See Also

Johannes Kepler

Johannes Kepler , a key figure in the scientific revolution, was a German Germans

Germans are defined as an ethnic group [i], or Volk [i], in the sense of sharing a common German culture [i] ... 

 mathematician Mathematician

A mathematician is a person whose primary area of study and research is the field of mathematics [i]. ... 

, astronomer Astronomer

An astronomer or astrophysicist is a person whose area of interest is astronomy [i] or astrophysics [i] ... 

, astrologer, and an early writer of science fiction Science fiction

Science fiction is a popular genre of fiction in which the narrative world differs from our own present... 

 stories. He is best known for his laws of planetary motion Kepler's laws of planetary motion

Johannes Kepler [i]'s primary contributions to astronomy [i]/astrophysics [i] were his three laws of planet ... 

, based on his works Astronomia nova, Harmonice Mundi and the textbook Epitome of Copernican Astronomy. Through his career Kepler was a mathematics teacher at a Graz seminary school , an assistant to Tycho Brahe Tycho Brahe

Tycho Brahe , born Tyge Ottesen Brahe , was a Danish [i] nobleman [i] best know ... 

, court mathematician to Emperor Rudolf II Rudolf II, Holy Roman Emperor

Rudolf II von Habsburg [i] was an emperor of the Holy Roman Empire [i], King of Bohemia [i], and King o ... 

, mathematics teacher in Linz Linz

Linz is a statutory city [i] in northeastern Austria [i], by the Danube [i] river. ... 

, Austria Austria

Austria is a landlocked [i] country in central Europe [i]. ... 

, and court astrologer to General Wallenstein Albrecht von Wallenstein

Albrecht Wenzel Eusebius von Wallenstein, September 24 [i], 1583 [i] – February 25 [i], 1634 [i]) ... 

.

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Timeline

1571   Born

1609   Johannes Kepler publishes his first two laws of planetary motion Kepler's laws of planetary motion

Johannes Kepler [i]'s primary contributions to astronomy [i]/astrophysics [i] were his three laws of planet ... 

 in ''Astronomia Nova''

1618   Johannes Kepler discovers the third law of planetary motion Kepler's laws of planetary motion

Johannes Kepler [i]'s primary contributions to astronomy [i]/astrophysics [i] were his three laws of planet ... 

 (he soon rejects the idea after some initial calculations were made but on May 15 confirms the discovery).

1630   Died


Quotations

Discover the force of the heavens O Men: once recognised it can be put to use.

De Fundamentis On the more Certain Fundamentals of Astrology or On Giving Astrology Sounder Foundations (1601)

Nature uses as little as possible of anything.

Viking Book of Aphorisms: A Personal Selection (1920) by W. H. Auden and Louis Kronenberger, p. 98; also in The Infinite Cosmos: Questions from the Frontiers of Cosmology (2006) by Joseph Silk

In Terra inest virtus, quae Lunam del.

There is a force in the earth which causes the moon to move., Essay dedicated to the Archduke Ferdinand, as quoted in Kepler (1993) by Max Caspar, Sect. II, Ch. 9, p. 110

I much prefer the sharpest criticism of a single intelligent man to the thoughtless approval of the masses.

As quoted in (K)new Words: Redefine Your Communication (2005) by Gloria Pierre, p. 147

       More Quotes >>


Encyclopedia


Johannes Kepler , a key figure in the scientific revolution, was a German Germans

Germans are defined as an ethnic group [i], or Volk [i], in the sense of sharing a common German culture [i] ... 

 mathematician Mathematician

A mathematician is a person whose primary area of study and research is the field of mathematics [i]. ... 

, astronomer Astronomer

An astronomer or astrophysicist is a person whose area of interest is astronomy [i] or astrophysics [i] ... 

, astrologer, and an early writer of science fiction Science fiction

Science fiction is a popular genre of fiction in which the narrative world differs from our own present... 

 stories. He is best known for his laws of planetary motion Kepler's laws of planetary motion

Johannes Kepler [i]'s primary contributions to astronomy [i]/astrophysics [i] were his three laws of planet ... 

, based on his works Astronomia nova, Harmonice Mundi and the textbook Epitome of Copernican Astronomy.

Through his career Kepler was a mathematics teacher at a Graz seminary school , an assistant to Tycho Brahe Tycho Brahe

Tycho Brahe , born Tyge Ottesen Brahe , was a Danish [i] nobleman [i] best know ... 

, court mathematician to Emperor Rudolf II Rudolf II, Holy Roman Emperor

Rudolf II von Habsburg [i] was an emperor of the Holy Roman Empire [i], King of Bohemia [i], and King o ... 

, mathematics teacher in Linz Linz

Linz is a statutory city [i] in northeastern Austria [i], by the Danube [i] river. ... 

, Austria Austria

Austria is a landlocked [i] country in central Europe [i]. ... 

, and court astrologer to General Wallenstein Albrecht von Wallenstein

Albrecht Wenzel Eusebius von Wallenstein, September 24 [i], 1583 [i] – February 25 [i], 1634 [i]) ... 

. He also did fundamental work in the field of optics Optics

Optics is a branch of physics [i] that describes the behavior and properties of light [i] and the inter ... 

 and helped to legitimize the telescopic discoveries of his contemporary Galileo Galilei Galileo Galilei

Galileo Galilei was an Italian [i] physicist [i], astronomer [i], astrologer [i] and philosopher [i] ... 

.

He is sometimes referred to as "the first theoretical astrophysicist Theoretical Astrophysics

Sorry, no overview for this topic 

", although Carl Sagan Carl Sagan

Dr. Carl Edward Sagan was an American [i] astronomer [i], astrobiologist [i]... 

 also referred to him as the last scientific astrologer.

Life


Childhood and education

Kepler was born on December 27 1571 at the Imperial Free City of Weil der Stadt Weil der Stadt

Weil der Stadt is a small town with approximately 19,200 inhabitants, located in the [[Stuttgart Region]... 

 . His grandfather had been Lord Mayor of that town, but by the time Johannes was born, the Kepler family fortunes were in decline. His father earned a precarious living as a mercenary Mercenary

A mercenary is a soldier [i] who fights, or engages in warfare primarily for private gain, usually with ... 

, and he left the family when Johannes was five years old. He was believed to have died in the war in the Netherlands. His mother, an inn-keeper's daughter, was a healer and herbalist who was later tried for witchcraft Witchcraft

Witchcraft, in various historical, religious and mythical contexts, is the use of certain kinds of alleg... 

. Born prematurely, Johannes claimed to have been a weak and sickly child. Despite his ill health, he was precociously brilliant. As a child, he often impressed travelers at his grandfather's inn with his phenomenal mathematical faculty.

He was introduced to astronomy/astrology at an early age, and he developed a love for it that would span his entire life. At age five, he observed the Comet Comet

A comet is a small body in the solar system that orbits the Sun [i] and exhibits a coma [i] and/ ... 

 of 1577, writing that he "was taken by [his] mother to a high place to look at it." At age nine, he observed another astronomical event, the Lunar eclipse Lunar eclipse

An eclipse [i] refers to the phenomenon of one body passing into the shadow cast by another body. ... 

 of 1580, recording that he remembered being "called outdoors" to see it and that the moon "appeared quite red". However, childhood smallpox Smallpox

Smallpox was a highly contagious viral disease [i] unique to humans.... 

 left him with weak vision, limiting him to the mathematical rather than observational aspects of astronomy.

In 1589, after moving through grammar school, Latin school, and lower and higher seminary in the Lutheran education system, Kepler began attending the University of Tübingen as a theology student, where he proved himself to be a superb mathematician and earned a reputation as a skillful astrologer Astrology

Astrology is a group of system [i]s, tradition [i]s, and belief [i]s in which knowledge of the relative ... 

. Under the instruction of Michael Maestlin, he learned both the Ptolemaic system Geocentric model

In astronomy [i], the geocentric model of the universe [i] is the theory [i] that the Earth [i] is at th ... 

 and the Copernican system Heliocentrism

In astronomy [i], heliocentrism is the theory [i] that the Sun [i] is at the center of the Universe [i]... 

; he became a Copernican at that time, defending heliocentrism Heliocentrism

In astronomy [i], heliocentrism is the theory [i] that the Sun [i] is at the center of the Universe [i]... 

 from both a theoretical and theological perspective in student debates. Despite his desire to become a minister, near the end of his studies, Kepler was recommended for a position as teacher of mathematics and astronomy at the Protestant school in Graz Graz

Graz [gra?ts] , with a population of 285,470 as of 2006 [i] , is the second-largest city [i] ... 

, Austria Austria

Austria is a landlocked [i] country in central Europe [i]. ... 

. He accepted the position in April 1594, at the age of 23.


Early career

In Graz, Kepler began developing an original theory of cosmology based on the Copernican system, which was published in 1596 as Mysterium CosmographicumThe Sacred Mystery of the Cosmos.

In April 1597, Kepler married Barbara Müller. She died in 1611 and was outlived by two of Johannes's children and one by an earlier marriage.

In December 1599, Tycho Brahe Tycho Brahe

Tycho Brahe , born Tyge Ottesen Brahe , was a Danish [i] nobleman [i] best know ... 

 wrote to Kepler, inviting Kepler to assist him at Benátky nad Jizerou Benátky nad Jizerou

... 

 outside Prague Prague

Prague is the capital [i] and largest city of the Czech Republic [i]. ... 

. Pressured to leave Graz by increasingly strict Counter-Reformation Counter-Reformation

The Counter-Reformation or Catholic Reformation was a movement within the Catholic Church [i] ... 

 policies restricting the religious practices and political rights of Protestants, Kepler joined Tycho in 1600. After Tycho's death in 1601, Kepler was appointed Imperial Mathematician in his place, a post he would retain through the reigns of three Habsburg Habsburg

Habsburg was an important ruling house [i] of Europe [i] and is best known as the ruling Ho ... 

 Emperors .


Imperial Mathematician in Prague

As Imperial Mathematician, Kepler inherited Tycho's responsibility for the Emperor's horoscope Horoscope

In astrology [i], a horoscope is a chart or diagram representing the positions of the planets, other cel ... 

s as well as the commission to produce the Rudolphine Tables Rudolphine Tables

[i] catalog and planetary tables published by [[Johannes Kepler]... 

. Working with Tycho's extensive collection of highly accurate observational data, Kepler also set out to refine his earlier theories but was forced to abandon them. Instead, he began developing the first astronomical system to use non-circular orbits; it was completed in 1606 and published in 1609 as Astronomia NovaNew Astronomy. Astronomia Nova contained what would become the first and second laws of planetary motion Kepler's laws of planetary motion

Johannes Kepler [i]'s primary contributions to astronomy [i]/astrophysics [i] were his three laws of planet ... 

.

In October 1604, Kepler observed the supernova Supernova

A supernova is a stellar [i] explosion [i] which produces an extremely bright [i] ... 

 which was subsequently named Kepler's Star SN 1604

Supernova 1604, also known as Kepler's Supernova or Kepler's Star, was a supernova [i] in th ... 

 . In 1611, Kepler published a monograph on the origins of snow Snow

Snow is precipitation [i] in the form of crystal [i]line water [i] ice [i], consisting of... 

flakes, the first known work on the subject. He correctly theorized that their hexagonal nature was due to cold, but did not ascertain a physical cause for this. In January 1612, the Emperor died. To escape the growing religious tension in Prague, Kepler took the post of Provincial Mathematician in Linz Linz

Linz is a statutory city [i] in northeastern Austria [i], by the Danube [i] river. ... 

.

Teaching in Linz and final years

In 1615, Kepler married Susanna Ruettinger, with whom he would have several children.

In 1617, Kepler's mother Katharina was accused of being a witch in Leonberg. Beginning in August 1620 she was imprisoned for fourteen months. Thanks in part to the extensive legal defense drawn up by Kepler, she was released in October 1621 after failed attempts to convict her. However, she was subjected to territio verbalis, a graphic description of the torture Torture

Torture is any act by which severe pain, whether physical or psychological [i], is intentiona... 

 awaiting her as a witch, in a final attempt to make her confess. Throughout the trial, Kepler postponed his other work to focus on his "harmonic theory". The result, published in 1619 as Harmonices Mundi contained the third law of planetary motion.

Kepler completed the last of seven volumes of his textbook Epitome of Copernican Astronomy in 1621, which brought together and extended his previous work and would become very influential in the acceptance of the Copernican system over the next century. In 1627 he completed the Rudolphine Tables, which provided accurately calculated future positions of the planets and allowed the prediction of rare astronomical events.

On November 15, 1630 Kepler died of a fever in Regensburg Regensburg

Regensburg is a city in Bavaria [i], south-east Germany [i], located at the confluence of the Danube [i] ... 

. In 1632, only two years after his death, his grave was demolished by the Swedish Sweden

The Kingdom of Sweden is a Nordic country [i] in Scandinavia [i]. ... 

 army in the Thirty Years' War Thirty Years' War

The Thirty Years' War was fought between 1618 [i] and 1648 [i], principally on the territory of today's ... 

. Kepler had incidentally composed the epitaph for his own tombstone, which read :

I measured the skies ,now the shadows I measure,
Sky-bound was the mind, earth-bound the body rests

Work

Kepler lived in an era when there was no clear distinction between astronomy Astronomy

Astronomy is the science [i] of celestial objects and phenomena [i] that originate outside the Earth's atmosphere [i] ... 

 and astrology Astrology

Astrology is a group of system [i]s, tradition [i]s, and belief [i]s in which knowledge of the relative ... 

, while there was a strong division between astronomy/astrology and physics Physics

Physics , the most fundamental physical science [i], is concerned with the underlying principles of the ... 

 . He also incorporated religious arguments and reasoning into his work, such that the basis for many of his most important contributions was essentially theological .

Kepler was a Pythagorean Pythagoras

Pythagoras of Samos was an Ionian [i] mathematician [i] and philosopher [i], founder of the my ... 

 mystic. He considered mathematical relationships to be at the base of all nature, and all creation to be an integrated whole. This was in contrast to the Plato Plato

Plato , whose real name is believed to have been Aristocles, was an immensely influential ancient... 

nic and Aristotelian Aristotle

Aristotle was an ancient Greek [i] philosopher [i], a student of Plato [i] ... 

 notion that the Earth was fundamentally different from the rest of the universe, being composed of different substances and with different natural laws applying. In his attempt to discover universal laws, Kepler applied terrestrial physics to celestial bodies; famously, his effort produced the three Laws of Planetary Motion. Kepler was also convinced that celestial bodies influence terrestrial events. One result of this belief was his correct assessment of the moon's role in generating the tides Tide

The tide is the cyclic rising and falling of Earth's ocean [i] surface caused by the tidal force [i]s of ... 

, years before Galileo's incorrect formulation. Another was his belief that someday it would be possible to develop a "scientific astrology", despite his general disdain for most of the astrology of his time.

Scientific work


Kepler's laws
Kepler inherited from Tycho Brahe Tycho Brahe

Tycho Brahe , born Tyge Ottesen Brahe , was a Danish [i] nobleman [i] best know ... 

 a wealth of the most accurate raw data ever collected on the positions of the planet Planet

The International Astronomical Union [i] , the official scientific [i] body for astronomical [i] nomenclature [i]... 

s. The difficulty was to make sense of it. The orbital motions of the other planets are viewed from the vantage point of the Earth, which is itself orbiting the sun. As shown in the example below, this can cause the other planets to appear to move in strange loops. Kepler concentrated on trying to understand the orbit of Mars Mars

Mars is the fourth planet [i] from the Sun [i] in our solar system [i] and is named after Mars [i] ... 

, but he had to know the orbit of the Earth accurately first. In order to do this, he needed a surveyor's baseline. In a stroke of pure genius, he used Mars and the Sun as his baseline, since without knowing the actual orbit of Mars, he knew that it would be in the same place in its orbit at times separated by its orbital period. Thus the orbital positions of the Earth could be computed, and from them the orbit of Mars. He was able to deduce his planetary laws without knowing the exact distances of the planets from the sun, since his geometrical analysis needed only the ratios of their solar distances.



Unlike Brahe, Kepler held to the heliocentric model of the solar system. Starting from that framework, Kepler made twenty years of painstaking trial-and-error attempts at making some sense out of the data. He finally arrived at his three laws of planetary motion Kepler's laws of planetary motion

Johannes Kepler [i]'s primary contributions to astronomy [i]/astrophysics [i] were his three laws of planet ... 

:



  1. Kepler's elliptical orbit law: The planets orbit the sun in elliptical orbits with the sun at one focus.
  2. Kepler's equal-area law: The line connecting a planet to the sun sweeps out equal areas in equal amounts of time.
  3. Kepler's law of periods: The time required for a planet to orbit the sun, called its period, is proportional to the long axis of the ellipse raised to the 3/2 power. The constant of proportionality is the same for all the planets.


Using these laws, he was the first astronomer to successfully predict a transit of Venus Transit of Venus

A transit of Venus across the Sun [i] takes place when the planet [i] Venus [i] passes directly be ... 

 . Kepler's laws were the first clear evidence in favor of the heliocentric model of the solar system, because they only came out to be so simple under the heliocentric assumption. Kepler, however, never discovered the deeper reasons for the laws, despite many years of what would now be considered non-scientific mystical speculation. Isaac Newton Isaac Newton

[i] [[[Old Style and New Style dates|OS]] [i]: [[25 December]] [i] [[1642]] [i]... 

 eventually showed that the laws were a consequence of his laws of motion Newton's laws of motion

Newton's Laws of Motion are three physical law [i]s which provide relationships [i] ... 

 and law of universal gravitation Newton's law of universal gravitation

Isaac Newton [i]'s law of universal gravitation [i] states the following:
... 

.

Kepler first discovered his distance-cubed-over-time-squared law of planetary motion on March 8, 1618 but rejected the idea until May 15, 1618, when he verified his result. This result was published in his Harmonices Mundi .
Supernova 1604


On October 17, 1604, Kepler observed that an exceptionally bright star had suddenly appeared in the constellation Ophiuchus Ophiuchus

Ophiuchus is one of the 88 constellation [i]s, and was also one of the 48 listed by Ptolemy [i]. ... 

. The appearance of the star, which Kepler described in his book De Stella nova in pede Serpentarii , provided further evidence that the cosmos were not changeless; this was to influence Galileo Galilei in his argument. It has since been determined that the star was a supernova Supernova

A supernova is a stellar [i] explosion [i] which produces an extremely bright [i] ... 

, the second in a generation, later called Kepler's Star SN 1604

Supernova 1604, also known as Kepler's Supernova or Kepler's Star, was a supernova [i] in th ... 

 or Supernova 1604 SN 1604

Supernova 1604, also known as Kepler's Supernova or Kepler's Star, was a supernova [i] in th ... 

. No further supernovae have been observed in the Milky Way Milky Way

The Milky Way , is a barred spiral galaxy [i] which forms part of the Local Group [i]. ... 

, though others outside our galaxy have been seen.
Other scientific and mathematical work
Kepler also made fundamental investigations into combinatorics, geometrical optimization, and natural phenomena such as snow Snow

Snow is precipitation [i] in the form of crystal [i]line water [i] ice [i], consisting of... 

flakes, always with an emphasis on form and design. He was also one of the founders of modern optics Optics

Optics is a branch of physics [i] that describes the behavior and properties of light [i] and the inter ... 

, defining for example antiprism Antiprism

An n-sided antiprism is a polyhedron [i] composed of two parallel copies of some particular n-si ... 

s and the Kepler telescope Telescope

The word "telescope" usually refers to optical telescope [i]s, but there are telescopes for most of the ... 

 . In addition, since he was the first to recognize the non-convex regular solids , they are named Kepler solid Kepler-Poinsot solid

A Kepler-Poinsot solid is a regular non-convex polyhedron [i], all the faces of which are identical regu ... 

s in his honor.

Kepler also was in contact with Wilhelm Schickard Wilhelm Schickard

Wilhelm Schickard built the first automatic calculator [i] in 1623.
... 

, inventor of the first automatic calculator Calculator

A calculator is a device for performing calculation [i]s.... 

, whose
letters to Kepler show how to use the machine for calculating astronomical tables.

Mysticism and astrology


Mysticism
Kepler discovered the laws of planetary motion while trying to achieve the Pythagorean purpose of finding the harmony of the celestial spheres. In his cosmologic vision, it was not a coincidence that the number of perfect polyhedra Platonic solid

In geometry [i], a Platonic solid is a convex [i] regular polyhedron [i]. ... 

 was one less than the number of known planet Planet

The International Astronomical Union [i] , the official scientific [i] body for astronomical [i] nomenclature [i]... 

s. Having embraced the Copernican system, he set out to prove that the distances from the planets to the sun were given by spheres inside perfect polyhedra, all of which were nested inside each other. The smallest orbit, that of Mercury, was the innermost sphere. He thereby identified the five Platonic solid Platonic solid

In geometry [i], a Platonic solid is a convex [i] regular polyhedron [i]. ... 

s with the five intervals between the six known planets and the five classical elements.

In 1596 Kepler published Mysterium Cosmographicum, or The Sacred Mystery of the Cosmos. Here is a selection explaining the relation between the planets and the Platonic solids:
Before the universe was created, there were no numbers except the Trinity, which is God himself… For, the line and the plane imply no numbers: here infinitude itself reigns. Let us consider, therefore, the solids. We must first eliminate the irregular solids, because we are only concerned with orderly creation. There remain six bodies, the sphere and the five regular polyhedra. To the sphere Sphere

A sphere is a perfectly symmetrical [i] geometrical [i] object. ... 

 corresponds the heaven. On the other hand, the dynamic world is represented by the flat-faces solids. Of these there are five: when viewed as boundaries, however, these five determine six distinct things: hence the six planets that revolve about the sun. This is also the reason why there are but six planets…




I have further shown that the regular solids fall into two groups: three in one, and two in the other. To the larger group belongs, first of all, the Cube Cube

A cube is a three-dimensional [i] Platonic solid [i] composed of six square [i] ... 

, then the Pyramid Tetrahedron

A tetrahedron is a polyhedron [i] composed of four triangular faces, three of which meet at each vertex [i] ... 

, and finally the Dodecahedron Dodecahedron

A dodecahedron is any polyhedron [i] with twelve faces, but usually a regular dodecahedron is mean ... 

. To the second group belongs, first, the Octahedron Octahedron

An octahedron is a polyhedron [i] with eight faces. ... 

, and second, the Icosahedron Icosahedron

An icosahedron noun is

... 

. That is why the most important portion of the universe, the Earth—where God's image is reflected in man—separates the two groups. For, as I have proved next, the solids of the first group must lie beyond the earth's orbit, and those of the second group within… Thus I was led to assign the Cube to Saturn, the Tetrahedron to Jupiter, the Dodecahedron to Mars, the Icosahedron to Venus, and the Octahedron to Mercury…

To emphasize his theory, Kepler envisaged an impressive model of the universe which shows a cube, inside a sphere, with a tetrahedron inscribed in it; another sphere inside it with a dodecahedron inscribed; a sphere with an icosahedron inscribed inside; and finally a sphere with an octahedron inscribed. Each of these celestial spheres had a planet embedded within them, and thus defined the planet's orbit.

In his 1619 book, Harmonice Mundi or Harmony of the Worlds, as well as the aforementioned Mysterium Cosmographicum, he also made an association between the Platonic solid Platonic solid

In geometry [i], a Platonic solid is a convex [i] regular polyhedron [i]. ... 

s with the classical conception of the elements: the tetrahedron Tetrahedron

A tetrahedron is a polyhedron [i] composed of four triangular faces, three of which meet at each vertex [i] ... 

 was the form of fire, the octahedron Octahedron

An octahedron is a polyhedron [i] with eight faces. ... 

 was that of air, the cube Cube

A cube is a three-dimensional [i] Platonic solid [i] composed of six square [i] ... 

 was earth, the icosahedron Icosahedron

An icosahedron noun is
... 

 was water, and the dodecahedron Dodecahedron

A dodecahedron is any polyhedron [i] with twelve faces, but usually a regular dodecahedron is mean ... 

 was the cosmos as a whole or ether. There is some evidence this association was of ancient origin, as Plato Plato

Plato , whose real name is believed to have been Aristocles, was an immensely influential ancient... 

 tells of one Timaeus of Locri who thought of the Universe as being enveloped by a gigantic dodecahedron while the other four solids represent the "elements" of fire, air, earth, and water.
To his disappointment, Kepler's attempts to fix the orbits of the planets within a set of polyhedrons never worked out, but it is a testimony to his integrity as a scientist that when the evidence mounted against the cherished theory he worked so hard to prove, he abandoned it.

His most significant achievements came from the realization that the planets moved in elliptical, not circular, orbits. This realization was a direct consequence of his failed attempt to fit the planetary orbits within polyhedra. Kepler's willingness to abandon his most cherished theory in the face of precise observational evidence also indicates that he had a very modern attitude to scientific research. Kepler also made great steps in trying to describe the motion of the planets by appealing to a force which resembled magnetism, which he believed emanated from the sun. Although he did not discover gravity Gravitation

In physics [i], gravitation or gravity is the tendency of objects with mass [i] to accelerate [i] ... 

, he seems to have attempted to invoke the first empirical example of a universal law to explain the behaviour of both earthly and heavenly bodies.
Astrology
Kepler disdained astrologers who pandered to the tastes of the common man without knowledge of the abstract and general rules, but he saw compiling prognostications as a justified means of supplementing his meager income. Yet, it would be a mistake to take Kepler's astrological interests as merely pecuniary. As one historian, John North, put it, "had he not been an astrologer he would very probably have failed to produce his planetary astronomy in the form we have it." However, Kepler's views on astrology were quite unconventional for his time; he argued for a system of astrology based largely on harmonics, a type of 'planetary harmonics' based almost entirely upon the astrological aspects Astrological aspect

In astrology [i], an aspect is the relative angle [i] between two heavenly bodies [i]. ... 

 and what has been traditionally been termed "the music of the spheres." Information relating to his theories can be found in his book Harmonice Mundi.

Kepler believed in astrology in the sense that he was convinced that astrological aspects Astrological aspect

In astrology [i], an aspect is the relative angle [i] between two heavenly bodies [i]. ... 

 physically and really affected humans Human

Humans, or human beings, are biped [i]al primate [i]s belonging to the mammal [i]ian species ... 

 as well as the weather Weather

Weather is an all-encompassing term used to describe all of the many and varied phenomena [i] that c ... 

 on Earth. He strove to unravel how and why that was the case and tried to put astrology on a surer footing, which resulted in the On the More Certain Fundamentals of Astrology , in which, among other technical innovations, he was the first to propose a number of new aspects such as 18°, 24°, 30° , 36°, 45° , 72° , 108°, 135° , 144° , and 150° . In The Intervening Third Man, or a warning to theologians Theology

Theology is reasoned discourse [i] concerning religion [i], spirituality [i] and God [i]. ... 

, physicians Physician

A physician is a person who practices biological medicine [i]. ... 

 and philosophers Philosophy

[i]
... 

 , posing as a third man between the two extreme positions for and against astrology Astrology

Astrology is a group of system [i]s, tradition [i]s, and belief [i]s in which knowledge of the relative ... 

, Kepler advocated that a definite relationship between heavenly phenomena and earthly events could be established.

At least 800 horoscopes and natal chart Natal chart

In astrology [i], a natal chart is a horoscope [i] drawn for the exact time of an individual's birth for ... 

s drawn up by Kepler are still extant, several of himself and his family, accompanied by some unflattering remarks. As part of his duties as district mathematician to Graz, Kepler issued a prognostication for 1595 in which he forecast a peasant Peasant

A peasant, from 15th century [i] French pasant meaning one from the pays, the countryside [i] ... 

 uprising, Turkish Turkey

Turkey, officially the Republic of Turkey, is a Eurasia [i]n country that stretches across the Anatolia [i] ... 

 invasion and bitter cold, all of which happened and brought him renown. Kepler is known to have compiled prognostications for 1595 to 1606, and from 1617 to 1624. As court mathematician, Kepler explained to Rudolf II Rudolf II, Holy Roman Emperor

Rudolf II von Habsburg [i] was an emperor of the Holy Roman Empire [i], King of Bohemia [i], and King o ... 

 the horoscopes of the Emperor Augustus and the Prophet Muhammad Muhammad

Muhammad 570 [i]-632 [i] CE, was an Arab [i] religious and political leader and the historical founde ... 

, and Kepler gave astrological prognosis for the outcome of a war between the Republic of Venice Venice

Venice is the capital [i] of the region [i] of Veneto [i] and the province of the same name [i] ... 

 and Paul V Pope Paul V

Pope Paul V , born Camillo Borghese, was Pope [i] from May 16 [i], 1605 [i] until his death. ... 

. In the On the new star Kepler explicated the meaning of the new star of 1604 as the conversion of America Americas

he Americas are the lands of the Western hemisphere [i] or New World [i] consisting o ... 

, downfall of Islam Islam

Islam is a monotheistic [i] religion [i] based upon the Qur'an [i], which adherents believe w ... 

 and return of Christ. The De cometis libelli tres is also replete with astrological Astrology

Astrology is a group of system [i]s, tradition [i]s, and belief [i]s in which knowledge of the relative ... 

 predictions.

Kepler on God

"I was merely thinking God's thoughts after him. Since we astronomers are priests of the highest God in regard to the book of nature," wrote Kepler, "it benefits us to be thoughtful, not of the glory of our minds, but rather, above all else, of the glory of God."

Writings by Kepler


  • Mysterium Cosmographicum
  • De Fundamentis Astrologiae Certioribus
  • Astronomiae Pars Optica
  • De Stella nova in pede Serpentarii
  • Astronomia nova
  • Dioptrice
  • Nova stereometria doliorum vinariorum
  • Epitome astronomiae Copernicanae
  • Harmonice Mundi
  • Tabulae Rudolphinae
  • Somnium Somnium

    Somnium is an album by the American [i] ambient [i] musician Robert Rich [i] ... 

    - considered the first precursor of science fiction Science fiction

    Science fiction is a popular genre of fiction in which the narrative world differs from our own present... 

    .

References

  • Peter Barker and Bernard R. Goldstein: "Theological Foundations of Kepler's Astronomy". Osiris, Volume 16: Science in Theistic Contexts. University of Chicago Press, 2001.


  • Max Caspar: Kepler; transl. and ed. by C. Doris Hellman; with a new introduction and references by Owen Gingerich; bibliographic citations by Owen Gingerich and Alain Segonds. New York: Dover, 1993 ISBN 0-486-67605-6


  • James A. Connor: Kepler's Witch: An Astronomer's Discovery of Cosmic Order Amid Religious War, Political Intrigue, and the Heresy Trial of His Mother. HarperSanFrancisco, 2004 ISBN 0-06-052255-0


  • J.V. Field: Kepler's geometrical cosmology. Chicago: Chicago University Press, 1988 ISBN 0-226-24823-2


  • Owen Gingerich: The eye of heaven: Ptolemy, Copernicus, Kepler. New York: American Institute of Physics, 1993 ISBN 0-88318-863-5


  • Kitty Ferguson: The nobleman and his housedog: Tycho Brahe and Johannes Kepler: the strange partnership that revolutionized science. London : Review, 2002 ISBN 0-747270-22-8


  • Arthur Koestler Arthur Koestler

    Arthur Koestler was a Hungarian [i] polymath [i] who became a naturalized British [i]... 

    : The Sleepwalkers: A History of Man's Changing Vision of the Universe. . ISBN 0-140-19246-8


  • John Lear: Kepler's Dream. Berkeley: University of California Press, 1965.


  • Bruce Stephenson: Kepler's physical astronomy. New York: Springer, 1987 ISBN 0-387-96541-6

Kepler in fiction


... 

: Kepler: a novel. London: Secker & Warburg, 1981 ISBN 0-436-03264-3 . Also published: Boston, MA:Godine, 1983 ISBN 0-87923-438-5. Draws heavily on Koestler's account of Kepler in The Sleepwalkers.

Named in Kepler's honor


  • Kepler Space Observatory Kepler Mission

    The Kepler Mission is a space observatory being developed by NASA [i] that will search for extrasolar planet [i] ... 

    , a solar-orbiting, planet-hunting telescope due to be launched by NASA NASA

    The National Aeronautics and Space Administration is an agency of the United States Government [i], res ... 

     in 2008.
  • The Kepler Solids Kepler-Poinsot solid

    A Kepler-Poinsot solid is a regular non-convex polyhedron [i], all the faces of which are identical regu ... 

    , a set of geometrical constructions, two of which were described by him.
  • Kepler's Star SN 1604

    Supernova 1604, also known as Kepler's Supernova or Kepler's Star, was a supernova [i] in th ... 

    , Supernova 1604, which he observed and described.
  • Kepler conjecture about sphere packing Sphere packing

    In mathematics [i], sphere packing problems are problems concerning arrangements of non-overlapping iden ... 

    , proved true 400 years later.
  • Kepler, a crater on the moon
  • Kepler, a crater on Mars
  • 1134 Kepler is an asteroid Asteroid

    Asteroid, minor planet, and planetoid are synonyms, and are used to indicate a diverse group of small ce... 

    .
  • In 1975, nine years after its founding, the College for Social and Economic Sciences Linz was renamed Johannes Kepler University Linz in honor of Johannes Kepler, since he wrote his magnum opus Harmonice Mundi in Linz.
  • Keplerstraße in Hanau near Frankfurt am Main

External links

  • Harmonices mundi in fulltext facsimile; in Latin Latin

    Latin is an ancient Indo-European language [i] originally spoken in Latium [i], ... 

  • Full text of by Walter W. Bryant, from Project Gutenberg Project Gutenberg

    Project Gutenberg is a volunteer effort to digitize, archive, and distribute cultural works.... 

  • by Nick Kollerstrom