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johncarlosbaez's profile
John Carlos Baez
John Carlos Baez
John Carlos Baez
@johncarlosbaez

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John Carlos Baez

@johncarlosbaez

I do math, physics, and applied category theory at U. C. Riverside.

Riverside, CA
math.ucr.edu/home/baez/
Joined September 2016

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    John Carlos Baez‏ @johncarlosbaez 22 Aug 2019

    The Antikythera mechanism, found undersea in the Mediterranean, dates to roughly 60-200 BC. It's a full-fledged analogue computer! It had at least 30 gears and could predict eclipses, even modelling changes in the Moon's speed as it orbits the Earth. (1/n)pic.twitter.com/7m8N1oA0Kx

    10:37 PM - 22 Aug 2019
    • 192 Retweets
    • 558 Likes
    • Carlos Gambino Panagiotis Xipteras Achmet Tachsin abhigyan ray Violeta Calleja Solanas Lava Chicken JSlower That's me done Nell
    15 replies 192 retweets 558 likes
      1. New conversation
      2. John Carlos Baez‏ @johncarlosbaez 22 Aug 2019

        What Greek knowledge was lost during the Roman takeover? We'll never really know. They killed Archimedes and plundered Syracuse in 212 BC. Ptolemy the Fat - "Physcon" - put an end to science in Alexandria in 154 BC with brutal persecutions. (2/n)pic.twitter.com/Fq6wZIt7qI

        3 replies 23 retweets 66 likes
        Show this thread
      3. John Carlos Baez‏ @johncarlosbaez 22 Aug 2019

        The Library of Alexandria was not destroyed once and for all in a single huge fire. The 6th head librarian, Aristarchus of Samothrace, fled when Physcon took over. The library was indeed set on fire in the civil war of 48 BC. But it seems to have lasted until 260 AD. (3/n)pic.twitter.com/ToWpmrcDDE

        1 reply 13 retweets 56 likes
        Show this thread
      4. John Carlos Baez‏ @johncarlosbaez 22 Aug 2019

        When the Romans took over, they dumbed things down. In "The Forgotten Revolution", Lucio Rosso explains the evil effects of this. For example: we have the first 4 books by Apollonius on conic sections - the more elementary ones - but the other 3 have been lost. (4/n)pic.twitter.com/eaauY64zsS

        1 reply 16 retweets 63 likes
        Show this thread
      5. John Carlos Baez‏ @johncarlosbaez 22 Aug 2019

        Archimedes figured out the volume and surface area of a sphere, and the area under a parabola, in a letter to Eratosthenes. He used modern ideas like "infinitesimals"! But this letter was written over by Christian monks, and only rediscovered in 1906. (4/n)pic.twitter.com/LgSTAbYREU

        1 reply 25 retweets 97 likes
        Show this thread
      6. John Carlos Baez‏ @johncarlosbaez 22 Aug 2019

        So we'll never know the full heights of Greek science and mathematics. If we hadn't found one example of an analogue computer in a shipwreck in 1902, we wouldn't have guessed they could make those! And we shouldn't count on our current knowledge lasting forever, either. (5/n)

        2 replies 17 retweets 96 likes
        Show this thread
      7. John Carlos Baez‏ @johncarlosbaez 22 Aug 2019

        For more, read these: https://en.wikipedia.org/wiki/Antikythera_mechanism … https://en.wikipedia.org/wiki/Archimedes_Palimpsest … and especially Lucio Rosso's book "The Forgotten Revolution": https://www.springer.com/gp/book/9783540200680 … (6/n, n = 6)https://youtu.be/VqtEppZmjfw?t=12 …

        5 replies 11 retweets 45 likes
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      8. John Carlos Baez‏ @johncarlosbaez 23 Aug 2019

        Here's a better source of info on Lucio Russo's book "The Forgotten Revolution": http://www.math.purdue.edu/~eremenko/russo.html … The first chapter and great reviews by my friend the physicist @carlorovelli and my analysis teacher the mathematician Sandro Graffi!

        6 replies 8 retweets 44 likes
        Show this thread
      9. End of conversation
      1. New conversation
      2. theHigherGeometer‏ @HigherGeometer 22 Aug 2019
        Replying to @johncarlosbaez

        60-200BC?

        1 reply 0 retweets 2 likes
      3. John Carlos Baez‏ @johncarlosbaez 22 Aug 2019
        Replying to @HigherGeometer

        Whatever. 200-60 BC.

        2 replies 0 retweets 11 likes
      4. 2 more replies
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      2. John Carlos Baez‏ @johncarlosbaez 24 Aug 2019

        How do we know *what*?

        0 replies 0 retweets 0 likes
      3. 2 more replies

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