The Trial of Galileo
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Galileo Team #1
Discuss how Galileo's claims about Copernicanism are well justified by astronomical observations (and thus that the 1616 decision declaring Copernicanism heretical is unjustified). Each person will focus on profiling the significance of one set of evidence:

  • moon surface, nova and sunspots
  • the moons of Jupiter and planetary retrograde
  • the phases and size of Venus
  • the motion of sunspots and the annual motion of the sun
For further depth, you may also discuss:
  • the role of the telescope and its reliability
  • the validation of observations by astronomers within the Church, and/or
  • potentially favorable evidence that Galileo rejects as inadequate (for example, see investigations on Gilbert in Day 3).
  • Galileo's explanation for the lack of observed stellar parallax (a potential objection)


    For the first three topics, read:
  • [essential] Galileo's earlier Starry Messenger (Siderius Nuncius) (1610)
  • relevant sections in the Dialogue (use the index and/or word-search!)
  • For background, Crowe, Theories of the World from Antiquity to the Copernican Revolution.
  • For background, Swerdlow's Chap. 7 in Machamer (1998).
  • For background, sections in Fantoli, Galileo: For Copernicanism and the Church.

    For the claims about sunspots, review:
  • Galileo's Dialogue, Day 3 (esp. section starting on p. 400)
  • Fantoli, Galileo: For Copernicanism and the Church (on Day 3).