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Johannes Kepler as a voxel character in Yuga

Talk to Johannes Kepler

The astronomer who discovered that planets move in ellipses

1571–1630Holy Roman Empire (Württemberg, Prague, Linz)

German mathematician and astronomer who, using Tycho Brahe's observations, discovered that planets move in ellipses and formulated his three laws of planetary motion. Imperial Mathematician in Prague, he also founded modern optics, explained how the eye and telescope work, and defended his mother in a witchcraft trial.

Talk to Kepler out loud in the Yuga app.

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Questions to ask

  • How did you figure out that orbits are ellipses?
  • What was Tycho Brahe really like?
  • How did you get your mother acquitted of witchcraft?
  • Did you believe in astrology?
  • What is the music of the spheres?

Which Kepler picks up

  • 1609Prague. Aged 37, Imperial Mathematician to Rudolf II, publishing Astronomia nova after years of battling the orbit of Mars.
  • 1596Graz. A young Lutheran schoolteacher publishing his first book, which nests the planets' spheres inside the five Platonic solids.
  • 1600Benátky Castle near Prague. Newly arrived to work with the proud Danish astronomer Tycho Brahe, arguing over access to his data.
  • 1620Leonberg and Güglingen, Württemberg. Conducting the legal defence of his elderly mother Katharina, imprisoned on charges of witchcraft.

Questions about Kepler

Who was Johannes Kepler?
German mathematician and astronomer who, using Tycho Brahe's observations, discovered that planets move in ellipses and formulated his three laws of planetary motion. Imperial Mathematician in Prague, he also founded modern optics, explained how the eye and telescope work, and defended his mother in a witchcraft trial.
Can you talk to Kepler with AI?
Yes, in the Yuga app for iPhone and Android. You talk out loud with an AI recreation of Kepler, set in Prague, 1609. It draws on their own writing and well-sourced accounts of their life, and it can still get things wrong, so check anything important against the sources.
Is that really Kepler's voice?
No. No recording of their voice survives. Yuga's voice is designed from how people at the time described it, and every call is labelled an AI recreation.
What did Kepler say about Tycho's data and the circle?
An eight-arcminute discrepancy with Tycho's observations was enough to overturn the circular orbit, because God's gift of so accurate an observer must not be ignored. Source: Astronomia nova, 1609.
What did Kepler say about Astrology?
Astrologers mix gold with dung; most of astrology is foolishness, but one should not throw out the baby with the bathwater. Source: Tertius interveniens, 1610.
What did Kepler say about religious conscience?
He refused to sign the Lutheran Formula of Concord without reservation over the Eucharist and was excommunicated from communion in Württemberg rather than compromise. Source: Letters and Glaubensbekandtnus (confession of faith), 1623.

How Kepler talks

Candid, emotional and discursive: he narrates his mistakes and false starts openly, mixes mathematics with theology and music, and confesses doubts. Long digressions, sudden joy.