For thousands of years humans have looked out into the night sky and pondered on the mysteries of the vast cosmos that we find ourselves part of. From Copernicus’ discovery that the Earth revolves around the Sun to Einstein’s revelation that gravity is the result of the curvature of spacetime, we’ve learned much about how the universe operates. But we’re still only scratching the surface. In this episode, we speak to Marcus Chown, an award-winning science writer and broadcaster and long-time contributor to BBC Science Focus. He explains why pinning down the nature of dark matter and dark energy has eluded us for so long, why we can’t get gravity to agree with the three other forces of nature, and discusses the possibility of the existence of multiple universes. Learn more about your ad choices. Visit podcastchoices.com/adchoices