Brahmagupta · Mathematics

The Round Earth, Gravity, and the Demon Rahu

Brahmagupta’s astronomy - a spherical earth that draws heavy things toward it, planetary and eclipse computation by geometry - set against his stubborn conservatism: he rejected Aryabhata’s rotating earth and, on scriptural authority, defended the demon Rahu as the cause of eclipses. A study in brilliance bounded by orthodoxy.

What you'll be able to recall

You learned that Brahmagupta’s Brahmasphutasiddhanta is chiefly an astronomy treatise; that he held the earth to be a sphere that draws heavy things toward it (an early attraction idea); that he rejected Aryabhata’s rotating earth; and that, despite computing eclipses geometrically, he defended the demon R…

Leads to Aryabhata.

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