Person: Riccioli, Giovanni Battista
Giovanni Battista Riccioli was an Italian astronomer and a Jesuit priest. He is known for his experiments with pendulums and falling bodies.
Mathematical Profile (Excerpt):
- Riccioli entered the Jesuit Order on 6 October 1614, when he was 16 years of age.
- The Jesuits ran three educational establishments in Parma, the university, a college for educating the sons of the nobility, and a Jesuit College, established around 1600, which Riccioli attended.
- Riccioli spent eight years at the Jesuit College at Parma.
- Here he was taught by Giuseppe Biancani (1565-1624) and Riccioli later offered his thanks to Biancani who had a strong influence on him.
- Riccioli became fascinated with astronomy and devoted his research activities to this topic although he also engaged in work on related topics.
- Riccioli moved to Mantua for the year 1633-34, but he was able to work with Cabeo at Ferrara on further studies with the pendulum and falling bodies in 1634.
- There has been much discussion between historians as to exactly what Riccioli believed, in particular whether he believed in the theories propounded by Galileo despite his writings in which he opposed them.
- It seems likely that one reason for the lack of clarity is that Riccioli's views became more strongly opposed to those of Galileo as the years went by.
- If we look at the work on falling bodies which he undertook in 1634, then we only have Riccioli's writing about this in 1651 by which time his views may have to some extent changed.
- During this year in Parma, Riccioli taught Francesco Maria Grimaldi and after the two moved to Bologna in 1636 they did much work together.
- Grimaldi was 20 years younger than Riccioli and, throughout their work together, publications appeared under Riccioli's name but he gave full credit to Grimaldi who, as the younger man, took on the hardest parts of the experimental work.
- First, Grimaldi and Riccioli calibrated a pendulum by getting it to swing for 24 hours (measured by the star Arcturus crossing the meridian line).
- Riccioli was very impressed by Kepler's realisation that the planets moved in elliptical orbits round the sun.
- We have quoted from Almagestum novum (1651) but we have not explained the nature of this large work by Riccioli.
- Book IV, on the moon, contains much material which comes from observations carried out by Grimaldi working under instruction from Riccioli.
- Riccioli cannot only depict perceived relationships between lunar features, but can also tell us 'what the moon is' by means of 'what it is not': it is lunar, not earthly.
- These are scientific arguments, but Riccioli also adds Scriptural arguments.
- The work also includes an argument by Riccioli supporting the decision of the Inquisition against Galileo.
- Another project on which Riccioli was assisted by Grimaldi was a survey, using triangulation, undertaken to determine a meridian line for Bologna.
- In addition to Grimaldi, he was also assisted by Ovidio Montalbini (1601-1672), a professor at Bologna University and the custodian of its science museum, and Giovanni Domenico Cassini, who had been appointed as professor of mathematics at the University of Bologna in 1650 following the death of Bonaventura Cavalieri.
- The project was completed by 1655 and the results published by Riccioli in Geographiae Hydrographiae Reformatae (1661).
- Although a theologian, Riccioli had always felt that his main work and publications should be on astronomy.
- This made Riccioli very angry and one might suppose that this would have made him think again about his wholehearted support for the position the Inquisition took over Galileo.
- It was quite the reverse and, after this, Riccioli went even further in condemning Galileo than the Inquisition had done - his views seem to become more and more hardened against Galileo.
- Riccioli's book defended the doctrine of the Immaculate Conception of Mary against a Dominican who had rejected it.
- However, Riccioli went ahead and published the papal infallibility book with an altered permission to print, thus angering the Dominican inquisitor at Bologna.
- Riccioli published another astronomy book, Astronomia reformata (1665) dedicated to Ferdinand, Duke of Bavaria.
- Among the many discoveries made by Riccioli which we have not yet mentioned, is his first recorded observation a double star, namely the star Mizar in Ursa Major.
- We also did not mention Riccioli's early publication Prododia Bononiensis.
- This two-volume treatise (Volume 1, 1639; Volume 2, 1640) showed the range of Riccioli's expertise for this book was on metrics and Latin prose style.
- Riccioli's character was described by his contemporaries as sanguine, fiery, choleric, melancholic and phlegmatic.
Born 17 April 1598, Ferrara (now Italy). Died 25 June 1671, Bologna (now Italy).
View full biography at MacTutor
Tags relevant for this person:
Astronomy, Origin Italy
Thank you to the contributors under CC BY-SA 4.0! 
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- non-Github:
- @J-J-O'Connor
- @E-F-Robertson
References
Adapted from other CC BY-SA 4.0 Sources:
- O’Connor, John J; Robertson, Edmund F: MacTutor History of Mathematics Archive
