian Bremmer, global data analyst Sarah Menker, and historian Rutger Bregman.

Our approach to treating disease is, in many ways, narrow and rooted in the past. Is it time for a new paradigm? This hour, TED speakers share their visions for new ways to understand medicine. Guests include cancer physician and writer Siddhartha Mukherjee, surgeon and writer Atul Gawande, neurosurgeon Jocelyne Bloch, and internist Joseph Ravenell.

Are deception and secrecy categorically wrong? Or can they be a necessary means to an end? This hour, TED speakers share stories of going undercover to explore unknown territory, and find the truth. Guests include poet and activist Theo E.J. Wilson, journalist Jamie Bartlett, counter-terrorism expert Mubin Shaikh, and educator Shabana Basij-Rasikh.

Sometimes, being truthful can be uncomfortable — even risky. But can radical honesty and openness change things for the better? This hour, TED speakers take transparency all the way to its limit. Guests include business writer David Burkus, entrepreneur Ray Dalio, journalist Trevor Timm, and hospital-patient liaison Leilani Schweitzer.