Universe

Not so much a theory of the universe as a simple picture of the planet we call home, the flat-earth model proposed that Earth’s surface was level. Although everyday experience makes this seem a reasonable assumption, direct observation of nature shows the real world isn’t that simple. For instance, when a sailing ship heads into port, the first part that becomes visible is the crow’s-nest, followed by the sails, and then the bow of the ship. If the Earth were flat, the entire ship would come into view at once as soon as it came close enough to shore. The Greek philosopher Aristotle provided two more reasons why the Earth was round. First, he noted that Earth’s shadow always took a circular bite out of the moon during a lunar eclipse, which would only be possible with a spherical Earth. (If the Earth were a disk, its shadow would appear as an elongated ellipse at least during part of the eclipse.) Second, Aristotle knew that people who journeyed north saw the North Star ascend higher in the sky, while those heading south saw the North Star sink. On a flat Earth, the positions of the stars wouldn’t vary with a person’s location. Despite these arguments, which won over most of the world’s educated citizens, belief in a flat Earth persisted among many others. Not until explorers first circumnavigated the globe in the 16th century did those beliefs begin to die out. Ptolemy, the last of the great Greek astronomers of antiquity, developed an effective system for mapping the universe. Basing much of his theory on the work of his predecessor, Hipparchus, Ptolemy designed a geocentric, or Earth-centered, model that held sway for 1400 years. That Ptolemy could place Earth at the center of the universe and still predict the planets’ positions adequately was a testament to his ability as a mathematician. That he could do so while maintaining the Greek belief that the heavens were perfect—and thus that each planet moved along a circular orbit at a constant speed—is nothing short of remarkable. Copernicus made a great leap forward by realizing that the motions of the planets could be explained by placing the Sun at the center of the universe instead of Earth. In his view, Earth was simply one of many planets orbiting the Sun, and the daily motion of the stars and planets were just a reflection of Earth spinning on its axis. Although the Greek astronomer Aristarchus developed the same hypothesis more than 1500 years earlier, Copernicus was the first person to argue its merits in modern times. Despite the basic truth of his model, Copernicus did not prove that Earth moved around the Sun. That was left for later astronomers. The first direct evidence came from Newton’s laws of motion, which say that when objects orbit one another, the lighter object moves more than the heavier one. Because the Sun has about 330,000 times more mass than Earth, our planet must be doing almost all the moving. A direct observation of Earth’s motion came in 1838 when the German astronomer Friedrich Bessel measured the tiny displacement, or parallax, of a nearby star relative to the more distant stars. This minuscule displacement reflects our planet’s changing vantage point as we orbit the Sun during the year. How did the universe really begin? Most astronomers would say that the debate is now over: The universe started with a giant explosion, called the Big Bang. The big-bang theory got its start with the observations by Edwin Hubble that showed the universe to be expanding. If you imagine the history of the universe as a long-running movie, what happens when you show the movie in reverse? All the galaxies would move closer and closer together, until eventually they all get crushed together into one massive yet tiny sphere. It was just this sort of thinking that led to the concept of the Big Bang. The Big Bang marks the instant at which the universe began, when space and time came into existence and all the matter in the cosmos started to expand. Amazingly, theorists have deduced the history of the universe dating back to just 1043 second (10 million trillion trillion trillionths of a second) after the Big Bang. Before this time all four fundamental forces—gravity, electromagnetism, and the strong and weak nuclear forces—were unified, but physicists have yet to develop a workable theory that can describe these conditions. During the first second or so of the universe, protons, neutrons, and electrons—the building blocks of atoms—formed when photons collided and converted their energy into mass, and the four forces split into their separate identities. The temperature of the universe also cooled during this time, from about 1032 (100 million trillion trillion) degrees to 10 billion degrees. Approximately three minutes after the Big Bang, when the temperature fell to a cool one billion degrees, protons and neutrons combined to form the nuclei of a few heavier elements, most notably helium. The next major step didn’t take place until roughly 300,000 years after the Big Bang, when the universe had cooled to a not-quite comfortable 3000 degrees. At this temperature, electrons could combine with atomic nuclei to form neutral atoms. With no free electrons left to scatter photons of light, the universe became transparent to radiation. (It is this light that we see today as the cosmic background radiation.) Stars and galaxies began to form about one billion years following the Big Bang, and since then the universe has simply continued to grow larger and cooler, creating conditions conducive to life. Three excellent reasons exist for believing in the big-bang theory. First, and most obvious, the universe is expanding. Second, the theory predicts that 25 percent of the total mass of the universe should be the helium that formed during the first few minutes, an amount that agrees with observations. Finally, and most convincing, is the presence of the cosmic background radiation. The big-bang theory predicted this remnant radiation, which now glows at a temperature just 3 degrees above absolute zero, well before radio astronomers chanced upon it. Friedmann made two simple assumptions about the universe: that when viewed at large enough scales, it appears the same both in every direction and from every location. From these assumptions (called the cosmological principle) and Einstein’s equations, he developed the first model of a universe in motion. The Friedmann universe begins with a Big Bang and continues expanding for untold billions of years—that’s the stage we’re in now. But after a long enough period of time, the mutual gravitational attraction of all the matter slows the expansion to a stop. The universe then starts to fall in on itself, replaying the expansion in reverse. Eventually all the matter collapses back into a singularity, in what physicist John Wheeler likes to call the “Big Crunch.” Gravitational attraction is a fundamental property of matter that exists throughout the known universe. Physicists identify gravity as one of the four types of forces in the universe. The others are the strong and weak nuclear forces and the electromagnetic force. More than 300 years ago, the great English scientist Sir Isaac Newton published the important generalization that mathematically describes this universal force of gravity. Newton was the first to realize that gravity extends well beyond the boundaries of Earth. Newton's realization was based on the first of three laws he had formulated to describe the motion of objects. Part of Newton's first law, the Law of Inertia, states that objects in motion travel in a straight line at a constant velocity unless they are acted upon by a net force. According to this law, the planets in space should travel in straight lines. However, as early as the time of Aristotle, the planets were known to travel on curved paths. Newton reasoned that the circular motions of the planets are the result of a net force acting upon each of them. That force, he concluded, is the same force that causes an apple to fall to the ground--gravity. Newton's experimental research into the force of gravity resulted in his elegant mathematical statement that is known today as the Law of Universal Gravitation. According to Newton, every mass in the universe attracts every other mass. The attractive force between any two objects is directly proportional to the product of the two masses being measured and inversely proportional to the square of the distance separating them. If we let F represent this force, r the distance between the centers of the masses, and m1 and m2 the magnitude of the two masses, the relationship stated can be written symbolically as: is defined mathematically to mean is proportional to.) From this relationship, we can see that the greater the masses of the attracting objects, the greater the force of attraction between them. We can also see that the farther apart the objects are from each other, the less the attraction. It is important to note the inverse square relationship with respect to distance. In other words, if the distance between the objects is doubled, the attraction between them is diminished by a factor of four, and if the distance is tripled, the attraction is only one-ninth as much. Newton's Law of Universal Gravitation was later quantified by eighteenth-century English physicist Henry Cavendish who actually measured the gravitational force between two one-kilogram masses separated by a distance of one meter. This attraction was an extremely weak force, but its determination permitted the proportional relationship of Newton's law to be converted into an equation. This measurement yielded the universal gravitational constant or G.

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Tycho Brahe

Tycho Brahe Tyge (Latinized as Tycho) Brahe was born on 14 December 1546 in Skane, then in Denmark, now in Sweden. He was the eldest son of Otto Brahe and Beatte Bille, both from families in the high nobility of Denmark. He was brought up by his paternal uncle Jörgen Brahe and became his heir. He attended the universities of Copenhagen and Leipzig, and then traveled through the German region, studying further at the universities of Wittenberg, Rostock, and Basel. During this period his interest in alchemy and astronomy was aroused, and he bought several astronomical instruments. In 1572 Tycho observed the new star in Cassiopeia and published a brief tract about it the following year. In 1574 he gave a course of lectures on astronomy at the University of Copenhagen. He was now convinced that the improvement of astronomy hinged on accurate observations. After another tour of Germany, where he visited astronomers, Tycho accepted an offer from the King Frederick II to fund an observatory. He was given the little island of Hven in the Sont near Copenhagen, and there he built his observatory, Uraniburg, which became the finest observatory in Europe. Tycho designed and built new instruments, calibrated them, and instituted nightly observations. He also ran his own printing press. The observatory was visited by many scholars, and Tycho trained a generation of young astronomers there in the art of observing. After a falling out with King Christian IV, Tycho packed up his instruments and books in 1597 and left Denmark. After traveling several years, he settled in Prague in 1599 as the Imperial Mathematician at the court of Emperor Rudolph II. He died there in 1601. His instruments were stored and eventually lost. Tycho Brahe's contributions to astronomy were enormous. He not only designed and built instruments, he also calibrated them and checked their accuracy periodically. He thus revolutionized astronomical instrumentation. He also changed observational practice profoundly. Whereas earlier astronomers had been content to observe the positions of planets and the Moon at certain important points of their orbits. Tycho and his cast of assistants observed these bodies throughout their orbits. As a result, a number of orbital anomalies never before noticed were made explicit by Tycho. Without these complete series of observations of unprecedented accuracy, Kepler could not have discovered that planets move in elliptical orbits. Tycho was also the first astronomer to make corrections for atmospheric refraction*. In general, whereas previous astronomers made observations accurate to perhaps 15 arc minutes, those of Tycho were accurate to perhaps 2 arc minutes, and it has been shown that his best observations were accurate to about half an arc minute. Tycho's observations of the new star of 1572 and comet of 1577, and his publications on these phenomena, were instrumental in establishing the fact that these bodies were above the Moon and that therefore the heavens were not immutable as Aristotle had argued and philosophers still believed. The heavens were changeable and therefore the Aristotelian division between the heavenly and earthly regions came under attack (see, for instance, Galileo's Dialogue) and was eventually dropped. Further, if comets were in the heavens, they moved through the heavens. Up to now it had been believed that planets were carried on material spheres (spherical shells) that fit tightly around each other. Tycho's observations showed that this arrangement was impossible because comets moved through these spheres. Celestial spheres faded out of existence between 1575 and 1625. Tycho developed a system that combined the best of both worlds. He kept the Earth in the center of the universe, so that he could retain Aristotelian physics The Moon and Sun revolved about the Earth, and the shell of the fixed stars was centered on the Earth. But Mercury, Venus, Mars, Jupiter, and Saturn revolved about the Sun. He put the (circular) path of the comet of 1577 between Venus and Mars. This Tychonic world system became popular early in the seventeenth century among those who felt forced to reject the Ptolemaic arrangement of the planets (in which the Earth was the center of all motions) but who, for various reasons, could not accept the Copernican alternative. Tycho's major works include De Nova et Nullius Aevi Memoria Prius Visa Stella (On the New and Never Previously Seen Star) (Copenhagen, 1573); De Mundi Aetherei Recentioribus Phaenomenis (Concerning the New Phenomena in the Ethereal World) (Uraniburg, 1588); Astronomiae Instauratae Mechanica (Instruments for the Restored Astronomy) (Wandsbeck, 1598; English tr. Copenhagen, 1946); Astronomiae Instauratae Progymnasmata (Introductory Exercises Toward a Restored Astronomy) (Prague 1602). His observations were not published during his lifetime.

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The Stars And Galaxies

MEGAN JACKSON MS. KEYS SCIENCE DECEMBER 5,2000 THE STARS AND GALAXIES Have you ever looked up at the sky and wondered what are those bright and shiny things up there. Stars: a natural luminious body visible in the sky especially at night. A self-luminious gaseous celestial body ofgreat mass which produces energy by means of nuclear fusion reactions, whose shape is usually spheroidal, and whose size may be as small as the earth or larger than the earth’s orbit. Galaxies: Any of the very large groups of stars and associated matter that are found throughout the universe. In 1802, William Wollaston noted that the spectrum of sunlight did not appear to be a continious band of colors, but rather had a series of dark lines superimposed on it. Wollaston attributed the lines to natural boundaries between colors. Joseph Fraunhofer made a more careful set of observations of the solar spectrum in 1814 and found some 600 dark lines, and he specifically measured the wavelenght of 324 of them. Many of the Fraunhofer lines in the solar spectrum retain the notations he created to designate them. In 1864, Sir William Huggins matched some of these dark lines in the spectra from other stars with terrestrial substances, demonstrating that the stars are made of the same materials of everyday material rather than exotic substances. This paved the way for modern spectroscopy. Since even before the discovery of the spectra, scientists had tried to find ways to catergorize stars. By observing spectra , astronomers realized that the large numbers of stars exhibit a small number of distinct patterns in their spectral lines. Classification by the spectral features quickly proved to be a powerful tool for understanding stars. The current spectral classification scheme was developed at Harvard Observatory in the early 20th century. Work was begun by Henry Draper who photographed the first spectrum of Vega in 1872. After his death, his wife donated the equipment and a sum of money to the Observatory to continue his work. The bulk of classification work was done by Annie Jump Cannon from 1918 to 1924. The original scheme used capital letters running alphabetically, but the subsequent revisions have reduced this as stellar evolution and typing has become better understood. The work was published in the Henry Draper Catalog and Henry Draper Extension which contained spectra of 225,000 stars down to ninth magnitude. The scheme is based on lines which are mainly sensitiveto stellar surface tempertures rather than actual composition differences,gravity, or luminosity. Inportant lines

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The Solar System

Assignment 1: The Solar System The solar system consists of the Sun; the nine planets, 67 satellites of the planets and a large number of small bodies (comets and asteroids). The inner solar system contains the Sun, Mercury, Venus, Earth and Mars: The planets of the outer solar system are Jupiter, Saturn, Uranus, Neptune and Pluto: The orbits of the planets are ellipses with the Sun at one focus, though all except Mercury and Pluto are very nearly circular. The orbits of the planets are all more or less in the same plane (called the ecliptic and defined by the plane of the Earth's orbit). The ecliptic is inclined only 7 degrees from the plane of the Sun's equator. Pluto's orbit deviates the most from the plane of the ecliptic with an inclination of 17 degrees. Below you see a diagram that show some relative information about most of the objects in our Solar System: Diameter (km) Moons Surface temp. Surface gravity Axial inclination Axial rotation The Sun 1 390 000 - 5800c - - 25 - 36 days Mercury 4 878 None 350c / -170c 0.38 0 58 days Venus 12 104 None 480c 0.9 178 243 days The Earth 12 756 1 20c 1 23.4 23h 56m Mars 6 787 None -23c 0.38 24 24h 37m Jupiter N/A 16 -150c 2.64 3.1 9h 50m Saturn 199 300 18 -180c 1.2 26.7 10h 39m Uranus 51 800 15 -210c 1.2 98 17h 10m Neptune 49 500 8 -220c 1.2 29.5 18h 24m Pluto 2 320 1 N/A 0.04 50 178 years The Moon 3 474 - 107c / -153c 0.17 1.5 27 days The Sun The sun is the most important part of our solar system. It is the biggest object and does have about 98% of the whole mass of the solar system. About 1,3 billion earths would fit inside the sun. The sun travels around the galaxy together with planets and other objects bound to it by gravitational forces. The largest of the bodies we call planets, most of which are in turn are orbited by smaller moons or satellites. These objects, together with many lesser masses, are known as the Solar system. The Sun is just a star, one of a hundred billion inhabiting our galaxy alone. Being a star the Sun is an example of the fundamental building blocks of our universe. It formed, 4.5 billion years ago, as the nucleus of a cloud of gas which was collapsing under its own gravitational attraction. At formation, hydrogen was the most abundant gas, as elsewhere in the universe, and accounted for three quarters of the Sun's original material. This will changes as the hydrogen is burned, and within the very central regions virtually all the hydrogen has been converted to helium. The outer regions have not yet taken part in hydrogen burning. Astronomers have measured the chemical composition of the Sun, and can thus estimate that of the initial solar nebula from which the sun and planets formed. In addition to 78 percent by weight of hydrogen, they find 20 percent to be helium, while only 2 percent remains for other elements such as oxygen, carbon, nitrogen, and iron. Later, as its hydrogen becomes depleted, it will evolve into a giant red star, swelling to engulf the earth and the inner planets. The remnant Sun will fade gradually to oblivion, passing through the white dwarf stage on its way. Mercury Mercury is named after the messenger of the Roman gods. It is the smallest of the inner planets and the second smallest in the whole Solar System. It has a very weak magnetic field and - being the closest planet to the Sun - has only a very thin atmosphere of helium captured from the solar wind. The surface of Mercury is very much like the Moon's - with craters, mountains and valleys. Since there is no form of atmosphere, life on Mercury is impossible. Nor will there be any manned flights in the forseeable future. However, there will be new unmanned probes sent out, if only to complete the map of the surface. Although Mercury has only a third the diameter of Earth, its density is about the same. This suggests that 65 to 70 percent of Mercury's weight is made up of a heavy material, probably iron. This is concentrated in Mercury's large core. The outer layer is made of sillicate rock similar to the Earth's mantle. Venus Venus is named after the Roman goddess of love. It is the second planet from the Sun and the brightest object in the sky other than the Sun and the Moon. It was once believed that life could exist in Venus but that has been proved wrong by various probes. In fact, Venus has the most hostile environment in the entire Solar System. The surface temperature is fiercely hot and the atmospheric pressure is crushing. One of the more apparent things that separate Venus from all the other planets in our solar system is that it rotates from east to west (all the other planets rotate from west to east). Because of this, Venus is said to be almost upside down. Conditions may have been better in the past. In the early stages of the Solar System, the Sun was not as bright as it is now and so Venus and the Earth would have formed similarly. When the Sun became brighter, the Earth was far enough away to escape serious damage but Venus was not. The surface temperature rose and the oceans dried up. Earth The Earth, the third planet (rock) from the Sun, is the largest of the inner planets and also has the highest density. It is the only planet in the Solar System to be covered largely with water, the only planet with an atmosphere made up chiefly of nitrogen and oxygen and the only body that has a temperature suitable for life of the type that we know. It is also the only inner planet with a large moon - Mercury and Venus have none and the Martian moons are small. If the conditions on the Earth changed even slightly, the life as we know it could die out. The Earth's rotation period is not constant. It is slowly lengthening due to tidal friction between the oceans and the sea floor. This is caused by the influence of the Moon. Our Moon The Moon has fascinated mankind throughout the ages. By simply viewing with the naked eye, one can discern two major types of terrain: relatively bright highlands and darker plains. Current knowledge of the Moon is greater than for any other solar system object except Earth. This lends to a greater understanding of geologic processes and further appreciation of the complexity of terrestrial planets. The relatively bright, heavily cratered highlands are called terrae. The craters and basins in the highlands are formed by meteorite. Mars Mars is the fourth planet from the Sun and the seventh largest. Mars is sometimes referred to as the Red Planet. The name of the month March derives from Mars. Mars has been known since prehistoric times. Except for Earth, Mars has the most highly varied and interesting terrain of any of the terrestrial planets. One being Olympus Mons, the largest mountain in the Solar System rising 24 km (78,000 ft.) above the surrounding plain. Like Mercury and the Moon, Mars appears to lack active plate tectonics at present; there is no evidence of recent horizontal motion of the surface such as the folded mountains so common on Earth. Jupiter Jupiter is named after the king of the Roman gods. It is the largest planet in the Solar System, the fifth planet from the Sun and the first of the outer planets Jupiter has had a dominant effect on a large part of the Solar System. It is likely that Jupiter's huge gravity has prevented a planet from forming in the area now occupied by the Asteroid Belt. Jupiter has a magnetic field 20,000 times stronger than that of the Earth's, having a devastating effect on its moons. Saturn Saturn is the sixth planet from the Sun and the second largest: In Roman mythology, Saturn is the god of agriculture and has been known since prehistoric times. Galileo was the first to observe it with a telescope in 1610; he noted its odd appearance but was confused by it. Early observations of Saturn were complicated by the fact that the Earth passes through the plane of Saturn's rings every few years as Saturn moves in its orbit Like Jupiter, Saturn is about 75% hydrogen and 25% helium with traces of water, methane, ammonia and rock, similar to the composition of the primordial Solar Nebula from which the solar system was formed. Uranus Uranus is the forth largest planet in the Solar System and the seventh from the Sun. Named after the father of Saturn, Uranus is a blue-green colour due to the methane in its atmosphere. Its magnetic axis is at 60 degrees to its axis of rotation. The unusual axial tilt may have been caused by a collision by a large body early in Uranus' life. Scientists must await a new space mission. Uranus is composed primarily of rock and various ices, with only about 15% hydrogen and a little helium (in contrast to Jupiter and Saturn which are mostly hydrogen). Neptune Neptune - named after the Roman god of the sea - was discovered using mathematic calculations based on the orbit of Uranus. It is the third largest planet in the Solar System and is usually the second last planet in distance. Because of Pluto's eccentic orbit, Neptune is the last planet for 20 years every 247 years. Neptune was the last planet until recently, when Pluto past it with its orbit and became the last planet again. Pluto Pluto was discovered on February 18, 1930, making it the last planet found in our Solar System. Pluto is usually farther from the Sun then any of the nine planets. Ground-based observations indicate that Pluto's surface is covered with methane ice and that there is a thin atmosphere that might freeze and fall to the surface as the planet moves away from the Sun. Pluto has one moon - Charon - its surface composition seems to be different from Pluto's. The moon appears to be covered with water-ice rather than methane ice. Its orbit is gravitationally locked with Pluto, so both bodies always keep the same hemisphere facing each other. Asteroids Asteroids are rocky and metallic objects that orbit the Sun but are too small to be considered planets. They are known as minor planets. Asteroids range in size from Ceres, which has a diameter of about 1000 km, down to the size of pebbles. Sixteen asteroids have a diameter of 240 km or greater. They have been found inside Earth's orbit to beyond Saturn's orbit. Most, however, are contained within a main belt that exists between the orbits of Mars and Jupiter. Asteroids are material left over from the formation of the solar system. One theory suggests that they are the remains of a planet that was destroyed in a massive collision long ago. Meteors and Meteorites The term meteor comes from the Greek “meteoron”, meaning phenomenon in the sky. A meteoroid is matter revolving around the sun or any object in interplanetary space that is too small to be called an asteroid or a comet. A meteorite is a meteoroid that reaches the surface of the Earth without being completely vaporized. Meteorites have proven difficult to classify, but the three broadest groupings are stony, stony iron, and iron. The most common meteorites are chondrites, which are stony meteorites. Radiometric dating of chondrites has placed them at the age of 4.55 billion years, which is the approximate age of the solar system. Comets Comets are small, fragile, irregularly shaped bodies composed of a mixture of non-volatile grains and frozen gases. They have highly elliptical orbits that bring them very close to the Sun and swing them deeply into space, often beyond the orbit of Pluto. Comet structures are diverse and very dynamic, but they all develop a surrounding cloud of diffuse material, called a coma, that usually grows in size and brightness as the comet approaches the Sun. As comets approach the Sun they develop enormous tails of luminous material that extend for millions of kilometers from the head, away from the Sun. History Traditionally histories of Astronomy usually begin with the Greeks. The Greek philosopher Aristotle held that the earth is fixed at the center of the universe while Ptolemy based a mathematical model of the moving planets in our Solar System. Nicolaus Copernicus, in 1543, published his hypothesis that the sun is the center of the universe but since the teaching of Aristotle had been adopted by the church his view was seen as unbelievable. 1609 A.D. Five years after the appearance of the great supernova of 1604, Galileo builds his first telescope. He sees the moons of Jupiter, Saturn's rings, the phases of Venus, and the stars in the Milky Way. He publishes the news the following year in The Starry Messinger. 1665 A.D. At the age of 23, young Isaac Newton realizes that gravitational force accounts for falling bodies on earth as well as the motion of the moon and the planets in orbit. This is a revolutionary step in the history of thought, as it extends the influence of earthly behavior to the realm of the heavens. One set of laws, discovered and tested on our planet, will be seen to govern the entire universe. 1905 A.D. The first of his many seminal contributions to twentieth century science, relativity recognizes the speed of light as the absolute speed limit in the universe and, as such, unites the previously separate concepts of space and time into a unified spacetime. Eleven years later, his General Theory of Relativity replaces Newton's model of gravity with one in which the gravitational force is interpreted as the response of bodies to distortions in spacetime which matter itself creates.

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The Moon

The Moon is the only natural satellite of Earth: orbit: 384,400 km from Earth diameter: 3476 km mass: 7.35e22 kg Called Luna by the Romans, Selene and Artemis by the Greeks, and many other names in other mythologies. The Moon, of course, has been known since prehistoric times. It is the second brightest object in the sky after the Sun. As the Moon orbits around the Earth once per month, the angle between the Earth, the Moon and the Sun changes; we see this as the cycle of the Moon's phases. The time between successive new moons is 29.5 days (709 hours), slightly different from the Moon's orbital period (measured against the stars) since the Earth moves a significant distance in its orbit around the Sun in that time. Due to its size and composition, the Moon is sometimes classified as a terrestrial planet along with Mercury, Venus, Earth and Mars. The Moon was first visited by the Soviet spacecraft Luna 2 in 1959. It is the only extraterrestrial body to have been visited by humans. The first landing was on July 20, 1969 (do you remember where you were?); the last was in December 1972. The Moon is also the only body from which samples have been returned to Earth. In the summer of 1994, the Moon was very extensively mapped by the little spacecraft Clementine and again in 1999 by Lunar Prospector. The gravitational forces between the Earth and the Moon cause some interesting effects. The most obvious is the tides. The Moon's gravitational attraction is stronger on the side of the Earth nearest to the Moon and weaker on the opposite side. Since the Earth, and particularly the oceans, is not perfectly rigid it is stretched out along the line toward the Moon. From our perspective on the Earth's surface we see two small bulges, one in the direction of the Moon and one directly opposite. The effect is much stronger in the ocean water than in the solid crust so the water bulges are higher. And because the Earth rotates much faster than the Moon moves in its orbit, the bulges move around the Earth about once a day giving two high tides per day. But the Earth is not completely fluid, either. The Earth's rotation carries the Earth's bulges get slightly ahead of the point directly beneath the Moon. This means that the force between the Earth and the Moon is not exactly along the line between their centers producing a torque on the Earth and an accelerating force on the Moon. This causes a net transfer of rotational energy from the Earth to the Moon, slowing down the Earth's rotation by about 1.5 milliseconds/century and raising the Moon into a higher orbit by about 3.8 centimeters per year. (The opposite effect happens to satellites with unusual orbits such as Phobos and Triton). The asymmetric nature of this gravitational interaction is also responsible for the fact that the Moon rotates synchronously, i.e. it is locked in phase with its orbit so that the same side is always facing toward the Earth. Just as the Earth's rotation is now being slowed by the Moon's influence so in the distant past the Moon's rotation was slowed by the action of the Earth, but in that case the effect was much stronger. When the Moon's rotation rate was slowed to match its orbital period (such that the bulge always faced toward the Earth) there was no longer an off-center torque on the Moon and a stable situation was achieved. The same thing has happened to most of the other satellites in the solar system. Eventually, the Earth's rotation will be slowed to match the Moon's period, too, as is the case with Pluto and Charon. Actually, the Moon appears to wobble a bit (due to its slightly non-circular orbit) so that a few degrees of the far side can be seen from time to time, but the majority of the far side (left) was completely unknown until the Soviet spacecraft Luna 3 photographed it in 1959. (Note: there is no dark side of the Moon; all parts of the Moon get sunlight half the time. Some uses of the term dark side in the past may have referred to the far side as dark in the sense of unknown (eg darkest Africa; but even that meaning is no longer valid today!) The Moon has no atmosphere. But evidence from Clementine suggested that there may be water ice in some deep craters near the Moon's south pole which are permanently shaded. This has now been confirmed by Lunar Prospector. There is apparently ice at the north pole as well. The cost of future lunar exploration just got a lot cheaper! The Moon's crust averages 68 km thick and varies from essentially 0 under Mare Crisium to 107 km north of the crater Korolev on the lunar far side. Below the crust is a mantle and probably a small core (roughly 340 km radius and 2% of the Moon's mass). Unlike the Earth's mantle, however, the Moon's is only partially molten. Curiously, the Moon's center of mass is offset from its geometric center by about 2 km in the direction toward the Earth. Also, the crust is thinner on the near side. There are two primary types of terrain on the Moon: the heavily cratered and very old highlands and the relatively smooth and younger maria. The maria (which comprise about 16% of the Moon's surface) are huge impact craters that were later flooded by molten lava. Most of the surface is covered with regolith, a mixture of fine dust and rocky debris produced by meteor impacts. For some unknown reason, the maria are concentrated on the near side. Most of the craters on the near side are named for famous figures in the history of science such as Tycho, Copernicus, and Ptolemaeus. Features on the far have more modern references such as Apollo, Gagarin and Korolev (with a distinctly Russian bias since the first images were obtained by Luna 3). In addition to the familiar features on the near side, the Moon also has the huge craters South Pole-Aitken on the far side which is 2250 km in diameter and 12 km deep making it the the largest impact basin in the solar system and Orientale on the western limb (as seen from Earth; in the center of the image at left) which is a splendid example of a multi-ring crater. A total of 382 kg of rock samples were returned to the Earth by the Apollo and Luna programs. These provide most of our detailed knowledge of the Moon. They are particularly valuable in that they can be dated. Even today, 20 years after the last Moon landing, scientists still study these precious samples. Most rocks on the surface of the Moon seem to be between 4.6 and 3 billion years old. This is a fortuitous match with the oldest terrestrial rocks which are rarely more than 3 billion years old. Thus the Moon provides evidence about the early history of the Solar System not available on the Earth. Prior to the study of the Apollo samples, there was no consensus about the origin of the Moon. There were three principal theories: co-accretion which asserted that the Moon and the Earth formed at the same time from the Solar Nebula; fission which asserted that the Moon split off of the Earth; and capture which held that the Moon formed elsewhere and was subsequently captured by the Earth. None of these work very well. But the new and detailed information from the Moon rocks led to the impact theory: that the Earth collided with a very large object (as big as Mars or more) and that the Moon formed from the ejected material. There are still details to be worked out, but the impact theory is now widely accepted. The Moon has no global magnetic field. But some of its surface rocks exhibit remanent magnetism indicating that there may have been a global magnetic field early in the Moon's history. With no atmosphere and no magnetic field, the Moon's surface is exposed directly to the solar wind. Over its 4 billion year lifetime many hydrogen ions from the solar wind have become embedded in the Moon's regolith. Thus samples of regolith returned by the Apollo missions proved valuable in studies of the solar wind. This lunar hydrogen may also be of use someday as rocket fuel.


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Shen Kua

Astronomy 201 Astronomer, Shen Kua Shen Kua was born in China in the year 1026. Shen Kua was born to Shen Chou and his wife Hsa. His family had an unbroken tradition of being civil servants. Thus his father was a local administrator of many posts from Szechwan in the west to the international port of Amoy. At Sixteen years old Shen Kua left his home to travel with his father from post to post. While traveling with his father, Shen Kua learned the responsibilities of a local administrator. These responsibilities include a broad range of technical and managerial problems in public works, finance, improvement of agriculture, and maintenance of waterways. In 1051 his father died and after a two year mourning period Shen Kua received his first appointment as a local administrator at the age of twenty two. Soon after his appointment he showed his skill in ability to plan by designing and overseeing a drainage and embankment system that reclaimed some hundred thousand acres of swampland for agriculture. A few years later he passed the national examinations and was assigned a post in Yangchow. While in Yangchow he impressed the Governor Chang Ch'u so much that he recommended that Shen be appointed to the department of Financial Administration. It was about this time that he began to study astronomy. His first works as an astronomer came when he set down clear explanations concerning the sphericity of the sun and the moon as proved by lunar phases, of eclipse limits and the retrogradation of the lunar nodes. These explanations gave the ability to visualize motions in space Which in the past was only best implicit in numerical procedures of traditional astronomy and seldomly discussed in technical writing. Because of this work Shen was given an additional appointed as director of the Astronomical Bureau. His first project as director was a major calendar reform. This reform started with a series of daily observations of the stars that lasted over five years. While these observations where being performed Shen realized the need for a major redesign of major astronomical instruments. The most significant change that Shen made was to the gnomon. The gnomon was still being used to measure the noon shadow and fix the solstices. Shen redesigned the armillary sphere that is used to make angular measurements, and the clepsydra which determines the time that observations are made. He improved the armillary sphere by improving the diameter of the naked eye sighting tube. Shen noticed that the polestar could no longer be seen in the sighting tube at night. He slowly widened the tube by using the plots of the polestar three times a night for three months to adjust the aim. His new calibration revealed that the tube was slightly three degrees off. The clepsydra also had calibration problems as well, in the past day and night were separately divided by hours. Shen realized that day and night hours were different from season to season. The time was read from float rods in an overflow-tank. Shen saw these problems and proposed a new design for these float tanks. Shen also made his mark in his discussions of solar, lunar, and eclipse phenomena. This by far was the most extraordinary of his cosmological hypothesis that accounts for variations in planetary motions that include retrogradation. Shen noted that the greatest planetary anamoloy happened near stationary points. He proposed a model that suggested that the planet moved in the shape of a willow leaf attached to one side of a periphery circle. The way the planets changed thier direction of motion in respect to the stars was explained by the travel from one point of the leaf to the other. This served the same purpose as the epicycle served in Europe Shen's writings were in part considered to be the highest achievement in traditional Chinese mathematical astronomy. After his impeachment from office at the age of fifty-one Shen moved to a small piece of land in the country. It was there that Shen completed three books and an atlas of China. One of these books was called Brush Talks From The Dream Brook. This book includes some of Shen Kua's most elaborate ideas on such things as regularities underlying the phenomenal, technical skills, deliberations of materia medica, and many miscellaneous notes.


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Orion

Orion Down fell the red skin of the lion Into the river at his feet. His mighty club no longer beat The forehead of the bull; but he Reeled as of yore beside the sea, When blinded by Oenopion He sought the blacksmith at his forge, And climbing up the narrow gorge, Fixed his blank eyes upon the sun. ~The Occultation of Orion by Mr. Longfellow~ This poem was written about the Greek myth of Orion. The story says that Orion, the son of Neptune, was a handsome giant and a mighty hunter. His father gave him the power of wading through the depths of the sea, or, as others would say, walking on its surface. Orion loved Merope, the daughter of Oenopion, king of Chios, and sought her in marriage. He cleared the island of wild beasts, and brought the spoils of the chase as presents to his beloved; but as Oenopion constantly deferred his consent, Orion attempted to gain possession of the maiden by violence. Her father, incensed at this conduct, having made Orion drunk, deprived him of his sight and cast him out on the seashore. The blinded hero followed the sound, of a Cyclops' hammer till he reached Lemnos, and came to the forge of Vulcan(Hephaestus), who, taking pity on him, gave him Kedalion, one of his men to be his guide to the abode of the sun. Placing Kedalion on his shoulders, Orion proceeded to the east, and there meeting the sun-god(Helios) was restored to sight by his beam. After this he dwelt as a hunter with Diana(Artemis), with whom he was a favorite, and it was even said she was about to marry him. Her brother was highly displeased and often chid with her, but for no purpose. One day, observing Orion wading through the sea with his head just above the water, Apollo pointed it out to his sister and maintained that she could not hit that black thing on the sea. The archer-goddess discharged a shaft with fatal aim. The waves rolled the dead body of Orion to the land, and bewailing her fatal error with many tears, Diana placed him among the stars, where he appears as a giant, with a girdle, sword, lion's skin, and club. Sirius, his dog, follows him, and the Pleiads fly before him. Orion, the brightest constellation in the sky, is easy to find if you look for the three bright stars that make up Orion's belt. Once you have found this distinctive pattern, two other very bright stars will help you define the rest of the constellation. The first star, Betelgeuse, is located at Orion's right shoulder. The second, Rigel, is at his lower left. Orion is the great hunter, aiming his arrow and holding his club over his head. His sword hangs from his belt. In the area of this sword are found a number of very exciting star formation regions, including the Great Nebula of Orion. The nebula is visible with the unaided eye, as a smudge about halfway down his sword. The Great Nebula of Orion(star M42) is one of the most photographed objects in the sky. This area is a collection of gas and dust where stars are being born. The central bright star that is illuminating the gaseous cloud is actually four stars known as the Trapezium. The nebula itself is one of the nearest star formations at only about 1,500 light years away. It has formed stars recently, only 300,000 years ago. In Orion many of the stars have different colors, colors tell us about a star's temperature, composition, age, size, and distance from us. Red stars are generally older, cooler stars that have used up much of their hydrogen fuel. Blue stars are generally younger and hotter. Most of these stars are blue, with the exception of the very red star, Betelgeuse. Betelgeuse is a red supergiant, Rigel is a blue supergiant. The red streak in the sword area is the Orion Nebula. Orion is located in the celestial equator and Orion's outstretched upper arm is located in the Milky Way. Orion is followed by two hunting dogs at his right. One of these, Canis Major, contains the brightest star in the sky. This star, Sirius, is located just where the dog's neck meets his body. Sirius should help you find Orion, and Orion is also shooting at Taurus the Bull.

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Origin Of Solar System

The Origin of the Solar System One of the most intriguing questions in astronomy today is the how our solar system formed. Not only does the answer add insight to other similarly forming systems, but also helps to satisfy our curiosity about the origin of our species. Although it is highly unlikely that astronomers will ever know with absolute scientific certainty how our system originated, they can construct similar theoretical models with the hopes gaining a better understanding. A basic understand of the current physical aspects of our solar system are helpful when trying to analyzing its origin. Our solar system is made of the Sun, nine major planets, at least sixty planetary satellite, thousands of asteroids and comets that all span an immense distance. Each planet has its own individual characteristics and seven of which have one or more satellites. There are thousands of asteroids, mainly congested in the area between Mars and Jupiter, as well as countless comets that all travel in a spherical orbit around our Sun. The Sun contains approximately 99 percent of the mass in the solar system, but only 2 percent of the system’s angular momentum. It lies in the center of our system while all planets, asteroids and alike rotate in elliptical orbits around it in the same plane. The smaller inner planets have solid surfaces, lack ring systems and have far fewer satellites then the outer planets. Atmospheres of most of the inner planets consist of large quantities of oxidized compounds such as carbon dioxide. While on the other hand, the outer planets are far more massive then the inner terrestrial planets, and have gigantic atmospheres composed mainly of hydrogen and helium. Asteroids and comets make up the smallest portion of the solar systems entities and are composed of the remnants left behind while planets were forming. For over 300 years, there has been a very long history of conjecture on the origin of the solar system. These many theories stem from two general categories. The first category called monistic, involves the evolution of the Sun and planets as an isolated system. The second group of theories called dualistic, suggested that the solar system formed as a result of the interaction between two individual stars. The dualistic formation theory has been almost entirely dropped and monistic formation has become the general consensus on the basic formation of our solar system. Most modern theories of the origin of the solar system hypothesize that all bodies in the solar system, including the sun accreted from the formation and evolution of a single primordial solar nebula. It is believed that our solar system began to form around 4.56 billion years ago from a dense interstellar cloud of gas. Because of the conservation of angular momentum, the cloud of gas formed a rotating flattened disk approximately the size of the planetary system. It was this flattened disk that is referred to as the primitive solar nebula and from which our current solar system evolved. Ordinarily, the internal pressures of the cloud are sufficient to prevent if form collapsing. However, from time to time local increases in pressure of the interstellar medium cause the additional compression of interstellar clouds. These compressions caused the clouds to reach their threshold of gravitational collapse. Once the gravitational attraction of matter is greater then any tendency to expand due to internal pressures the cloud begins to collapse inward. Theoretical models suggest that the presolar nebula continued to collapse until the center of the cloud became so dense that heat started to form. This heat increased the thermal pressure of the cloud until the collapse was eventually halted. The existence of our system of planets is entirely due to the angular momentum of the initial cloud. If there were no angular momentum, then the interstellar cloud would have collapsed to from a single star. While at the same time, if the collapse had occurred under a system with too much angular momentum then a binary star would have resulted from our system. Our system formed under intermediate conditions allowing the planets to evolve. The fact that the Sun contains 99 percent of the solar system’s mass but only 2 percent of its angular momentum raises questions about the distribution of masses during the early formation of the solar system. It is suggested that certain processes transported nebula mass inward to form the Sun, and angular momentum outward to the preplanetary region. Thus decreasing the total angular momentum of the Sun. Three separate hypothesizes have been suggested to explain the processes for such a transport. The main theories suggest that gravitational torques, viscous stress, and magnetic fields may have acted individually or in some combination to produce our present system. The first theory including gravitational torques arises from the gravitational forces between segments of asymmetric mass. One example of this case would be between inner and outer regions of the trailing spiral arms of the nebula. Assuming there is a source of asymmetry, then these torques can result in significant outward transportation of angular momentum. Viscous stresses are another possible source of the shift in angular momentum of the solar system during its evolution. Viscous stresses are caused by the friction between adjacent fluid parcels trying to move past each other with different speeds. These stresses result in the outward transport of angular momentum and are one more possible explanation to the outward spread of momentum. The third theory postulates that magnetic fields are the source of this momentum transfer. Magnetic fields may have been produced during the collapse of the initial cloud or even electrically generated between the proto-Sun and the solar nebula. This would eventually end in the same result of an outward spread of angular momentum. Therefore the evolution of the solar nebula involved both the transportation of mass into the central proto-Sun region and the increased angular momentum in the planetary regions. This meant that most of the primitive cloud’s mass fell in to the proto-Sun’s region while the remainder formed the planets. It is not only important to study the evolution of the solar nebula, but also the formation of the planets. There is a general consensus that once the solar nebula settled to rest that solid dust particles began to move toward the central plane of the nebula. It was at this stage that the planets began to form. There are two current theories that resulted in the development of the planets. The first theory suggests that the planets formed in a very basic process where dust particles accumulated into planetesimals which in turn grew to the present planets. The second theory proposes that planetesimals resulted from a gravitational instability in the gaseous portion of the solar nebula. The first theory states process of planet formation began with the settling of dust in into the central plane of the nebular disk. Soon after, the first dust particles began to coagulate into small solid bodies. These bodies then accumulated through a collective gravitational instability in of the dust disk. The thin dust disk became more massive through continual sedimentation and resulted in its breakup into a large number of planetesimals. Through a process of random collisions these planetesimal continued to grow and accumulate mass. There are two possible extremes that ended this process of accumulation. The first involved runaway accreting where one object grows extremely large through the collection of all smaller planetesimals within its area. The alternative extreme would involve the uniform growth of a number of masses resulting in a many equal mass planetesimals. It is currently believed that the formation of the planets resulted from a combination of these two processes. The equal mass accumulation is presumed to have dominated during the early stages of planet formation while the run away accumulation is suggested to have taken over during the latter stages. However, there is one substantial problem with this explanation of the planet's formation. The accumulation theory fails to take into account the rapid formation of the giant planets. By the slow process of coagulation, it would take much longer then the lifetime of the solar system to form the giant planets of Jupiter and Saturn. This incorrectness in the first theory led scientists to contrive the second theory. The second theory of planetary evolution involves a gravitational instability of the gaseous portion of the solar nebula. It is suggested that if the solar system were massive enough then the instability would lead to the fragmentation of the gaseous nebula and the formation of giant gaseous protoplanets. This theory allows plenty of time for the formation of the very large planets Jupiter and Saturn. The one flaw of this theory is its contingency on a very massive planetary nebula, one much larger than ours. Because of this problem many cosmogonists have begun to doubt that the gaseous disk instability led to planet formation in our solar system. Although many of the details on the theories of our solar system will most likely change in the near future, the fundamental concept of solar system formation appear to remain the same. The Sun and planets began forming approximately 4.56 billion years ago out of a solar nebula produced by the collapse of a rotating interstellar cloud of gas and dust. Following soon after, the terrestrial and Jovian planets eventually formed from the collision and accumulation of smaller planetesimals. While there is significant evidence supporting the formation of the Sun and planets in this way, it is not likely that scientist will know with complete certainty about the solar system’s origin for some time. It is highly likely that the details in the theory of the solar system will change. With continued improvements in technology and significant advances in astronomical fields of observation, further understanding of our solar system will undoubtedly come. In recent years, the idea that the Solar System formed from the evolution of a primodial solar nebula, has received significant conformation. The use of satellites such as the Infrared Astronomical Satellite (IRAS) have detected disks of solid particles around several nearby stars, including Formalhaut, Beta Pictoris and Vega. The uses of satellites have provided scientists with most of the information they currently have on the system’s origin. Another source of information lies in our neighboring planets. Investigations of the other planets in the solar system by means of interplanetary spacecraft have provided a wealth of data pertaining to the origin and history of the solar system. Through the observation of solar-type stars in the Galaxy, we can learn critical information about the properties of the interstellar cloud that collapsed to form our own solar nebula. It is likely that future explorations and observations will help to solidify our understanding of the solar system.

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Native American Astronomy

For many years astronomers and people alike have constantly heard about the observations and records of the Chinese and Europeans. No other culture can provide as much information as that gathered by the Chinese and Europeans, but there are many other cultures that observed and recorded the night sky, one of those being the Native Americans. During the last fifteen to twenty years archaeoastronomers have uncovered much concerning the beliefs and records of Native Americans. Unfortunately, the methods of keeping records of astronomical events were not as straight forward as the Chinese and Europeans. The Native Americans had to use what they could to record what they observed. Their records were found on rock and cave drawings, stick notching, beadwork, pictures on animal skins and story telling. One of the few dateable events among the various records of Native Americans was the 1833 appearance of the Leonid meteor shower. The most obvious accounts of the Leonid storm appear among the various bands of the Sioux of the North American plains. The Sioux kept records called “winter counts,” which were a chronological pictographic account of each year painted on animal skin. In 1984 Von Del Chamberlain listed the astronomical references for 50 Sioux, forty five out of fifty referred to an intense meteor shower during 1833/1834. He also listed nineteen winter counts kept by other plains Indian tribes, fourteen of which referred to the Leonid storm. The Leonids also appear among the Maricopa, who used calendar sticks with notches to represent the passage of a year, with the owner of the stick remembering the events. The owner of one stick claimed records had been kept that way “since the stars fell.” The first notch on the stick represented 1833. A member of the Papago, named Kutox, was born around 1847 or 1848. He claimed that 14 years prior to his birth “the stars rained all over the sky.” A less obvious Leonid reference was found in a journal kept by Alexander M. Stephen, which detailed his visit with the Hopi Indians and mentions a talk he had With Old Djasjini on December 11, 1892. That Hopi Indian said, “How old am I? Fifty, maybe a hundred years, I cannot tell. When I was a young boy eight or ten years there was a great comet in the sky and at night all the above was full of shooting stars. (Stephen 37). During the lifetime of Old Djasini there was never a great comet and a sky full of meteors in the same year, but he might be referring to the comet in 1843 and the Leonid storm in 1833. The Pawnee have a story about a person named Pahokatawa, who was killed by an enemy and eaten by animals, and then brought back to life by the Gods. The legend goes that he fell to earth as a meteor and told the people that when meteors were seen falling in great numbers it was not a sign that the world would end. When the pawnee tribe witnessed the time the stars fell upon the earth, which was in 1833, there was a panic, but the leader said, “remember the words of Pahokatawa” and the people were no longer afraid. This shows how powerful a role astronomy played in the Native American culture. Although the Pawnee learned not to be afraid there were Native Americans who feared meteors. The Blackfeet of Montana believed a meteor was a sign that sickness would come to the tribe in the winter the Kawaiisu thought a meteor started high and fell to the horizon was an omen of death. The Cahuilla thought a meteor was the spirit of their first shaman, takwich, who was disliked his people. Takwich wandered the sky at night looking for people far from their tribe. If he found a lost person he steal their spirit and the person home and eat them. The Shawnee believed meteors were beings fleeing from the wrath of some adversary, or from some anticipated danger.(Howard 178) Many Native Americans saw the stars as heavenly and mystical. The Wintu explained meteors as the spirits of shamans traveling to the after life. The Chumash referred to meteors as a shooting star. They believed a meteor was a person’s soul on their way to the afterlife. The Eastern Pomo believed meteors were fire dropping from the sky. The most widely accepted belief was that meteors were the feces of stars. (Hudson 40) The Ojibwa of the upper Great Lakes had a story about Genondahwayanung, which meant, “Long tailed heavenly climbing star.” An Ojibwa says that Genondahwayanung was a star with a long wide tail which would return and destroy the world someday. The shaman said it came down one thousand years ago. He said it was just like sun, radiation, burning heat in its tail. The comet was said to have scorched earth except for Native Americans, who were warned by a Holy Spirit, Chimantou. The animals were killed off it was so hot stones were said to have melted. It is said the comet came down and spread for miles. Another form of record keeping were rock petroglyphs, or pictures carved into rock. The western part of the United States is filled with these pictures, but any dating is virtually impossible. It is very difficult to determine whether or not the object drawn is a meteor or a comet. The most common petroglyphs are a circle with a wiggly line coming from it. Various archaeologists have interpreted these as meteors, comets and snakes Records were also kept in the form of pottery. A Hopi jar that was found had a scene that had mountains, stars and three objects falling towards the ground. This scene implies a meteor shower or a meteor that broke up as it fell. It may be possible that this jar depicts the Leonid storm of 1833. (Hudson 41) Native Americans also attained their records by building structures that would observe the sun. the Bighorn Medicine Wheel in Wyoming dates to AD 1400 to 1700. Lines drawn between major markings on the wheel point to the location of solstice sunrises and sunsets and also toward the rising point of the three brightest stars that rise before the sun in the summer. About fifty medicine wheels have been discovered, several are thousands of years. Many of them have the same alignment as the Bighorn Medicine Wheel. In Chaco Canyon, New Mexico two spirals carved into the rock by the prehistoric Anasazi can be used as a calendar. A dagger of light penetrates the shadow of adjacent rocks. The dagger moves with the sun to different locations on the spiral.the full pattern also reflects the 18.6 year cycle of the moon as well as the yearly cycle of the sun. The ancient Native Americans were not sophisticated astronomers in the sense of coherent theory behind the movements of heavenly objects, their level of understanding of the time cycles of the sun, moon and planets was great. The methods for recording and keeping track of the seasonal movements was clever and displays a cultural richness that varies from tribe to tribe.

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Galileo Galilei

Galileo Galilei's father, Vincenzo Galilei (c.1520 - 1591), who described himself as a nobleman of Florence, was a professional musician. He carried out experiments on strings to support his musical theories. Galileo studied medicine at the university of Pisa, but his real interests were always in mathematics and natural philosophy. He is chiefly remembered for his work on free fall, his use of the telescope and his employment of experimentation. After a spell teaching mathematics, first privately in Florence and then at the university of Pisa, in 1592 Galileo was appointed professor of mathematics at the university of Padua (the university of the Republic of Venice). There his duties were mainly to teach Euclid's geometry and standard (geocentric) astronomy to medical students, who would need to know some astronomy in order to make use of astrology in their medical practice. However, Galileo apparently discussed more unconventional forms of astronomy and natural philosophy in a public lecture he gave in connection with the appearance of a New Star (now known as 'Kepler's supernova') in 1604. In a personal letter written to Kepler (1571 - 1630) in 1598, Galileo had stated that he was a Copernican (believer in the theories of Copernicus). No public sign of this belief was to appear until many years later. In the summer of 1609, Galileo heard about a spyglass that a Dutchman had shown in Venice. From these reports, and using his own technical skills as a mathematician and as a workman, Galileo made a series of telescopes whose optical performance was much better than that of the Dutch instrument. The astronomical discoveries he made with his telescopes were described in a short book called Message from the stars (Sidereus Nuncius) published in Venice in May 1610. It caused a sensation. Galileo claimed to have seen mountains on the Moon, to have proved the Milky Way was made up of tiny stars, and to have seen four small bodies orbiting Jupiter. These last, with an eye on getting a job in Florence, he promptly named 'the Medicean stars'. It worked. Soon afterwards, Galileo became 'Mathematician and [Natural] Philosopher' to the Grand Duke of Tuscany. In Florence he continued his work on motion and on mechanics, and began to get involved in disputes about Copernicanism. In 1613 he discovered that, when seen in the telescope, the planet Venus showed phases like those of the Moon, and therefore must orbit the Sun not the Earth. This did not enable one to decide between the Copernican system, in which everything goes round the Sun, and the Tychonic (Tycho Brahe) one in which everything but the Earth (and Moon) goes round the Sun which in turn goes round the Earth. Most astronomers of the time in fact favoured the Tychonic system. However, Galileo showed a marked tendency to use all his discoveries as evidence for Copernicanism, and to do so with great verbal as well as mathematical skill. He seems to have made a lot of enemies by making his opponents look fools. Moreover, not all of them actually were fools. There eventually followed some expression of interest by the Inquisition. Prima facie, Copernicanism was in contradiction with Scripture, and in 1616 Galileo was given some kind of secret, but official, warning that he was not to defend Copernicanism. Just what was said on this occasion was to become a subject for dispute when Galileo was accused of departing from this undertaking in his Dialogue concerning the two greatest world systems, published in Florence in 1632. Galileo, who was not in the best of health, was summoned to Rome, found to be vehemently suspected of heresy, and eventually condemned to house arrest, for life, at his villa at Arcetri (above Florence). He was also forbidden to publish. By the standards of the time he had got off rather lightly. Galileo's sight was failing, but he had devoted pupils and amanuenses, and he found it possible to write up his studies on motion and the strength of materials. The book, Discourses on two new sciences, was smuggled out of Italy and published in Leiden (in the Netherlands) in 1638. Galileo wrote most of his later works in the vernacular, probably to distance himself from the conventional learning of university teachers. However, his books were translated into Latin for the international market, and they proved to be immensely influential.

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Copernicus

Nicolas Copernicus Nicolas Copernicus 1473-1543 Physics February 8, 2000 Nicolas Copernicus Nicolas Copernicus 1473-1543 Copernicus was born in Poland in 1473, he started his education at Cracow University. There he studied mathematics and optics. From here he went to Italy, where he was appointed as a canon in the cathedral of Frauenburg, where he spent a comfortable academic life studding. Copernicus had some small hobbies while at the cathedral, he painted, and frequently translated Greek poetry into Latin. One other hobby that just wasn't small enough to be called a hobby to most of us was astronomy. He made investigations quietly and alone, without any help. He observed from a turret on a protective wall around a cathedral, he also looked with his naked eye rather than with a telescope. He was one of the founders of modern astronomy. Copernicus died in 1543 of a cerebral hemorrhage. In 1530 right before Copernicus died he managed to published his work, De Revolutionibus. Which said that the earth rotated on its axis once daily and traveled around the sun once yearly. This might no sound very controversial but at this time the church and its followers believed in the Ptolemiac theory, which stated that the universe was a closed space bounded by a spherical envelope beyond which there was nothing. (Landry 1999) Copernicus’s works went against the church, and most scientific beliefs. This may be one reason why Copernicus didn’t publish his work until his deathbed. Another reason may be that Copernicus was a huge perfectionist, and continuously redid his works over and over to get them right. (Field 1995) So you can see why Copernicus wasn’t in any big rush to have the world know about his theory. On one hand he would cause a Nicolas Copernicus tramoundous stir in the church, and all the scientific community. He would’ve most likely have been fired from the comfortable church position he had for many years, and could‘ve given him a bad name. If it hadn’t been for George Rheticus, a 25-year-old German mathematics professor Copernicus’s might have never publiched his work. (Field 1995) Rheticus stayed with Copernicus for two years, and convinced him to release his work. “His work the Copernicus's heliostatic cosmology involved giving several distinct motions to the Earth. It was consequently considered implausible by the vast majority of his contemporaries, and by most astronomers and natural philosophers of succeeding generations before the middle of the seventeenth century. Its only defenders included Johannes Kepler (1571 -1630) and Galileo Galilei (1564- 1642). Strong theoretical underpinning for the Copernican theory was provided by Newton's theory of universal gravitation (1687).” (Field 1995) So Copernicus’s whole argument stated that the planets and the Earth were in orbit around the sun, and the moon was in orbit around the Earth. This is called the The Heliocentric System: Nicolas Copernicus In conclusion Copernicus said that the Sun was the center of the universe, and went against all known knowledge, religion, and teachings. He took all his observations with the naked eye and with no help. Many disregarded his book and his theory, which went against everything that the church believed in. However if it wasn’t for Copernicus, modern astronomy would have never made advances as far as it has to today. Copernicus’s hard work and strength is why he is one of the most important founders of modern astronomy. BibliographyField, J. V. (1995 August). Home page. [Online]. [2000, Feb. 8]. Astronomy 161 “The Solar System” . [Online]. University of Florida. [2000, Feb. 8]. Landry, Peter (1999 June). Home page. [Online]. Dartmouth, Nova Scotia. CANADA. [2000, Feb. 8].

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Black Holes

stence. The Search for Black Holes: Both As A Concept And An Understanding For ages people have been determined to explicate on everything. Our search for explanation rests only when there is a lack of questions. Our skies hold infinite quandaries, so the quest for answers will, as a result, also be infinite. Since its inception, Astronomy as a science speculated heavily upon discovery, and only came to concrete conclusions later with closer inspection. Aspects of the skies which at one time seemed like reasonable explanations are now laughed at as egotistical ventures. Time has shown that as better instrumentation was developed, more accurate understanding was attained. Now it seems, as we advance on scientific frontiers, the new quest of the heavens is to find and explain the phenomenom known as a black hole. The goal of this paper is to explain how the concept of a black hole came about, and give some insight on how black holes are formed and might be tracked down in our more technologically advanced future. Gaining an understanding of a black hole allows for a greater understanding of the concept of spacetime and maybe give us a grasp of both science fiction and science fact. Hopefully, all the clarification will come by the close of this essay. A black hole is probably one of the most misunderstood ideas among people outside of the astronomical and physical communities. Before an understanding of how it is formed can take place, a bit of an introduction to stars is necessary. This will shed light (no pun intended) on the black hole philosophy. A star is an enormous fire ball, fueled by a nuclear reaction at its core which produces massive amounts of heat and pressure. It is formed when two or more enormous gaseous clouds come together which forms the core, and as an aftereffect the conversion, due to that impact, of huge amounts of energy from the two clouds. The clouds come together with a great enough force, that a nuclear reaction ensues. This type of energy is created by fusion wherein the atoms are forced together to form a new one. In turn, heat in excess of millions of degrees farenheit are produced. This activity goes on for eons until the point at which the nuclear fuel is exhausted. Here is where things get interesting. For the entire life of the star, the nuclear reaction at its core produced an enormous outward force. Interestingly enough, an exactly equal force, namely gravity, was pushing inward toward the center. The equilibrium of the two forces allowed the star to maintain its shape and not break away nor collapse. Eventually, the fuel for the star runs out, and it this point, the outward force is overpowered by the gravitational force, and the object caves in on itself. This is a gigantic implosion. Depending on the original and final mass of the star, several things might occur. A usual result of such an implosion is a star known as a white dwarf. This star has been pressed together to form a much more massive object. It is said that a teaspoon of matter off a white dwarf would weigh 2-4 tons. Upon the first discovery of a white dwarf, a debate arose as to how far a star can collapse. And in the 1920’s two leading astrophysicists, Subrahmanyan Chandrasekgar and Sir Arthur Eddington came up with different conclusions. Chandrasekhar looked at the relations of mass to radius of the star, and concluded an upper limit beyond which collapse would result in something called a neutron star. This limit of 1.4 solar masses was an accurate measurement and in 1983, the Nobel committee recognized his work and awarded him their prize in Physics. The white dwarf is massive, but not as massive as the next order of imploded star known as a neutron star. Often as the nuclear fuel is burned out, the star will begin to shed its matter in an explosion called a supernovae. When this occurs the star loses an enormous amount of mass, but that which is left behind, if greater than 1.4 solar masses, is a densely packed ball of neutrons. This star is so much more massive that a teaspoon of it’s matter would weigh somewhere in the area of 5 million tons in earth’s gravity. The magnitude of such a dense body is unimaginable. But even a neutron star isn’t the extreme when it comes to a star’s collapse. That brings us to the focus of this paper. It is felt, that when a star is massive enough, any where in the area of or larger than 3-3.5 solar masses, the collapse would cause something of a much greater mass. In fact, the mass of this new object is speculated to be infinite. Such an entity is what we call a black hole. After a black hole is created, the gravitational force continues to pull in space debris and all other types of matter in. This continuous addition makes the hole stronger and more powerful and obviously more massive. The simplest three dimensional geometry for a black hole is a sphere. This type of black hole is called a Schwarzschild black hole. Kurt Schwarzschild was a German astrophysicist who figured out the critical radius for a given mass which would become a black hole. This calculation showed that at a specific point matter would collapse to an infinitely dense state. This is known as singularity. Here too, the pull of gravity is infinitely strong, and space and time can no longer be thought of in conventional ways. At singularity, the laws defined by Newton and Einstein no longer hold true, and a myterious world of quantum gravity exists. In the Schwarzschild black hole, the event horizon, or skin of the black hole, is the boundary beyond which nothing could escape the gravitational pull. Most black holes would tend to be in a consistent spinning motion, because of the original spin of the star. This motion absorbs various matter and spins it within the ring that is formed around the black hole. This ring is the singularity. The matter keeps within the Event Horizon until it has spun into the center where it is concentrated within the core adding to the mass. Such spinning black holes are known as Kerr Black Holes. Roy P. Kerr, an Australian mathematician happened upon the solution to the Einstein equations for black holes with angular momentums. This black hole is very similar to the previous one. There are, however, some differences which make it more viable for real, existing ones. The singularity in the this hole is more time-like, while the other is more space-like. With this subtle difference, objects would be able to enter the black whole from regions away from the equator of the event horizon and not be destroyed. The reason it is called a black hole is because any light inside of the singularity would be pulled back by the infinite gravity so that none of it could escape. As a result anything passing beyond the event horizon would dissappear from sight forever, thus making the black hole impossible for humans to see without using technologicalyl advanced instruments for measuring such things like radiation. The second part of the name referring to the hole is due to the fact that the actual hole, is where everything is absorbed and where the center core presides. This core is the main part of the black hole where the mass is concentrated and appears purely black on all readings even through the use of radiation detection devices. The first scientists to really take an in depth look at black holes and the collapsing of stars, were a professor, Robert Oppenheimer and his student Hartland Snyder, in the early nineteen hundreds. They concluded on the basis of Einstein's theory of relativity that if the speed of light was the utmost speed over any massive object, then nothing could escape a black hole once in it's clutches. It should be noted, all of this information is speculation. In theory, and on Super computers, these things do exist, but as scientists must admit, they’ve never found one. So the question arises, how can we see black holes? Well, there are several approaches to this question. Obviously, as realized from a previous paragraph, by seeing, it isn’t necessarily meant to be a visual representation. So we’re left with two approaches. The first deals with X-ray detection. In this precision measuring system, scientists would look for areas that would create enormous shifts in energy levels. Such shifts would result from gases that are sucked into the black hole. The enormous jolt in gravitation would heat the gases by millions of degrees. Such a rise could be evidence of a black hole. The other means of detection lies in another theory altogether. The concept of gravitational waves could point to black holes, and researchers are developing ways to read them. Gravitational Waves are predicted by Einstein’s General Theory of Relativity. They are perturbations in the curvature of spacetime. Sir Arthur Eddington was a strong supporter of Einstein, but was skeptical of gravity waves and is reported to have said, Graviatational waves propagate at the speed of thought. But what they are is important to a theory. Gravitational waves are enormous ripples eminating from the core of the black hole and other large masses and are said to travel at the speed of light, but not through spacetime, but rather as the backbone of spacetime itself. These ripples pass straight through matter, and their strength weakens as it gets farther from the source. The ripples would be similar to a stone dropped in water, with larger ones toward the center and fainter ones along the outer circumference. The only problem is that these ripples are so minute that detecting them would require instrumentation way beyond our present capabilities. Because they’re unaffected by matter, they carry a pure signal, not like X-rays which are diffused and distorted. In simulations the black hole creates a unique frequency known as it natural mode of vibrations. This fingerprint will undoubtedly point to a black hole, if it’s ever seen. Just recently a major discovery was found with the help of The Hubble Space Telescope. This telescope has just recently found what many astronomers believe to be a black hole, after being focused on a star orbiting an empty space. Several picture were sent back to Earth from the telescope showing many computer enhanced pictures of various radiation fluctuations and other diverse types of readings that could be read from the area in which the black hole is suspected to be in. Because a black hole floats wherever the star collapsed, the truth is, it can vastly effect the surrounding area, which might have other stars in it. It could also absorb a star and wipe it out of existance. When a black hole absorbs a star, the star is first pulled into the Ergosphere, this is the area between the event horizon and singularity, which sweeps all the matter into the event horizon, named for it's flat horizontal appearance and critical properties where all transitions take place. The black hole doesn’t just pull the star in like a vaccuum, rather it creates what is known as an accretion disk which is a vortex like phenomenom where the star’s material appears to go down the drain of the black hole. When the star is passed on into the event horizon the light that the star ordinarily gives off builds inside the ergosphere of the black hole but doesn’t escape. At this exact point in time, high amounts of radiation are given off, and with the proper equipment, this radiation can be detected and seen as an image of emptiness or as preferred, a black hole. Through this technique astronomers now believe that they have found a black hole known as Cygnus X1. This supposed black hole has a huge star orbiting around it, therefore we assume there must be a black hole that it is in orbit with. Science Fiction has used the black hole to come up with several movies and fantastical events related to the massive beast. Tales of time travel and of parallel universes lie beyond the hole. Passing the event horizon could send you on that fantastical trip. Some think there would be enough gravitational force to possible warp you to an end of the universe or possibly to a completely different one. The theories about what could lie beyond a black hole are endless. The real quest is to first find one. So the question remains, do they exist? Black holes exist, unfortunately for the scientific community, their life is restricted to formulas and super computers. But, and there is a but, the scientific community is relentless in their quest to build a better means of tracking. Already the advances of hyper-sensitive equipment is showing some good signs, and the accuracy will only get better.

Words: 2172

Astrology

Have you ever wondered what the signs of the Zodiac means? When we turn on the TV it seems we always see an advertisement on horoscope predictions. People call in and get the predictions they have been looking for. When the newspaper first arrives, some people go to the horoscope section first. They base the entire day or entire week on the report they get. It seems that this phenomenon is something all new, or is it? Astrology has been around since ancient times, even dating back to biblical days. Astrology has a long line of history and a bright future. We will attempt to cover that topic as well as the signs and elements of the Zodiac. The signs of the Zodiac include: Aries, Taurus, Gemini, Cancer, Leo, Virgo, Libra, Scorpio, Sagittarius, Capricorn, Aquarius and Pisces. Astrologers also claim the planets play a role in many key factors. How do these things affect us? We will also look at astrology as a science; a way to predict and control your life and your destiny. Although many people refer to astrology as just being superstitious others say the predictions are not worth the paper they are written on. Many men and women have studied astronomy but we will look at Mother Shipton. What caused this woman to focus her life on the study of astrology? Why did she believe astrology could predict one’s character or life? Was she just passing on false information or is the universe interrelated and everything is based on these Zodiac signs? Astrology is a phenomenon that dates back to biblical days. There is an ancient legend, that Adam received the doctrines and mysteries of astrology direct from his Maker and thus by foreknowing that the earth was to be destroyed first by fire and afterwards by water. (Thompson 17) Astrology has played an important role in our civilization. Starting with Adam and even being present in today’s society. Different civilizations seemed to be practicing astrology independetely. People noticed the Sun in particular had a change on how crops grew. Many people viewed astronomy and astrology as a similar science until the 1500s. People knew by looking at the sun or what the size of the moon was when to plant crops or even when a baby was going to be born. These early astrologers were searching for their place in life. A place where they fit into the universe. They believed that every component of the universe was linked together and everyone had their own place. Every aspect of one’s life was based on the planets and the stars. Even behavior was blamed on the position of the sun! Astrology is widely practiced today. Even today most farmers have a Farmer’s Almanac. This book tells you when to plant your crops, and many people have success. Some won’t even think about planting crops without this information. This is a form of astrology, although many people do not realize it. A popular form of astrology is the Physic Friends Network. This is a 900 number you can call in to see what your sign is and how this affects you. The astrologers on the Physic Friends Network always seem to know what has happened in the past and what will occur in the future. Everyone who says they are astrologers obviously are not and it’s up to us to use our own judgment to decide. When you hear people talk about signs of the Zodiac you often Wonder what does that mean? Ancient astronomers noted that the sun makes a yearly journey across the celestial sphere, part of which is represented in the picture by the blue band. The ancient astronomers associated dates with the constellations in this narrow belt (which is known as the zodiac), assigning to each constellation of stars the dates when the sun was in the same region of the celestial sphere as the constellation. (Encarta 1999) Each Zodiac sign belongs to four different elements: Fire, Air, Earth and Water. Fire is a positive element; this element focuses on changing energy from one form to another. Air is also a positive element that is associated with the spiritual part of life. Earth on the other hand is a negative element that is solid and approves of people on earth. The last element is water this is to a negative element that tends to be mysterious. The following is a chart that will list each Zodiac sign: When you are born within a certain month you automatically are assigned a zodiac sign. For example, I was born in July: therefore, I am a Cancer. Cancer people tend to “ be great nuturers of humankind. Like rivers they flow into any vacant heart, providing a healthy heart.” (Elliott 76) Astrologers say they can predict your life through this sign but often you can be very similar to other zodiac signs. Astrologers say that the best way to explain zodiac signs is to “imagine that your divine spirit is imprisoned in an earthly form, much like animals in a cage.” They can predict what moods you will be in, what type of person you will marry or even the sports you like to play! These kinds of predictions may or may not come true. Not all astrologers can understand or interpret your true readings. Even if you do not believe in astrology, you can still have a good time. When you pay a minimal charge to find out what the future holds for you, you always want to hear good news. Although sometimes there will be bad news as well. The next idea we will look into is that the planets play a role in astrology. The sun and the moon play an important role acting as a mom and a dad. The planets tend to effect our lives in a way many of us are unaware. Each planet has its own reason for existing. Mercury for instance “is the planet closest to the sun, it plays as the communications network for the entire solar system.” (Elliott 38) Each planet has a zodiac sign which aids in the predictions. When people are born and a planet is rising this is considered to be their planet. Astrologers have mapped out what the Saturn people or the Mars people are actually like! Through many years of study and practice astrologers are able to predict futures and destines. The planets play an important role in our universe. Research has been done to prove that the weather and earthquakes can be determined through a close look at the planets. The developments are still in the first stages. The future of astrology could be significant in the predictions of dangerous hurricanes and earthquakes. These facts may aid in saving lives. Astrologers served in the king’s court in early times to predict many things. When a battle was going to take pace or even the fate of their kingdoms. Many astrologers held influential and well paid positions. The one astrologer that some people say existed in Henry VII’s time was a woman named Mother Shipton. Her fame was spread and everyone came to visit her. Her prophecies came true and she was feared throughout the land. She phropisied death and she was always correct. Mother Shipton said “All I can say is, that I fear they will prove true than most men imagine.” (Thompson 204) Everyone feared a prediction on themselves. Mother Shipton was born in “1488 in Norfolk, England, and died in 1561. She exhibited prophetic and physic abilities from an early age”.(www.newage.com.au/library/shipton.html) This was a very intriguing woman, who could predict ones future. It is rumored that she was related to the devil himself. She predicted events in her own day as well as the future. Astrology has a rich history and even dates back to the BC days. It has been said that Adam had practiced astrology and received this message from his Maker. Astrologers say they can predict: weather, babies being born, destiny, romance or when to plant crops. The predictions come from the studies of the Zodiac signs and the planets. Everyone’s life is based on your Zodiac sign. What month you are born in determines everything about you. Your bad behavior can now be blamed on the position of the sun! It seems that a lot of groups these days are trying to make a profit on their predictions. The Physic Friends Network try to capitalize on their knowledge. You can call in and get your physic reading. The sun and the moon play a huge part in determining your signs and this is how they determine their predictions. There are four grouping that each zodiac sign can be placed into: Fire, Air, Earth and Water. Fire and Air are both positive which leaves Earth and Water negative. These grouping have a specific meaning and association. Your zodiac sign will follow you throughout life and direct you in the right path. You may not always be the textbook Cancer, you could pick up a trait or two of the Scorpio grouping. Astrologers say that planets play a role in the aiding of predictions. Each planet has its own meaning and even a zodiac sign. Research has been done proving that weather and earthquakes can be predicted by observing the planets. Unfortunately, the research is still in the development stages. This research could be beneficial to all of us and could save lives. One famous astrologer was Mother Shipton from Norfolk, England. She was a woman who could predict life, death and even sickness. It was rumored that she was related to the devil himself! She was famous throughout the Norfolk area. Often respected and feared. Many of the early pioneers lead the way for astrologers in toady’s world. In closing, the paper you have just read in no way encourages or discourages astrology. Many people believe and respect this way of life. Astrology is a very complex and misunderstood subject. It requires talent and skill. The future of astrology looks bright, and will go on for a very long time. Have you ever wondered what the signs of the Zodiac means? When we turn on the TV it seems we always see an advertisement on horoscope predictions. People call in and get the predictions they have been looking for. When the newspaper first arrives, some people go to the horoscope section first. They base the entire day or entire week on the report they get. It seems that this phenomenon is something all new, or is it? Astrology has been around since ancient times, even dating back to biblical days. Astrology has a long line of history and a bright future. We will attempt to cover that topic as well as the signs and elements of the Zodiac. The signs of the Zodiac include: Aries, Taurus, Gemini, Cancer, Leo, Virgo, Libra, Scorpio, Sagittarius, Capricorn, Aquarius and Pisces. Astrologers also claim the planets play a role in many key factors. How do these things affect us? We will also look at astrology as a science; a way to predict and control your life and your destiny. Although many people refer to astrology as just being superstitious others say the predictions are not worth the paper they are written on. Many men and women have studied astronomy but we will look at Mother Shipton. What caused this woman to focus her life on the study of astrology? Why did she believe astrology could predict one’s character or life? Was she just passing on false information or is the universe interrelated and everything is based on these Zodiac signs? Astrology is a phenomenon that dates back to biblical days. There is an ancient legend, that Adam received the doctrines and mysteries of astrology direct from his Maker and thus by foreknowing that the earth was to be destroyed first by fire and afterwards by water. (Thompson 17) Astrology has played an important role in our civilization. Starting with Adam and even being present in today’s society. Different civilizations seemed to be practicing astrology independetely. People noticed the Sun in particular had a change on how crops grew. Many people viewed astronomy and astrology as a similar science until the 1500s. People knew by looking at the sun or what the size of the moon was when to plant crops or even when a baby was going to be born. These early astrologers were searching for their place in life. A place where they fit into the universe. They believed that every component of the universe was linked together and everyone had their own place. Every aspect of one’s life was based on the planets and the stars. Even behavior was blamed on the position of the sun! Astrology is widely practiced today. Even today most farmers have a Farmer’s Almanac. This book tells you when to plant your crops, and many people have success. Some won’t even think about planting crops without this information. This is a form of astrology, although many people do not realize it. A popular form of astrology is the Physic Friends Network. This is a 900 number you can call in to see what your sign is and how this affects you. The astrologers on the Physic Friends Network always seem to know what has happened in the past and what will occur in the future. Everyone who says they are astrologers obviously are not and it’s up to us to use our own judgment to decide. When you hear people talk about signs of the Zodiac you often Wonder what does that mean? Ancient astronomers noted that the sun makes a yearly journey across the celestial sphere, part of which is represented in the picture by the blue band. The ancient astronomers associated dates with the constellations in this narrow belt (which is known as the zodiac), assigning to each constellation of stars the dates when the sun was in the same region of the celestial sphere as the constellation. (Encarta 1999) Each Zodiac sign belongs to four different elements: Fire, Air, Earth and Water. Fire is a positive element; this element focuses on changing energy from one form to another. Air is also a positive element that is associated with the spiritual part of life. Earth on the other hand is a negative element that is solid and approves of people on earth. The last element is water this is to a negative element that tends to be mysterious. The following is a chart that will list each Zodiac sign: When you are born within a certain month you automatically are assigned a zodiac sign. For example, I was born in July: therefore, I am a Cancer. Cancer people tend to “ be great nuturers of humankind. Like rivers they flow into any vacant heart, providing a healthy heart.” (Elliott 76) Astrologers say they can predict your life through this sign but often you can be very similar to other zodiac signs. Astrologers say that the best way to explain zodiac signs is to “imagine that your divine spirit is imprisoned in an earthly form, much like animals in a cage.” They can predict what moods you will be in, what type of person you will marry or even the sports you like to play! These kinds of predictions may or may not come true. Not all astrologers can understand or interpret your true readings. Even if you do not believe in astrology, you can still have a good time. When you pay a minimal charge to find out what the future holds for you, you always want to hear good news. Although sometimes there will be bad news as well. The next idea we will look into is that the planets play a role in astrology. The sun and the moon play an important role acting as a mom and a dad. The planets tend to effect our lives in a way many of us are unaware. Each planet has its own reason for existing. Mercury for instance “is the planet closest to the sun, it plays as the communications network for the entire solar system.” (Elliott 38) Each planet has a zodiac sign which aids in the predictions. When people are born and a planet is rising this is considered to be their planet. Astrologers have mapped out what the Saturn people or the Mars people are actually like! Through many years of study and practice astrologers are able to predict futures and destines. The planets play an important role in our universe. Research has been done to prove that the weather and earthquakes can be determined through a close look at the planets. The developments are still in the first stages. The future of astrology could be significant in the predictions of dangerous hurricanes and earthquakes. These facts may aid in saving lives. Astrologers served in the king’s court in early times to predict many things. When a battle was going to take pace or even the fate of their kingdoms. Many astrologers held influential and well paid positions. The one astrologer that some people say existed in Henry VII’s time was a woman named Mother Shipton. Her fame was spread and everyone came to visit her. Her prophecies came true and she was feared throughout the land. She phropisied death and she was always correct. Mother Shipton said “All I can say is, that I fear they will prove true than most men imagine.” (Thompson 204) Everyone feared a prediction on themselves. Mother Shipton was born in “1488 in Norfolk, England, and died in 1561. She exhibited prophetic and physic abilities from an early age”.(www.newage.com.au/library/shipton.html) This was a very intriguing woman, who could predict ones future. It is rumored that she was related to the devil himself. She predicted events in her own day as well as the future. Astrology has a rich history and even dates back to the BC days. It has been said that Adam had practiced astrology and received this message from his Maker. Astrologers say they can predict: weather, babies being born, destiny, romance or when to plant crops. The predictions come from the studies of the Zodiac signs and the planets. Everyone’s life is based on your Zodiac sign. What month you are born in determines everything about you. Your bad behavior can now be blamed on the position of the sun! It seems that a lot of groups these days are trying to make a profit on their predictions. The Physic Friends Network try to capitalize on their knowledge. You can call in and get your physic reading. The sun and the moon play a huge part in determining your signs and this is how they determine their predictions. There are four grouping that each zodiac sign can be placed into: Fire, Air, Earth and Water. Fire and Air are both positive which leaves Earth and Water negative. These grouping have a specific meaning and association. Your zodiac sign will follow you throughout life and direct you in the right path. You may not always be the textbook Cancer, you could pick up a trait or two of the Scorpio grouping. Astrologers say that planets play a role in the aiding of predictions. Each planet has its own meaning and even a zodiac sign. Research has been done proving that weather and earthquakes can be predicted by observing the planets. Unfortunately, the research is still in the development stages. This research could be beneficial to all of us and could save lives. One famous astrologer was Mother Shipton from Norfolk, England. She was a woman who could predict life, death and even sickness. It was rumored that she was related to the devil himself! She was famous throughout the Norfolk area. Often respected and feared. Many of the early pioneers lead the way for astrologers in toady’s world. In closing, the paper you have just read in no way encourages or discourages astrology. Many people believe and respect this way of life. Astrology is a very complex and misunderstood subject. It requires talent and skill. The future of astrology looks bright, and will go on for a very long time.

Words: 3370