Julius Plücker
Encyclopedia
Julius Plücker was a German
mathematician
and physicist
. He made fundamental contributions to the field of analytical geometry and was a pioneer in the investigations of cathode ray
s that led eventually to the discovery of the electron
. He also vastly extended the study of Lamé
curves.
(now part of Wuppertal
). After being educated at Düsseldorf
and at the universities of Bonn
, Heidelberg
and Berlin
he went to Paris
in 1823, where he came under the influence of the great school of French geometers, whose founder, Gaspard Monge
, was only recently dead. In 1825 he returned to Bonn, and in 1828 was made professor of mathematics. In the same year he published the first volume of his Analytisch-geometrische Entwicklungen, which introduced for the first time the method of abridged notation. In 1831 he published the second volume, in which he clearly established on a firm and independent basis projective duality.
. In 1858, after a year of working with vacuum tubes of his Bonn colleague Heinrich Geissler
, he published the first of his classical researches on the action of the magnet on the electric discharge in rarefied gases. He found that the discharge caused a fluorescent glow to form on the glass walls of the vacuum tube, and that the glow could be made to shift by applying an electromagnet to the tube, thus creating a magnetic field. It was later shown that the glow was produced by cathode rays.
Plücker, first by himself and afterwards in conjunction with Johann Hittorf
, made many important discoveries in the spectroscopy of gases. He was the first to use the vacuum tube with the capillary part now called a Geissler tube
, by means of which the luminous intensity of feeble electric discharges was raised sufficiently to allow of spectroscopic investigation. He anticipated Robert Wilhelm Bunsen and Gustav Kirchhoff
in announcing that the lines of the spectrum were characteristic of the chemical substance which emitted them, and in indicating the value of this discovery in chemical analysis. According to Hittorf he was the first who saw the three lines of the hydrogen spectrum, which a few months after his death were recognized in the spectrum of the solar protuberances.
In 1865 Plücker returned to the field of geometry and invented what was known as line geometry in the nineteenth century. In projective geometry
, Plücker coordinates
refer to a set of homogeneous co-ordinates introduced initially to embed the set of lines in three dimensions as a quadric
in five dimensions. The construction uses 2×2 minor determinants, or equivalently the second exterior power of the underlying vector space of dimension 4. It is now part of the theory of Grassmannian
s, to which these co-ordinates apply in generality (k-dimensional subspaces of n-dimensional space).
Plücker was the recipient of the Copley Medal
from the Royal Society
in 1866.
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...
mathematician
Mathematician
A mathematician is a person whose primary area of study is the field of mathematics. Mathematicians are concerned with quantity, structure, space, and change....
and physicist
Physicist
A physicist is a scientist who studies or practices physics. Physicists study a wide range of physical phenomena in many branches of physics spanning all length scales: from sub-atomic particles of which all ordinary matter is made to the behavior of the material Universe as a whole...
. He made fundamental contributions to the field of analytical geometry and was a pioneer in the investigations of cathode ray
Cathode ray
Cathode rays are streams of electrons observed in vacuum tubes. If an evacuated glass tube is equipped with two electrodes and a voltage is applied, the glass opposite of the negative electrode is observed to glow, due to electrons emitted from and travelling perpendicular to the cathode Cathode...
s that led eventually to the discovery of the electron
Electron
The electron is a subatomic particle with a negative elementary electric charge. It has no known components or substructure; in other words, it is generally thought to be an elementary particle. An electron has a mass that is approximately 1/1836 that of the proton...
. He also vastly extended the study of Lamé
Gabriel Lamé
Gabriel Léon Jean Baptiste Lamé was a French mathematician.-Biography:Lamé was born in Tours, in today's département of Indre-et-Loire....
curves.
Early years
Plücker was born at ElberfeldElberfeld
Elberfeld is a municipal subdivision of the German city of Wuppertal; it was an independent town until 1929.-History:The first official mentioning of the geographic area on the banks of today's Wupper River as "elverfelde" was in a document of 1161...
(now part of Wuppertal
Wuppertal
Wuppertal is a city in North Rhine-Westphalia, Germany. It is located in and around the Wupper river valley, and is situated east of the city of Düsseldorf and south of the Ruhr area. With a population of approximately 350,000, it is the largest city in the Bergisches Land...
). After being educated at Düsseldorf
Düsseldorf
Düsseldorf is the capital city of the German state of North Rhine-Westphalia and centre of the Rhine-Ruhr metropolitan region.Düsseldorf is an important international business and financial centre and renowned for its fashion and trade fairs. Located centrally within the European Megalopolis, the...
and at the universities of Bonn
Bonn
Bonn is the 19th largest city in Germany. Located in the Cologne/Bonn Region, about 25 kilometres south of Cologne on the river Rhine in the State of North Rhine-Westphalia, it was the capital of West Germany from 1949 to 1990 and the official seat of government of united Germany from 1990 to 1999....
, Heidelberg
Heidelberg
-Early history:Between 600,000 and 200,000 years ago, "Heidelberg Man" died at nearby Mauer. His jaw bone was discovered in 1907; with scientific dating, his remains were determined to be the earliest evidence of human life in Europe. In the 5th century BC, a Celtic fortress of refuge and place of...
and Berlin
Berlin
Berlin is the capital city of Germany and is one of the 16 states of Germany. With a population of 3.45 million people, Berlin is Germany's largest city. It is the second most populous city proper and the seventh most populous urban area in the European Union...
he went to Paris
Paris
Paris is the capital and largest city in France, situated on the river Seine, in northern France, at the heart of the Île-de-France region...
in 1823, where he came under the influence of the great school of French geometers, whose founder, Gaspard Monge
Gaspard Monge
Gaspard Monge, Comte de Péluse was a French mathematician, revolutionary, and was inventor of descriptive geometry. During the French Revolution, he was involved in the complete reorganization of the educational system, founding the École Polytechnique...
, was only recently dead. In 1825 he returned to Bonn, and in 1828 was made professor of mathematics. In the same year he published the first volume of his Analytisch-geometrische Entwicklungen, which introduced for the first time the method of abridged notation. In 1831 he published the second volume, in which he clearly established on a firm and independent basis projective duality.
Career
In 1836 Plücker was made professor of physics at University of BonnUniversity of Bonn
The University of Bonn is a public research university located in Bonn, Germany. Founded in its present form in 1818, as the linear successor of earlier academic institutions, the University of Bonn is today one of the leading universities in Germany. The University of Bonn offers a large number...
. In 1858, after a year of working with vacuum tubes of his Bonn colleague Heinrich Geissler
Heinrich Geissler
Johann Heinrich Wilhelm Geißler was a German physicist and inventor of the Geissler tube, a low pressure gas-discharge tube made of glass....
, he published the first of his classical researches on the action of the magnet on the electric discharge in rarefied gases. He found that the discharge caused a fluorescent glow to form on the glass walls of the vacuum tube, and that the glow could be made to shift by applying an electromagnet to the tube, thus creating a magnetic field. It was later shown that the glow was produced by cathode rays.
Plücker, first by himself and afterwards in conjunction with Johann Hittorf
Johann Wilhelm Hittorf
Johann Wilhelm Hittorf was a German physicist who was born in Bonn and died in Münster, Germany.Hittorf was the first to compute the electricity-carrying capacity of charged atoms and molecules , an important factor in understanding electrochemical reactions...
, made many important discoveries in the spectroscopy of gases. He was the first to use the vacuum tube with the capillary part now called a Geissler tube
Geissler tube
A Geissler tube is an early gas discharge tube used to demonstrate the principles of electrical glow discharge. The tube was invented by the German physicist and glassblower Heinrich Geissler in 1857...
, by means of which the luminous intensity of feeble electric discharges was raised sufficiently to allow of spectroscopic investigation. He anticipated Robert Wilhelm Bunsen and Gustav Kirchhoff
Gustav Kirchhoff
Gustav Robert Kirchhoff was a German physicist who contributed to the fundamental understanding of electrical circuits, spectroscopy, and the emission of black-body radiation by heated objects...
in announcing that the lines of the spectrum were characteristic of the chemical substance which emitted them, and in indicating the value of this discovery in chemical analysis. According to Hittorf he was the first who saw the three lines of the hydrogen spectrum, which a few months after his death were recognized in the spectrum of the solar protuberances.
In 1865 Plücker returned to the field of geometry and invented what was known as line geometry in the nineteenth century. In projective geometry
Projective geometry
In mathematics, projective geometry is the study of geometric properties that are invariant under projective transformations. This means that, compared to elementary geometry, projective geometry has a different setting, projective space, and a selective set of basic geometric concepts...
, Plücker coordinates
Plücker coordinates
In geometry, Plücker coordinates, introduced by Julius Plücker in the 19th century, are a way to assign six homogenous coordinates to each line in projective 3-space, P3. Because they satisfy a quadratic constraint, they establish a one-to-one correspondence between the 4-dimensional space of lines...
refer to a set of homogeneous co-ordinates introduced initially to embed the set of lines in three dimensions as a quadric
Quadric
In mathematics, a quadric, or quadric surface, is any D-dimensional hypersurface in -dimensional space defined as the locus of zeros of a quadratic polynomial...
in five dimensions. The construction uses 2×2 minor determinants, or equivalently the second exterior power of the underlying vector space of dimension 4. It is now part of the theory of Grassmannian
Grassmannian
In mathematics, a Grassmannian is a space which parameterizes all linear subspaces of a vector space V of a given dimension. For example, the Grassmannian Gr is the space of lines through the origin in V, so it is the same as the projective space P. The Grassmanians are compact, topological...
s, to which these co-ordinates apply in generality (k-dimensional subspaces of n-dimensional space).
Plücker was the recipient of the Copley Medal
Copley Medal
The Copley Medal is an award given by the Royal Society of London for "outstanding achievements in research in any branch of science, and alternates between the physical sciences and the biological sciences"...
from the Royal Society
Royal Society
The Royal Society of London for Improving Natural Knowledge, known simply as the Royal Society, is a learned society for science, and is possibly the oldest such society in existence. Founded in November 1660, it was granted a Royal Charter by King Charles II as the "Royal Society of London"...
in 1866.
See also
- Plücker's conoid
- Plücker coordinatesPlücker coordinatesIn geometry, Plücker coordinates, introduced by Julius Plücker in the 19th century, are a way to assign six homogenous coordinates to each line in projective 3-space, P3. Because they satisfy a quadratic constraint, they establish a one-to-one correspondence between the 4-dimensional space of lines...
- Plücker embeddingPlücker embeddingIn mathematics, the Plücker embedding describes a method to realize the Grassmannian of all r-dimensional subspaces of a vector space V as a subvariety of the projective space of the rth exterior power of that vector space, P....
- Plücker formulaPlücker formulaIn mathematics, a Plücker formula, named after Julius Plücker, is one of a family of formulae, of a type first developed by Plücker in the 1830s, that relate certain numeric invariants of algebraic curves to corresponding invariants of their dual curves. The invariant called the genus, common to...
- Plücker surfacePlücker surfaceIn algebraic geometry, a Plücker surface, studied by , is a quartic surface in 3-dimensional projective space with a double line and 8 nodes.-Construction:For any quadric line complex, the lines of the complex in a plane envelop a quadric in the plane...
- Timeline of low-temperature technologyTimeline of low-temperature technologyThe following is a timeline of low-temperature technology and cryogenic technology .-16th century BCE – 17th century CE :...
External links
- The Cathode Ray Tube site
- Eintrag in der ADB
- Julius Plücker in der philosophischen Fakultät der Universität Halle (PDF)
- Julius Plücker und die Stammfolge der Familie Plücker, Deutsches Geschlechterbuch, 217. Bd., A. Starke Verlag, Limburg a.d.L. 2004 (WordWordIn language, a word is the smallest free form that may be uttered in isolation with semantic or pragmatic content . This contrasts with a morpheme, which is the smallest unit of meaning but will not necessarily stand on its own...
) - uni-bonn.de „Ein streitbarer Gelehrter im 19. Jahrhundert. Der Mathematiker Julius Plücker starb vor 140 Jahren.“ Pressemitteilung der Universität Bonn vom 21. Mai 2008