The Encyclopædia Britannica quote comes from their 1968, volume 2, in the article Alfonso X, page 645. This comes from a passage about the Alfonsine Tables commissioned by this Spanish king:
"By this time each planet had been provided with from 40 to 60 epicycles to represent after a fashion its complex movement among the stars. Amazed at the difficulty of the project, Alfonso is credited with the remark that had he been present at the Creation he might have given excellent advice."
In "The Book Nobody Read", Owen Gingerich writes that he challenged Encyclopædia Britannica about the number of epicycles. Their response was that the original author of the entry had died and its source couldn't be verified. Gingerich, has also expressed doubts about the quotation attributed to King Alfonso X.
Today, Encyclopedia Brittanica says what I just said: just one deferent and one epicycle for each planet:
https://www.britannica.com/science/celestial-mechanics-physics#ref611346
They still manage to take a dig at the medievals, saying Ptolemy's theory "was adopted as absolute dogma and survived more than 1,000 years until the time of Copernicus."
For the controversy over whether medieval astronomers used lots of epicycles, start here:
https://en.wikipedia.org/wiki/Deferent_and_epicycle#The_number_of_epicycles
and then dig into the sources!
(2/2)
John Carlos Baez /
npub17u…8pd6m
2024-12-14 19:46:47
in reply to nevent1q…vxxt
Author Public Key
npub17u6xav5rjq4d48fpcyy6j05rz2xelp7clnl8ptvpnval9tvmectqp8pd6mPublished at
2024-12-14 19:46:47Event JSON
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"content": "The Encyclopædia Britannica quote comes from their 1968, volume 2, in the article Alfonso X, page 645. This comes from a passage about the Alfonsine Tables commissioned by this Spanish king:\n\n\"By this time each planet had been provided with from 40 to 60 epicycles to represent after a fashion its complex movement among the stars. Amazed at the difficulty of the project, Alfonso is credited with the remark that had he been present at the Creation he might have given excellent advice.\"\n\nIn \"The Book Nobody Read\", Owen Gingerich writes that he challenged Encyclopædia Britannica about the number of epicycles. Their response was that the original author of the entry had died and its source couldn't be verified. Gingerich, has also expressed doubts about the quotation attributed to King Alfonso X.\n\nToday, Encyclopedia Brittanica says what I just said: just one deferent and one epicycle for each planet:\n\nhttps://www.britannica.com/science/celestial-mechanics-physics#ref611346\n\nThey still manage to take a dig at the medievals, saying Ptolemy's theory \"was adopted as absolute dogma and survived more than 1,000 years until the time of Copernicus.\"\n\nFor the controversy over whether medieval astronomers used lots of epicycles, start here:\n\nhttps://en.wikipedia.org/wiki/Deferent_and_epicycle#The_number_of_epicycles\n\nand then dig into the sources!\n\n(2/2)",
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