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Melvyn Bragg and his guests discuss comets, the 'dirty snowballs' of the Solar System. In the early 18th century the Astronomer Royal Sir Edmond Halley compiled a list of appearances of comets, bright objects like stars with long tails which are occasionally visible in the night sky. He concluded that many of these apparitions were in fact the same comet, which returns to our skies around every 75 years, and whose reappearance he correctly predicted. Halley's Comet is today the best known example of a comet, a body of ice and dust which orbits the Sun. Since they contain materials from the time when the Solar System was formed, comets are regarded by scientists as frozen time capsules, with the potential to reveal important information about the early history of our planet and others.


Monica Grady
Professor of Planetary and Space Sciences at the Open University

Paul Murdin
Senior Fellow at the Institute of Astronomy at the University of Cambridge

Don Pollacco
Professor of Astronomy at the University of Warwick

Producer: Thomas Morris.

Release date:

Available now

43 minutes

Last on

Thu 17 Jan 2013 21:30


Professor Monica Grady at the Open University


Professor Don Pollacco at the University of Warwick


Institute of Astronomy, University of Cambridge


New Proof That Comets Watered the Earth - Time


Comet - Wikipedia





John Brandt and Robert Chapman, Introduction to Comets (Cambridge University Press, 2004)


David H. Levy, Comets: Creators and Destroyers (Simon & Schuster, 1998)


Roberta Olson, Fire and Ice: A History of Comets in Art (Walker & Co, 1985)


Sara Schechner, Comets, Popular Culture, and the Birth of Modern Cosmology (Princeton University Press, 1999)


John R. Spencer and Jacqueline Mitton (eds.), The Great Comet Crash: The Collision of Comet Shoemaker-Levy 9 and Jupiter (Cambridge University Press, 1995)


Paul J. Thomas, Roland D. Hicks, Christopher F. Chyba, Christopher P. McKay (eds.), Comets and the Origin and Evolution of Life (Springer, 2006)


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