Giacomo Filippo Maraldi (21 August 1665 – 1 December 1729) was a French-

Italian Italian(s) may refer to: * Anything of, from, or related to the people of Italy over the centuries ** Italians, an ethnic group or simply a citizen of the Italian Republic or Italian Kingdom ** Italian language, a Romance language *** Regional Ita ...

astronomer An astronomer is a scientist in the field of astronomy who focuses their studies on a specific question or field outside the scope of Earth. They observe astronomical objects such as stars, planets, natural satellite, moons, comets and galaxy, g ...

and

mathematician A mathematician is someone who uses an extensive knowledge of mathematics in their work, typically to solve mathematical problems. Mathematicians are concerned with numbers, data, quantity, structure, space, models, and change. History On ...

. His name is also given as Jacques Philippe Maraldi. Born in

Perinaldo Perinaldo ( lij, Preinoud) is a ''comune'' (municipality) in the Province of Imperia in the Italy, Italian region Liguria, located about southwest of Genoa and about west of Imperia (city), Imperia. It is the birthplace of the 17th-century Itali ...

(modern

Liguria Liguria (; lij, Ligûria ; french: Ligurie) is a Regions of Italy, region of north-western Italy; its Capital city, capital is Genoa. Its territory is crossed by the Alps and the Apennine Mountains, Apennines Mountain chain, mountain range and is ...

) he was the nephew of

Giovanni Cassini Giovanni Domenico Cassini, also known as Jean-Dominique Cassini (8 June 1625 – 14 September 1712) was an Italian (naturalised French) mathematician, astronomer and engineer. Cassini was born in Perinaldo, near Imperia, at that time in the C ...

, and worked most of his life at the

Paris Observatory The Paris Observatory (french: Observatoire de Paris ), a research institution of the Paris Sciences et Lettres University, is the foremost astronomical observatory of France, and one of the largest astronomical centers in the world. Its histor ...

(1687 – 1718). He also is the uncle of Jean-Dominique Maraldi. From 1700 until 1718 he worked on a catalog of

fixed star In astronomy, fixed stars ( la, stellae fixae) is a term to name the full set of glowing points, astronomical objects actually and mainly stars, that appear not to move relative to one another against the darkness of the night sky in the backg ...

s, and from 1672 until 1719 he studied

Mars Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System, only being larger than Mercury (planet), Mercury. In the English language, Mars is named for the Mars (mythology), Roman god of war. Mars is a terr ...

extensively. His most famous astronomical discovery was that the ice caps on Mars are not exactly on the rotational poles of that body. He also recognized (in May 1724) that the

corona Corona (from the Latin for 'crown') most commonly refers to: * Stellar corona, the outer atmosphere of the Sun or another star * Corona (beer), a Mexican beer * Corona, informal term for the coronavirus SARS-CoV-2, which causes the COVID-19 di ...

visible during a

solar eclipse A solar eclipse occurs when the Moon passes between Earth and the Sun, thereby obscuring the view of the Sun from a small part of the Earth, totally or partially. Such an alignment occurs during an eclipse season, approximately every six month ...

belongs to the

Sun The Sun is the star at the center of the Solar System. It is a nearly perfect ball of hot plasma, heated to incandescence by nuclear fusion reactions in its core. The Sun radiates this energy mainly as light, ultraviolet, and infrared radi ...

not to the

Moon The Moon is Earth's only natural satellite. It is the fifth largest satellite in the Solar System and the largest and most massive relative to its parent planet, with a diameter about one-quarter that of Earth (comparable to the width of ...

, and he discovered

R Hydrae R Hydrae, abbreviated R Hya, is a single star in the equatorial constellation of Hydra, about 2.7° to the east of Gamma Hydrae. It is a Mira-type variable that ranges in apparent visual magnitude from 3.5 down to 10.9 over a period ...

as a

variable star A variable star is a star whose brightness as seen from Earth (its apparent magnitude) changes with time. This variation may be caused by a change in emitted light or by something partly blocking the light, so variable stars are classified as ...

. He also helped with the survey based on the

Paris Meridian The Paris meridian is a meridian line running through the Paris Observatory in Paris, France – now longitude 2°20′14.02500″ East. It was a long-standing rival to the Greenwich meridian as the prime meridian of the world. The "Paris merid ...

. In 1723 From p. 140: ''"La lumiere plus grande au milieu des boules plus petites, fait voir qu'elle circule en plus grande abondance & plus facilement autour des petites boules qu'autour des grandes."'' (More light in the middle of the smaller balls shows that it .e., lightspreads in greater abundance and more easily around small balls than around big

nes The Nintendo Entertainment System (NES) is an 8-bit third-generation home video game console produced by Nintendo. It was first released in Japan in 1983 as the commonly known as the The NES, a redesigned version, was released in American ...

) Fig. 8 on Plate 6 (following p. 142) shows light at the center of a ball's shadow. he also confirmed earlier (1715) discovery of his pupil

Joseph-Nicolas Delisle Joseph-Nicolas Delisle (; 4 April 1688 – 11 September 1768) was a French astronomer and cartographer. Life Joseph was born in Paris, one of the 11 sons of Claude Delisle (1644–1720). Like many of his brothers, among them Guillaume Delisle, ...

of what is usually referred to as Poisson's spot, an observation that was unrecognized until its rediscovery in the early 19th century by

Dominique Arago "Dominique" is a 1963 French language popular song, written and performed by the Belgian female singer Jeannine Deckers, better known as Sœur Sourire ("Sister Smile" in French) or The Singing Nun. The song is about Saint Dominic, a Spanish-bo ...

. At the time of Arago's discovery, Poisson's spot gave convincing evidence for the contested wave nature of light. In

mathematics Mathematics is an area of knowledge that includes the topics of numbers, formulas and related structures, shapes and the spaces in which they are contained, and quantities and their changes. These topics are represented in modern mathematics ...

he is most known for obtaining the

angle In Euclidean geometry, an angle is the figure formed by two Ray (geometry), rays, called the ''Side (plane geometry), sides'' of the angle, sharing a common endpoint, called the ''vertex (geometry), vertex'' of the angle. Angles formed by two ...

in the

rhombic dodecahedron In geometry, the rhombic dodecahedron is a convex polyhedron with 12 congruent rhombic faces. It has 24 edges, and 14 vertices of 2 types. It is a Catalan solid, and the dual polyhedron of the cuboctahedron. Properties The rhombic dodecahedro ...

shape in 1712, which is still called the Maraldi angle. Craters on the Moon and Mars were named in his and his nephew's honor.

References

External links

History of Mars Observations
1665 births 1729 deaths People from the Province of Imperia Members of the French Academy of Sciences 18th-century French astronomers 17th-century Italian astronomers {{France-mathematician-stub