Giacomo Filippo Maraldi was a French-Italian astronomer, mathematician, and geodesist. He worked most of his life at the Paris Observatory.
Background
Giacomo Filippo Maraldi was born on August 21, 1665, in Perinaldo, Liguria, Italy of Giovanni Francesco Maraldi di Oneglia and Angela Cassini, sister of Giovanni Domenico Cassini (also known as Cassini I), who had helped to found the Paris observatory.
Education
There is no information on what kind of education did Giacomo Filippo Maraldi receive except that he studied classics and of mathematics, but based on his social status it can be guessed that he received a good one for his time and was partially taught by his maternal uncle Giovanni Domenico Cassini.
Career
Giacomo Filippo Maraldi was called to Paris in 1687 by his uncle Cassini I. He soon became his devoted collaborator, and eventually assisted his son, Cassini II, as well. He participated in the observatory’s work for thirty years. He lived with other astronomers who filled the Observatory’s rooms. Giacomo Filippo Maraldi is also known as Jacques Phillipe Maraldi and, to distinguish him from other Maraldi astronomers, is referred to as Maraldi I.
Upon arriving in France, Maraldi I started producing a new catalog of the fixed stars, a project he continued throughout his career. This important work, which he almost succeeded in completing, unfortunately was never published, with the exception of certain stellar positions utilized by Deslisle, Manfredi, and Brouckner. An active participant in the daily observations made at the observatory, Maraldi I left behind several unpublished journals. He published many notes in the annual volumes of the Histoire de l’Académie royale des sciences concerning the planets, their satellites, eclipses, and variable stars, as well as some more theoretical memoirs. In one of the latter, “Considérations sur la seconde inégalité du mouvement des satellites de Jupiter et l’hypothése du mouvement successif de la lumiére”.
In 1700 and 1701 Maraldi I participated with Cassini II, J. M. de Chazelles and Pierre Couplet in the operations directed by Cassini I to extend the meridian of Paris to France’s southern frontier. He then spent two years in Rome, making various astronomical observations - including one on the zodiacal light - and sharing on the determination and construction of the meridian of the Church of the Carthusians. He returned to Paris in 1703 and resumed his observations, interrupting them for several months in 1718, to take part, with Cassini II and G. de La Hire, in the extension as far as Dunkirk of the Paris - Amiens meridian measured by Jean Picard in 1670.
In 1726 Maraldi brought his nephew Giovanni Domenico (Maraldi II), the son of his brother Gian Domenico and Angela Francesca Mavena, to Paris.
Giacomo Filippo is mainly known for his work on the planet, Mars, though he also worked on observations of the stars. He made careful observations of Mars at every opposition with particularly good results from the perihelic oppositions of 1704 and 1719. He determined the rotation period of Mars noting that the same region returns to be visible after 36 rotations of Mars (or 37 rotations of Earth), thus calculating a rotation period of about 24h 40m. He discovered banded structures on the surface of Mars which are actually the Mare Sirenum and Mare Tyrrhenum abledo features. In addition he observed an hourglass sea, Syrtis Major, and studied the properties and changes of the polar caps on Mars.
On the 24th July 1721, Giacomo Filippo and Jacques Cassini accompanied two of the principal astronomers from the Observatoire to observe a partial eclipse of the sun. Louis XV took a keen interest in the event and went himself to the Observatoire where the chart of the moon was explained to him. In 1726, with the death of Guillaume Delisle, the King conferred on Giacomo Filippo the title of First Geographer.
Achievements
Views
Giacomo Filippo Maraldi defended the point of view of Cassini I, opposing the hypothesis of the finite velocity of light, conceived by Ole Römer to account for certain irregularities in the movement of Jupiter’s satellites.
Giacomo Filippo Maraldi is also known for his work in mathematics. In 1712 he stated that the internal angle of a dodecahedron, which came to be known as the Maraldi angle, was 109º 28´.
Membership
Academy of Sciences
,
France
Connections
There is no information on whether Giacomo Filippo Maraldi was ever married or had any children.