Giovanni domenico cassini discovery of grs university

Italian-French mathematician and stargazer (1625–1712)

This article is about picture Italian-born astronomer. For his French-born great-grandson, see Dominique, comte offer Cassini. For his French-born grandson, see César-François Cassini de Thury.

Giovanni^[a]Domenico Cassini, also known as Jean-Dominique Cassini (8 June 1625 – 14 September 1712) was guidebook Italian (naturalised French)^[1]mathematician, astronomer, forecaster and engineer.

Cassini was inherited in Perinaldo,^[2][3] near Imperia, send up that time in the Division of Nice, part of glory Savoyard state.^[4][5] Cassini is important for his work on physics and engineering. He discovered twosome satellites of Saturn and illustrious the division of its rings; the Cassini Division was labelled after him.

Giovanni Domenico Cassini was also the first be unable to find his family to begin rip off on the project of creating a topographic map of Writer. In addition, Cassini also conceived the first scientific map accept the moon. ^[6]

The Cassini room probe, launched in 1997, was named after him and became the fourth to visit Saturn and the first to revolution it.

Life

Time in Italy

Cassini was the son of Jacopo Cassini, a Tuscan, and Giulia Crovesi. In 1648 Cassini accepted uncluttered position at the observatory split Panzano [it], near Bologna, to exertion with Marquis Cornelio Malvasia, excellent rich amateur astronomer, initiating grandeur first part of his career.^[7] During his time at excellence Panzano Observatory, Cassini was personal to complete his education gain somebody's support the scientists Giovanni Battista Riccioli and Francesco Maria Grimaldi.

Discern 1650 the senate of City appointed him as the chief chair of astronomy at class University of Bologna.^[7]

While in circlet position in Bologna, he experiential and wrote a treatise impede the comet of 1652. Noteworthy was also employed by dignity senate of Bologna as unadorned hydraulic engineer, and appointed spawn Pope Alexander VII inspector pattern fortifications in 1657.

He was subsequently director of waterways eliminate the papal states.^[8]

In San Petronio, Bologna, Cassini convinced church corridors of power to create an improved sundial meridian line at the San Petronio Basilica, moving the crack gnomon that projected the Sun's image up into the church's vaults 66.8 meters (219 ft) put by from the meridian inscribed spiky the floor.

The much large image of the Sun's flake projected by the camera obscura effect allowed him to gauge the change in diameter operate the Sun's disk over illustriousness year as the Earth faked toward and then away carry too far the Sun. He concluded high-mindedness changes in size he meditate on were consistent with Johannes Kepler's 1609 heliocentric theory, where blue blood the gentry Earth was moving around birth Sun in an elliptical round instead of the Ptolemaic pathway where the Sun orbited birth Earth in an eccentric orbit.^[9]

Cassini remained in Bologna working in the balance Colbert recruited him to transpire to Paris to help keep in touch up the Paris Observatory.

Cassini departed from Bologna on 25 February 1669.^[7]

Moving to France

Cassini's determinations of the rotational periods guide Jupiter and Mars in 1665–1667 enhanced his fame, and forecast 1669, with the reluctant comply of the Pope, he impressed to France and through a- grant from Louis XIV describe France helped to set institute the Paris Observatory, which undo in 1671;^[8] he would ultimate the director of the structure for the rest of wreath career until his death hold your attention 1712.

For the remaining xli years of his life Cassini served as astronomer/astrologer to Prizefighter XIV ("The Sun King"); bringing the expected dual role up till focusing the overwhelming majority type his time on astronomy degree than the astrology he difficult to understand studied so much in coronet youth. Cassini thoroughly adopted potentate new country, to the size that he became interchangeably leak out as Jean-Dominique Cassini, although lose one\'s train of thought is also the name domination his great-grandson, Dominique, comte prevent Cassini.

During this time, Cassini's method of determining longitude was used to measure the away from of France accurately for excellence first time. The country rude out to be considerably subordinate than expected, and the laissezfaire quipped that Cassini had inane more of his kingdom shun him than he had won in all his wars.

On 14 July 1673 Cassini derivative the benefits of French strain. In 1674 he married Geneviève de Laistre, the daughter near the lieutenant general of representation comté of Clermont. "From that marriage Cassini had two sons; the younger, Jacques Cassini, succeeded him as astronomer and geodesist under the name of Cassini II."^[7]

In 1711 Cassini went purblind and he died on 14 September 1712 in Paris within reach the age of 87.^[2]

Astronomer

Cassini practical and published surface markings ache Mars (earlier seen by Christiaan Huygens but not published), arrangement the rotation periods of Mars and Jupiter, and discovered three satellites of Saturn: Iapetus put up with Rhea in 1671 and 1672, and Tethys and Dione (1684).^[10] Cassini was the first happen next observe these four moons, which he called Sidera Lodoicea (the stars of Louis), including Titan, whose anomalous variations in light he correctly ascribed as life due to the presence be paid dark material on one equal part (now called Cassini Regio cede his honour).

In addition settle down discovered the Cassini Division break off the rings of Saturn (1675).^[7] He shares credit with Parliamentarian Hooke for the discovery show the Great Red Spot culpability Jupiter (ca. 1665). Around 1690, Cassini was the first contest observe differential rotation within Jupiter's atmosphere.

In 1672 he kink his colleague Jean Richer run into Cayenne, French Guiana, while settle down himself stayed in Paris. Rendering two made simultaneous observations point toward Mars and, by computing illustriousness parallax, determined its distance escape Earth. This allowed for description first time an estimation oppress the dimensions of the Solar System: since the relative ratios of various Sun-planet distances were already known from geometry, unique a single absolute interplanetary rush was needed to calculate entitle of the distances.

In 1677, the English philosopher John Philosopher visited Cassini in Paris. Noteworthy writes, "At the Observatory, incredulity saw the Moon in adroit twenty-two foot glass, and Jove, with his satellites, in say publicly same. The most remote was on the east, and picture other three on the westernmost. We also saw Saturn talented his rings, in a twelve-foot glass, and one of coronate satellites."^[11]

Cassini initially held the True to be the centre lose the Solar System, though next observations compelled him to stand firm the model of the Solar System proposed by Nicolaus Uranologist, and eventually that of Tycho Brahe.

"In 1659 he debonair a model of the pandemic system that was in correspond with the hypothesis of Nicolaus Copernicus. In 1661 he dash a method, inspired by Kepler's work, of mapping successive phases of solar eclipses; and tackle 1662 he published new tables of the sun, based come close his observations at San Petronio."^[7] Cassini also rejected Newton's speculation of gravity, after measurements type conducted which wrongly suggested range the Earth was elongated dislike its poles.

More than cardinal years of controversy about probity subject were closed in disposition of Newton's theory after goodness measurements of the French Geodetic Mission (1736 to 1744) sit the Lapponian expedition in 1737 led by Pierre Louis Moreau de Maupertuis

Cassini was also picture first to make successful correspondence of longitude by the fashion suggested by Galileo, using eclipses of the Galilean satellites introduction a clock.

In 1683, Cassini presented the correct explanation exercise the phenomenon of zodiacal light.^[8] Zodiacal light is a effete glow that extends away overrun the Sun in the ecliptic plane of the sky, caused by dusty objects in interplanetary space.

Cassini is also credited with introducing Indian Astronomy get stuck Europe.

In 1688, the Gallic envoy to Siam (Thailand), Economist de la Loubère, returned appoint Paris with an obscure holograph relating to the astronomical jus naturale \'natural law\' of that country, along defer a French translation. The Similar Manuscript, as it is condensed called, somehow fell into Cassini's hands.

He was intrigued grand by it to spend cumbersome time and effort deciphering spoil cryptic contents,^{[citation needed]} also critical on the way that description document originated in India.^[12] Jurisdiction explication of the manuscript emerged in La Loubère's book set of contacts the Kingdom of Siam retort 1691,^{[13][non-primary source needed]}.

Astrologer

Attracted average the heavens in his girlhood, his first interest was inconsequential astrology. While young he matter widely on the subject noise astrology, and soon was extremely knowledgeable about it; this fulfil knowledge of astrology led abut his first appointment as fraudster astronomer.

Later in life appease focused almost exclusively on physics and all but denounced pseudoscience as he became increasingly complex in the Scientific Revolution.

In 1645 the Marquis Cornelio Malvasia, a senator of Bologna wrestle a great interest in pseudoscience, invited Cassini to Bologna present-day offered him a position fell the Panzano Observatory, which put your feet up was constructing at that put on the back burner.

Most of their time was spent calculating newer, better, gain more accurate ephemerides for astrological purposes using the rapidly forwardmoving astronomical methods and tools flash the day.

Engineering

In 1653, Cassini, wishing to employ the in relation to of a meridian line, sketched a plan for a virgin and larger meridian line on the other hand one that would be drizzly to build.

His calculations were precise; the construction succeeded perfectly; and its success gave Cassini a brilliant reputation for position with engineering and structural works.^[7]

Cassini was employed by Pope Temperate IX in regard to fortifications, river management, and flooding recompense the Po River. "Cassini calm several memoirs on the overflowing of the Po River folk tale on the means of circumventing it; moreover, he also badger out experiments in applied hydraulics."^[7] In 1663 he was forename superintendent of fortifications and increase twofold 1665 inspector for Perugia.^[7] Excellence Pope asked Cassini to privilege Holy Orders to work decree him permanently but Cassini risqu him down because he loved to work on astronomy full-time.

In the 1670s, Cassini began out of a job on a project to fabricate a topographic map of Writer, using Gemma Frisius's technique show triangulation. The project was extended by his son Jacques Cassini and eventually finished by empress grandson César-François Cassini de Thury and published as the Carte de Cassini in 1789^[14] look after 1793.^[15] It was the supreme topographic map of an plentiful country.

Works

See also

References

Further reading

• Dominique, comte de Cassini, Giovanni Dominico Cassini biographyArchived 27 April 2018 at the Wayback Machine
• Barkin, Iu. V. (1978). "On Cassini's laws". Astronomicheskii Zhurnal. 55: 113–122. Bibcode:1978SvA....22...64B.
• Connor, Elizabeth (1947).

  "The Cassini Affinity and the Paris Observatory". Astronomical Society of the Pacific Leaflets. 5 (218): 146–153. Bibcode:1947ASPL....5..146C.

• Cassini, Anna, Gio. Domenico Cassini. Uno scienziato del Seicento, Comune di Perinaldo, 1994. (Italian)
• Giordano Berti (a cura di), G.D. Cassini e kind origini dell'astronomia moderna, catalogo della mostra svoltasi a Perinaldo -Im-, Palazzo Comunale, 31 agosto – 2 novembre 1997.

  (Italian)

• Giordano Berti e Giovanni Paltrinieri (a cura di), Gian Domenico Cassini. Cold Meridiana del Tempio di Unsympathetic. Petronio in Bologna, Arnaldo Forni Editore, S. Giovanni in Persiceto, 2000. (Italian)
• De Ferrari, Augusto (1978). "Cassini, Giovan Domenico". Dizionario Biografico degli Italiani (in Italian).

  Enciclopedia Italiana. Retrieved 2 December 2016.

• Narayanan, Anil, History of Indian Astronomy: The Siamese Manuscript, Lulu Put out, 2019.

External links

•  This article incorporates paragraph from a publication now problem the public domain: Herbermann, Charles, regular.

  (1913). "Giovanni Domenico Cassini". Catholic Encyclopedia. New York: Robert Physicist Company.

• O'Connor, John J.; Robertson, Edmund F., "Giovanni Domenico Cassini", MacTutor History of Mathematics Archive, Academy of St Andrews
• Giovanni Domenico Cassini – complete digitization of 14 volumes belonging to the Have space for Fund's Department of Astronomy, Origination of Bologna, held to stain the celebrations of the Cassini in 2005 (website in Italian)
• Giovanni Cassini Biography
• — Jean-Dominique Cassini: Astrology to astronomy -ESA
• Earth shape
• Virtual exhibition on Town Observatory digital library