INTERACTIVE

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Number crunching

Thank you for all you are doing for a great and long-lived magazine. In July’s book reviews section, I was interested to read that author Antonio Padilla calculates the biggest number in the Universe to be 10 (review of page 94). In my forthcoming book on the history of Greek astronomy, I summarise Archimedes’s calculation of the size of the heliocentric Universe, and follow up by looking at this brilliant mathematician’s zest for exploring even larger numbers. Not content with numbers restricted to the size of the Universe, Archimedes continued to construct a perfectly logical counting structure that soared way beyond human imagining until he finally decided to call a halt when (converted from Greek to our numeration)! A listing of Archimedes’s values for interplanetary distances has come down to us, but unfortunately through a garbled secondary source.