Geminiano Montanari
Encyclopedia
Geminiano Montanari was an Italian
astronomer
, lens
-maker, and proponent of the experimental approach to science.
He is best known for his observation, made around 1667, that the second brightest star (called Algol in Arabic
) in the constellation of Perseus
varied in brightness. It is likely that others had observed this effect before, but Montanari was the first named astronomer to record it. The star's names in Arabic, Hebrew
and other languages, all of which have a meaning of "ghoul
" or "demon
", imply that its unusual behaviour had long been recognised.
Montanari was born in Modena
, studied law
in Florence
, and graduated from the University of Salzburg
. In 1662 or 1663 he moved to Bologna
, where he drew an accurate map of the Moon
using an ocular micrometer
of his own making. He also made observations on capillarity and other problems in statics
, and suggested that the viscosity
of a liquid depended on the shape of its molecule
s. In 1669 he succeeded Giovanni Cassini
as astronomy teacher at the observatory
of Panzano, near Modena, where one of his duties was to compile an astrological almanac
. He did so in 1665, but perpetrated a deliberate hoax by writing the almanac entirely at random, to show that predictions made by chance were as likely to be fulfilled as those made by astrology. In the period shortly after Galileo Galilei
, experimentalists like Montanari were engaged in a battle against the more mystical views of scientists such as Donato Rossetti.
On 21 March 1676 Montanari reported a sighting of a comet
to Edmund Halley.
Montanari's observations of the great comet of 1680 are mentioned twice in the third volume of Newton's Principia.
In 1679 Montanari moved to a teaching post in Padua
, but almost all records of this period of his life have been lost. A letter survives from 1682 recording a sighting of Halley's Comet. He also wrote on economics
, observing that demand for a particular commodity was fixed, and making comments on coinage and the value of money (1683).
A crater
on the Moon, at 45.8S, 20.6W, is named after him.
Italy
Italy , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and...
astronomer
Astronomy
Astronomy is a natural science that deals with the study of celestial objects and phenomena that originate outside the atmosphere of Earth...
, lens
Lens (optics)
A lens is an optical device with perfect or approximate axial symmetry which transmits and refracts light, converging or diverging the beam. A simple lens consists of a single optical element...
-maker, and proponent of the experimental approach to science.
He is best known for his observation, made around 1667, that the second brightest star (called Algol in Arabic
Arabic language
Arabic is a name applied to the descendants of the Classical Arabic language of the 6th century AD, used most prominently in the Quran, the Islamic Holy Book...
) in the constellation of Perseus
Perseus (constellation)
Perseus is a constellation in the northern sky, named after the Greek hero Perseus. It was one of the 48 constellations listed by the 2nd century astronomer Ptolemy, and remains one of the 88 modern constellations defined by the International Astronomical Union...
varied in brightness. It is likely that others had observed this effect before, but Montanari was the first named astronomer to record it. The star's names in Arabic, Hebrew
Hebrew language
Hebrew is a Semitic language of the Afroasiatic language family. Culturally, is it considered by Jews and other religious groups as the language of the Jewish people, though other Jewish languages had originated among diaspora Jews, and the Hebrew language is also used by non-Jewish groups, such...
and other languages, all of which have a meaning of "ghoul
Ghoul
A ghoul is a folkloric monster associated with graveyards and consuming human flesh, often classified as undead. The oldest surviving literature that mention ghouls is likely One Thousand and One Nights...
" or "demon
Demon
call - 1347 531 7769 for more infoIn Ancient Near Eastern religions as well as in the Abrahamic traditions, including ancient and medieval Christian demonology, a demon is considered an "unclean spirit" which may cause demonic possession, to be addressed with an act of exorcism...
", imply that its unusual behaviour had long been recognised.
Montanari was born in Modena
Modena
Modena is a city and comune on the south side of the Po Valley, in the Province of Modena in the Emilia-Romagna region of Italy....
, studied law
Law
Law is a system of rules and guidelines which are enforced through social institutions to govern behavior, wherever possible. It shapes politics, economics and society in numerous ways and serves as a social mediator of relations between people. Contract law regulates everything from buying a bus...
in Florence
Florence
Florence is the capital city of the Italian region of Tuscany and of the province of Florence. It is the most populous city in Tuscany, with approximately 370,000 inhabitants, expanding to over 1.5 million in the metropolitan area....
, and graduated from the University of Salzburg
University of Salzburg
The University of Salzburg, or Paris Lodron University after its founder, the Prince Archbishop Paris Lodron, is located in the Austrian city of Salzburg, Salzburgerland, home of Mozart. It is divided into 4 faculties: catholic theology, law, humanities and natural science.Founded in 1622, it...
. In 1662 or 1663 he moved to Bologna
Bologna
Bologna is the capital city of Emilia-Romagna, in the Po Valley of Northern Italy. The city lies between the Po River and the Apennine Mountains, more specifically, between the Reno River and the Savena River. Bologna is a lively and cosmopolitan Italian college city, with spectacular history,...
, where he drew an accurate map of the Moon
Moon
The Moon is Earth's only known natural satellite,There are a number of near-Earth asteroids including 3753 Cruithne that are co-orbital with Earth: their orbits bring them close to Earth for periods of time but then alter in the long term . These are quasi-satellites and not true moons. For more...
using an ocular micrometer
Ocular micrometer
An ocular micrometer is a glass disk that fits in a microscope eyepiece that has a ruled scale, which is used to measure the size of magnified objects. The physical length of the marks on the scale depend on the degree of magnification.-External links:*...
of his own making. He also made observations on capillarity and other problems in statics
Statics
Statics is the branch of mechanics concerned with the analysis of loads on physical systems in static equilibrium, that is, in a state where the relative positions of subsystems do not vary over time, or where components and structures are at a constant velocity...
, and suggested that the viscosity
Viscosity
Viscosity is a measure of the resistance of a fluid which is being deformed by either shear or tensile stress. In everyday terms , viscosity is "thickness" or "internal friction". Thus, water is "thin", having a lower viscosity, while honey is "thick", having a higher viscosity...
of a liquid depended on the shape of its molecule
Molecule
A molecule is an electrically neutral group of at least two atoms held together by covalent chemical bonds. Molecules are distinguished from ions by their electrical charge...
s. In 1669 he succeeded Giovanni Cassini
Giovanni Domenico Cassini
This article is about the Italian-born astronomer. For his French-born great-grandson, see Jean-Dominique Cassini.Giovanni Domenico Cassini was an Italian/French mathematician, astronomer, engineer, and astrologer...
as astronomy teacher at the observatory
Observatory
An observatory is a location used for observing terrestrial or celestial events. Astronomy, climatology/meteorology, geology, oceanography and volcanology are examples of disciplines for which observatories have been constructed...
of Panzano, near Modena, where one of his duties was to compile an astrological almanac
Almanac
An almanac is an annual publication that includes information such as weather forecasts, farmers' planting dates, and tide tables, containing tabular information in a particular field or fields often arranged according to the calendar etc...
. He did so in 1665, but perpetrated a deliberate hoax by writing the almanac entirely at random, to show that predictions made by chance were as likely to be fulfilled as those made by astrology. In the period shortly after Galileo Galilei
Galileo Galilei
Galileo Galilei , was an Italian physicist, mathematician, astronomer, and philosopher who played a major role in the Scientific Revolution. His achievements include improvements to the telescope and consequent astronomical observations and support for Copernicanism...
, experimentalists like Montanari were engaged in a battle against the more mystical views of scientists such as Donato Rossetti.
On 21 March 1676 Montanari reported a sighting of a comet
Comet
A comet is an icy small Solar System body that, when close enough to the Sun, displays a visible coma and sometimes also a tail. These phenomena are both due to the effects of solar radiation and the solar wind upon the nucleus of the comet...
to Edmund Halley.
Montanari's observations of the great comet of 1680 are mentioned twice in the third volume of Newton's Principia.
In 1679 Montanari moved to a teaching post in Padua
Padua
Padua is a city and comune in the Veneto, northern Italy. It is the capital of the province of Padua and the economic and communications hub of the area. Padua's population is 212,500 . The city is sometimes included, with Venice and Treviso, in the Padua-Treviso-Venice Metropolitan Area, having...
, but almost all records of this period of his life have been lost. A letter survives from 1682 recording a sighting of Halley's Comet. He also wrote on economics
Economics
Economics is the social science that analyzes the production, distribution, and consumption of goods and services. The term economics comes from the Ancient Greek from + , hence "rules of the house"...
, observing that demand for a particular commodity was fixed, and making comments on coinage and the value of money (1683).
A crater
Montanari (crater)
Montanari is a lunar crater. It is located to the west-southwest of the prominent ray crater Tycho, and is attached to the southern rim of the walled plain Wilhelm...
on the Moon, at 45.8S, 20.6W, is named after him.
Publications
- De motionibus naturalibus a gravitate pendentibus (1667)
- Pensieri fisico-matematici (1667)
- La Livella Diottrica (The Spirit Level) (1674)
- Trattato mercantile delle monete (1680)
- L'Astrologia Convinta di Falso col Mezzo di Nuove Esperienze e Ragioni Fisico-Astronomiche o sia la Caccia del Frugnuolo (1685), in which Montanari describes his and his colleagues' random predictions intended to disprove astrology