The Earth’s Core

Melvyn Bragg and his guests discuss the Earth’s Core. The inner core is an extremely dense, solid ball of iron and nickel, the size of the Moon, while the outer core is a flowing liquid, the size of Mars. Thanks to the magnetic fields produced within the core, life on Earth is possible. The magnetosphere protects the Earth from much of the Sun’s radiation and the flow of particles which would otherwise strip away the atmosphere. The precise structure of the core and its properties have been fascinating scientists from the Renaissance. Recent seismographs show the picture is even more complex than we might have imagined, with suggestions that the core is spinning at a different speed and on a different axis from the surface.

Play on BBC Sounds website


  • Stephen Blundell 3 episodes
    Professor of Physics and Fellow of Mansfield College at the University of Oxford
  • Arwen Deuss No other episodes
    Associate Professor in Seismology at Utrecht University
  • Simon Redfern No other episodes
    Professor of Mineral Physics at the University of Cambridge

Reading list

  • Magnetism: A Very Short Introduction
    Stephen J. Blundell (Oxford University Press, 2012) Google Books →
  • Nebulous Earth: A History of Modern Planetary Physics
    Stephen G. Brush (Cambridge University Press, 1996) Google Books →
  • Fundamentals of Geophysics
    William Lowrie (Cambridge University Press, 2007) Google Books →
  • Our Magnetic Earth: The Science of Geomagnetism
    Ronald T. Merrill (University of Chicago Press, 2010) Google Books →
  • The Earth: A Very Short Introduction
    Martin Redfern (Oxford University Press, 2003) Google Books →
  • Physics of the Earth
    Frank D. Stacey and Paul M. Davis (Cambridge University Press, 2008) Google Books →

Related episodes

Programme ID: b05s3gyv

Episode page:

Auto-category: 550 (Earth sciences)