# data[].attributes.body
"Johannes Kepler was a German astronomer, mathematician, and astrologer. He is a key figure in the 17th-century scientific revolution, best known for his laws of planetary motion"(wiki) 4i

# data[].attributes.body
The celatone was a device invented by Galileo Galilei to observe Jupiter's moons with the purpose of finding longitude on Earth

# data[].attributes.headline
He compiled a star catalog and the earliest surviving table of a trigonometric function and established mathematically that an object and its mirror image must make equal angles to a mirror.

# data[].attributes.subject
He compiled a star catalog and the earliest surviving table of a trigonometric function and established mathematically that an object and its mirror image must make equal angles to a mirror.

# data[].attributes.body
veronica : ) <3

# data[].attributes.body
Ptolemy was a mathematician, astronomer, geographer  who thought that the earth was the center of the univerce

raymond

# data[].attributes.body
Galileo fund a telescope which helped everybody to better observations. Then Galileo made observations which were based on never-before-possible observations. which showed mountains on our moon. soon after that Galileo made precise observations on Venus, Saturn, and even Neptune. Galileo then debated within science and what counts as good evidence.

# data[].attributes.headline
In the last book, he deals with a theory of refraction (the change in direction of light and other energy waves when they pass obliquely from a medium of one density into a medium of different density), and he discusses the refraction suffered by light from celestial bodies at various altitudes.

# data[].attributes.subject
In the last book, he deals with a theory of refraction (the change in direction of light and other energy waves when they pass obliquely from a medium of one density into a medium of different density), and he discusses the refraction suffered by light from celestial bodies at various altitudes.

# data[].attributes.body
Ronaldo

# data[].attributes.body
Ptolemy's astronomical work was enshrined in his great book He mathematike syntaxis ("The Mathematical Collection"), which eventually became known as Ho megas astronomos ("The Great Astronomer"). During the 9th century, however, Arab astronomers used the Greek superlative Megiste to refer to the book. When the definite article al was prefixed to the term, its title then became known as the Almagest, the name still used today.

The Almagest is divided into 13 books, each of which deals with certain astronomical concepts pertaining to stars and to objects in the solar system (the Earth and all other celestial bodies that revolve around the Sun). It was, no doubt, the encyclopaedic nature of the work that made the Almagest so useful to later astronomers and that gave the views contained in it so profound an influence. In essence, it is a synthesis of the results obtained by Greek astronomy; it is also the major source of knowledge about the work of Hipparchus, most probably the greatest astronomer of antiquity. Although it is often difficult to determine which findings in the book are those of Ptolemy and which are those of Hipparchus, Ptolemy did extend some of the work of Hipparchus through his own observations, apparently using somewhat similar instruments. For example, whereas Hipparchus had compiled a star catalog (the first of its kind) containing 850 stars, Ptolemy expanded the number in his own catalog to 1,022 stars.

On the motions of the Sun, Moon, and planets, Ptolemy again extended the observations and conclusions of Hipparchus--this time to formulate his geocentric theory, which is popularly known as the Ptolemaic system. (See Ptolemy's theory of the solar system.) In the first book of the Almagest, Ptolemy describes his geocentric system and gives various arguments to prove that, in its position at the center of the universe, the Earth must be immovable. Not least, he showed that if the Earth moved, as some earlier philosophers had suggested, then certain phenomena should in consequence be observed. In particular, Ptolemy argued that since all bodies fall to the center of the universe, the Earth must be fixed there at the center, otherwise falling objects would not be seen to drop toward the center of the Earth. Again, if the Earth rotated once every 24 hours, a body thrown vertically upward should not fall back to the same place, as it was seen to do. Ptolemy was able to demonstrate, however, that no contrary observations had ever been obtained. As a result of such arguments, the geocentric system became dogmatically asserted in Western Christendom until the 15th century, when it was supplanted by the heliocentric (Sun-centered) system of Nicolaus Copernicus (q.v.), a Polish astronomer.

The Christian Aristotelian cosmos, engraving from Peter Apian's Cosmographia, 1524

Ptolemy accepted the following order for celestial objects in the solar system: Earth (center), Moon, Mercury, Venus, Sun, Mars, Jupiter, and Saturn. He realized, as had Hipparchus, that the inequalities in the motions of these heavenly bodies necessitated either a system of deferents and epicycles or one of movable eccentrics (both systems devised by Apollonius of Perga, the Greek geometer of the 3rd century BC) in order to account for their movements in terms of uniform circular motion.

In the Ptolemaic system, deferents were large circles centered on the Earth, and epicycles were small circles whose centers moved around the circumferences of the deferents. The Sun, Moon, and planets moved around the circumference of their own epicycles. In the movable eccentric, there was one circle; this was centered on a point displaced from the Earth, with the planet moving around the circumference. These were mathematically equivalent schemes. Even with these, all observed planetary phenomena still could not be fully taken into account. Ptolemy therefore exhibited brilliant ingenuity by introducing still another concept. He supposed that the Earth was located a short distance from the center of the deferent for each planet and that the center of the planet's deferent and the epicycle described uniform circular motion around what he called the equant, which was an imaginary point that he placed on the diameter of the deferent but at a position opposite to that of the Earth from the center of the deferent--i.e., the center of the deferent was between the Earth and the equant. He further supposed that the distance from the Earth to the center of the deferent was equal to the distance from the center of the deferent to the equant. With this hypothesis, Ptolemy could better account for many observed planetary phenomena.

In the Ptolemaic system, the plane of the ecliptic is that of the Sun's apparent annual path among the stars. The planes of the deferents of the planets were believed to be inclined at small angles to the plane of the ecliptic, while the planes of their epicycles were inclined by equal amounts to those of the deferents, so that the planes of the epicycles would always parallel that of the ecliptic. The planes of the deferents of Mercury and Venus were assumed to oscillate above and below the plane of the ecliptic, and likewise the planes of their epicycles were thought to oscillate with respect to the planes of the deferents.
All this was necessary to explain retrograde motion, the apparent backwards track of the outer planets against the background of stars.

Although Ptolemy realized that the planets were much closer to the Earth than the "fixed" stars, he seems to have believed in the physical existence of crystalline spheres, to which the heavenly bodies were said to be attached. Outside the sphere of the fixed stars, Ptolemy proposed other spheres, ending with the primum mobile ("prime mover"), which provided the motive power for the remaining spheres that constituted his conception of the universe.
As a geometrician of the first order, Ptolemy performed important work in mathematics. He devised new geometrical proofs and theorems; and, in a book entitled Analemma (Greek Peri analemmatos; Latin De analemmate), he discussed the details of the projection of points on the celestial sphere (an imaginary sphere extending outward from the Earth for an infinite distance and on whose surface the objects in space appear to be located) onto three planes at right angles (90) to each other--the horizon, the meridian, and the prime vertical. In another book, the Planisphaerium, Ptolemy is concerned with stereographic projection--the delineation of the forms of solid bodies on a plane--and here he used the south celestial pole as his center of projection.

Ptolemy also prepared a calendar that gave, in addition to weather indications, the risings and settings of the stars in the morning and evening twilight. Other mathematical publications include a work, in two books, entitled Hypotheseis ton planomenon ("Planetary Hypothesis") and two separate geometrical works, one of which is concerned with proving that there cannot be more than three dimensions of space; the other contains an attempted proof for a postulate on parallel lines that had been devised by Euclid. According to one authority, Ptolemy wrote three books on mechanics; another authority, however, credits him with only one mechanical work, Peri ropon ("On Balancing").

Ptolemy's work on optical phenomena appeared in Optica, the original edition of which consisted of five books. In the last book, he deals with a theory of refraction (the change in direction of light and other energy waves when they pass obliquely from a medium of one density into a medium of different density), and he discusses the refraction suffered by light from celestial bodies at various altitudes. This is the first recorded attempt at a solution of this observational problem. Ptolemy also wrote a three-book treatise on music known as the Harmonica.

As a geographer, Ptolemy's reputation rests mainly on his Geographike hyphegesis (Guide to Geography), which was divided into eight books; it included information on how to construct maps and lists of places in Europe, Africa, and Asia tabulated according to latitude and longitude. There were, however, many errors in the Guide--e.g., the Equator was placed too far north, and the value used for the circumference of the Earth was nearly 30 percent less than a more accurate value that had already been determined--as well as some contradictions between the text and maps. Moreover, as a whole, the Guide cannot be considered "good geography"; it does not mention anything about the climate, natural products, inhabitants, or peculiar features of the countries with which it deals, and Ptolemy's treatment of the geographical importance of such factors as rivers and mountain ranges is careless and of little use.

In spite of its faults, the Guide is an important work from a historical point of view because, like the Almagest, it exerted a great influence on later generations. Christopher Columbus, for example, used it to strengthen his belief that Asia could be reached by travelling westward because Ptolemy had indicated that Asia extended much farther east than it actually does. Even as late as 1775, it was believed that the Indian Ocean was bounded by a southern continent, as Ptolemy had suggested; the return voyage from the Southern Hemisphere of Capt. James Cook in July of that year proved otherwise.

Excerpt from the Encyclopedia Britannica without permission.
Fuquan

# data[].attributes.body
German astronomer who discovered three major laws of planetary motion, conventionally designated as follows: (1) the planets move in elliptical orbits with the Sun at one focus; (2) the time necessary to traverse any arc of a planetary orbit is proportional to the area of the sector between the central body and that arc (the “area law”); and (3) there is an exact relationship between the squares of the planets’ periodic times and the cubes of the radii of their orbits (the “harmonic law”)

# data[].attributes.attachment_link.readable_text
What was Johannes Kepler's profession? When and how did it begin?

What was Johannes Kepler known for?

Who did Johannes Kepler influence?

Where was Johannes Kepler born?

How and where did Johannes Kepler die?

Johannes Kepler, (born December 27, 1571, Weil der Stadt, Württemberg [Germany]-died November 15, 1630, Regensburg), German astronomer who discovered three major laws of planetary motion, conventionally designated as follows: (1) the planets move in elliptical orbits with the Sun at one focus; (2) the time necessary to traverse any arc of a planetary orbit is proportional to the area of the sector between the central body and that arc (the "area law"); and (3) there is an exact relationship between the squares of the planets' periodic times and the cubes of their mean distances from the Sun (the "harmonic law"). Kepler himself did not call these discoveries "laws," as would become customary after Isaac Newton derived them from a new and quite different set of general physical principles. He regarded them as celestial harmonies that reflected God's design for the universe. Kepler's discoveries turned Nicolaus Copernicus's Sun-centred system into a dynamic universe, with the Sun actively pushing the planets around in noncircular orbits. And it was Kepler's notion of a physical astronomy that fixed a new problematic for other important 17th-century world-system builders, the most famous of whom was Newton.

Among Kepler's many other achievements, he provided a new and correct account of how vision occurs; he developed a novel explanation for the behaviour of light in the newly invented telescope; he discovered several new, semiregular polyhedrons; and he offered a new theoretical foundation for astrology while at the same time restricting the domain in which its predictions could be considered reliable. A list of his discoveries, however, fails to convey the fact that they constituted for Kepler part of a common edifice of knowledge. The matrix of theological, astrological, and physical ideas from which Kepler's scientific achievements emerged is unusual and fascinating in its own right. Yet, because of the highly original nature of Kepler's discoveries, it requires an act of intellectual empathy for moderns to understand how such lasting results could have evolved from such an apparently unlikely complex of ideas. Although Kepler's scientific work was centred first and foremost on astronomy, that subject as then understood-the study of the motions of the heavenly bodies-was classified as part of a wider subject of investigation called "the science of the stars." The science of the stars was regarded as a mixed science consisting of a mathematical and a physical component and bearing a kinship to other like disciplines, such as music (the study of ratios of tones) and optics (the study of light). It also was subdivided into theoretical and practical categories. Besides the theory of heavenly motions, one had the practical construction of planetary tables and instruments; similarly, the theoretical principles of astrology had a corresponding practical part that dealt with the making of annual astrological forecasts about individuals, cities, the human body, and the weather. Within this framework, Kepler made astronomy an integral part of natural philosophy, but he did so in an unprecedented way-in the process, making unique contributions to astronomy as well as to all its auxiliary disciplines.

# data[].attributes.attachment_link.title
Johannes Kepler | Biography, Discoveries, & Facts

# data[].attributes.attachment_link.description
Johannes Kepler, German astronomer who discovered three major laws of planetary motion. His discoveries turned Nicolaus Copernicus's Sun-centered system into a dynamic universe, with the Sun actively pushing the planets around in noncircular orbits. Learn more about Kepler's life and discoveries in this article.

# data[].attributes.headline
Ptolemy made contributions to astronomy, mathematics, geography, musical theory, and optics.

# data[].attributes.subject
Ptolemy made contributions to astronomy, mathematics, geography, musical theory, and optics.

# data[].attributes.body
veronica <3

# data[].attributes.headline
Ptolemy was an astronomer and mathematician. He believed that the Earth was the center of the Universe. ... In order to make his predictions true, he worked out that the planets must move in epicycles, smaller circles, and the Earth itself moved along an equant.

# data[].attributes.subject
Ptolemy was an astronomer and mathematician. He believed that the Earth was the center of the Universe. ... In order to make his predictions true, he worked out that the planets must move in epicycles, smaller circles, and the Earth itself moved along an equant.

# data[].attributes.body
Ronaldo

# data[].attributes.headline
Brooke O'Meany-Lucas                            Nicolaus Copernicus 1473-1543 

# data[].attributes.subject
Brooke O'Meany-Lucas                            Nicolaus Copernicus 1473-1543 

# data[].attributes.body
Nicolaus was born in the 1400's, and was a mathematician and astronomer in the Renaissance-era. He formulated a model of the solar system, with the Sun at its center rather than the Earth. This was likely done without he help from an earlier astronomer's ideas 18 centuries earlier. He published a book called "De revolutionibus orbium coelestium", that had his model within. This was a major contribution to the Copernican Revolution, and the Scientific Revolution.

# data[].attributes.headline
meliana: Galileo provided powerful support for the Copernican system with observations from his telescope.

# data[].attributes.subject
meliana: Galileo provided powerful support for the Copernican system with observations from his telescope.

# data[].attributes.body
Galileo did not invent the telescope, but he was the first to turn his telescope toward the sky to study the heavens systematically

# data[].attributes.body
Robert
Julian
Julia
Dayveion
Mateo

# data[].attributes.body
Jamie
Meliana
JuanPablo
Jacob
Analicia

# data[].attributes.body
Jacqueline
Giovanni
Gilberto
Lori
, Brooke

# data[].attributes.body
FuQuan,
Ronaldo,
Veronica,
Athalia,
Jamilet,
Raymond

# data[].attributes.body
Jose,
Alicia,
Sema'j,
Larry,
Ralph