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Johannes Kepler

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Johannes Kepler (December 27, 1571 - November 15, 1630), was a key figure in the Scientific revolution. He was German astrologer, astronomer, and mathematician; best known for his laws of planetary motion.

Kepler was a professor of mathematics at the University of Graz, court mathematician to Emperor Rudolf II, and court astrologer to General Wallenstein. Early in his career, Kepler was an assistant of Tycho Brahe's. Kepler's career coincided with that of Galileo Galilei.

He could reasonably be considered a transition figure between Renaissance and the Baroque period. He is sometimes referred to as “the first theoretical astrophysicis.” Carl Sagan also refers to him as the last scientific astrologer. His genius for math made his charts effective film flam.

Empiricism

“Look at the world, but don't experiment!,” such was the view of the natural philosophers before the scientific revolution. Nature, it was thought, should be looked at as it worked on its own. If one did an experiment, one was putting nature in unnatural circumstances, and hence the results of an experiment would not agree with the true way nature worked.

Under the influence of philosophers like Francis Bacon, an empirical tradition was developed in the 17th century. The Aristotelian belief of natural and artificial circumstances was abandoned, and a research tradition of systematic experimentation was slowly accepted throughout the scientific community. At the end of the scientific revolution the organic, quantitative world of book-reading philosophers had been changed into a mechanical, mathematical world to be known through experimental research. Though it is certainly not true that Newtonian science was like modern science in all respects, it closely resembled ours in many ways - much more so than the Aristotelian science of a century earlier.

Kick starting Cosmology, Thomas Digges modifies the Copernican system by removing its outer edge and replacing the edge with a star-filled unbounded space. Kepler with Tycho Brahe and Galileo Galilei could be considered the Baroque's first attempt at turning perpetatic Aristotelian philosophers into scientists. Kepler had more diverse interests and was quite interested in biology. Some credit him with the first scientific statement of a Gaia philosophy.

From the point of view of Quicksilver and other fictional universes, Kepler is a useful figure for a number of reasons:

  1. He illustrates a tension of the Baroque age - working for power figures in politics, who do not see a point in science for its own sake yet. They see it as a way to make toys and do soothsaying, but not as a way to make better weapons or buildings (the late Baroque and Enlightenment attitude)
  2. John Banville wrote an excellent fictional biography, Kepler: A novel, which explores among other things his relations with Tycho Brahe.
  3. Kepler's mother was accused of witchcraft
  4. Kepler's sacred geometry of the spheres, which he discarded for the elliptic orbits, is a good representation of the shift from earlier magical thinking to modern scientific models - it may be the best example of that transition. (see Kepler Solids)
  5. He was the very first person to say —— (according to Lewis Thomas) that the entire Earth was one giant living round cell —— the thesis of very much later Gaia philosophy.

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Johannes Kepler

From Wikipedia, the free encyclopedia.

Kepler focused on mathematics because his acuity of vision was poor. He was not as eagle-eyed as Tycho Brahe. Though it seems he was every bit as proud.

Some events of Kepler's life * December 27, 1571 born at Weil-der-Stadt * Comet of 1577 "I...was taken by my mother to a high place to look at it." (age six) * Lunar eclipse of 1580 "I was called outdoors... It appeared quite red." (age nine) * Graduates from University of Tübingen (1591 ) and pursues graduate study in theology * April 1594 Kepler takes mathematics faculty position at Gratz in Austria * April 1597 Kepler marries Barbara Muehleck. She died in 1611 survived by two children. * December 1599 Tycho Brahe writes inviting Kepler to assist him at Benatek outside Prague * November 1601 Kepler appointed imperial mathematician to the Hapsburg Emperor, after Tycho's death * October 1604 observes the supernova called Kepler's Star * January 1612 Emperor dies and Kepler takes post of provincial mathematian in Linz * May 15, 1618 Kepler discovers the distance-cubed-over-time-squared (or 'third') law of planetary motion (he first made the discovery on March 8 but rejected the idea for a while) * August 1620 Katherine, Kepler's mother, arrested in Leonburg as a witch; imprisoned for 14 months * October 1621 Katherine released after failure to convict; threatened with torture but refused to confess * November 15, 1630 in Ratisbon, Kepler dies of a fever

Scientific work

Like previous astronomers, Kepler initially believed that celestial objects moved in perfect circles. These models were consistent with observations and with the Platonic idea that the sphere was the perfect shape. After spending twenty years doing calculations with Tycho Brahe's data, Kepler concluded that this model of planetary motion was inconsistent with the data of Tycho Brahe. Using Tycho's data, Kepler was able to formulate Kepler's Laws of Planetary Motion in which planets move in ellipses, not circles.

Kepler discovered the three laws of planetary motion while trying to achieve the Pythagorean purpose of finding the harmony of the celestial spheres. In his cosmovision, it was not a coincidence that the number of perfect polyhedra was one less than the number of known planets. Having embraced the Copernican system, he set out to prove that the distances from the planets to the sun where given by spheres inside perfect polyhedra inside spheres. He thereby identified the five platonic solids with the five intervals between the six known planets - Mercury, Venus, Earth, Mars, Jupiter, Saturn and the five classical elements.

In 1596 Kepler published The Cosmic Mystery. 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 remains six bodies, the sphere and the five regular polyhedra. To the sphere 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, then the Pyramid, and finally the Dodecahedron. To the second group belongs, first, the Octahedron, and second, the Icosahedron. 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 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.

Supernova 1604, also known as Kepler's Supernova or Kepler's Star, was a supernova in the Milky Way, in the constellation Ophiuchus. As of this writing, it is the last supernova to have been observed in our own galaxy, occurring at approximately 6 kiloparsecs from Earth. A "naked-eye" supernova, it was brighter at its peak than any other star in the night sky, with apparent magnitude -2.5.

Since 6 kiloparsecs is ca. 20,000 light-years the cosmic event itself happened ca. 18,000 BCE.

The supernova was first observed on October 9, 1604. The German astronomer Johannes Kepler first saw it on October 17, but he studied it so extensively that the supernova was subsequently named after him. His book on the subject was entitled De Stella nova in pede Serpentarii (On the new star in Ophiuchus's foot).

It was the second supernova to be observed in a generation (after that seen by Tycho Brahe in Cassiopeia in 1572 ). No further supernovae have since been observed with certainty in the Milky Way, though others outside our galaxy have been seen.

The supernova remnant resulting from this supernova is considered to be one of the "prototypical" objects of its kind, and is still an object of much study in astronomy.

In his 1619 book, Harmonice Mundi, as well as the treatise Misterium Cosmographicum, he also made an association between the Platonic solids with the classical conception of the elements: The tetrahedron was the form of fire, the octahedron was that of air, the cube was earth, the icosahedron was water, and the dodecahedron was the cosmos as a whole or ether. There is some evidence this association was of ancient origin, as Plato relates 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 there were other rewards. Since he was the first to recognize the non-convex regular solids (such as the stellated dodecahedrons), they are named Kepler solids in his honor.

His most significant achievements came from the realization that the orbits of the planets were ellipses, not circles. 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 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, and which emanated from the sun. Although he did not discover gravity, he seems to have attempted to describe the first empirical example of a universal law, to explain the behavior of both earthly and heavenly bodies.

Kepler also made fundamental investigations into combinatorics, geometrical optimization, and natural phenomena such as snowflakes, always with an emphasis on form and design. He was also notable for defining antiprisms.

Only two years after his death in 1632, his grave was demolished by the Swedish army in the Thirty Years' War.

Writings by Kepler New Astronomy (1609 ) Somnium ("The Dream", 1634 )