Famous Astronomers

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Famous Astronomers (8)


History of Astronomy

The history of astronomy(1) is quite a long one, with early astronomical discoveries dating back to ancient civilizations, such as the Mayans and the Greeks. Although much of it is no longer accepted, the influences of these discoveries are profound. At the time, astronomy was limited to that which people could see with their naked eyes. As a result, much of their astronomy was based on the solar and lunar cycles.(1)
For example, in the Mayan city of Chichen Itza(20), their pyramid called El Castillo had a serpent that descends down the side of the stairway on both the Spring and Autumn Equinoxes. The Mayans were ardent observers of the movement of the sun and other celestial bodies; El Caracol was built to mark important movements including the point at which Venus can be seen on the horizon every eight years.(20)


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Chichen Itza (10)



In the English county of Wiltshire, stands another ancient monument built to study the sky: Stonehenge(21). Believed to have been built between 3000 and 2000 B.C., Stonehenge's purpose has been contested throughout the years. Some believe it was a place for healing as well as a burial site, whereas, others cite its astronomical uses: the markings of 165 points of Stonehenge correspond with several important solar and lunar events. For example, lunar eclipses can be predicted by moving the stones in a certain way.(21)



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Stonehenge (9)



The Greek Astronomers

Although the Greeks were not the first to study astronomy, their work was very influential. For example, the philosopher Eratosthenes(12) was the first to measure the circumference(13) of the Earth. Eratosthenes’ methods in measuring were very successful as he was able to measure the circumference of the Earth to within 300 kilometers of the measurements we have today. In addition, the Greek astronomers were the first to discover that the Earth is a sphere. This was a very important discovery, as the Greeks had previously believed that the Earth was flat. In 200 BC, the Greek philosopher Aristarchus(12) was the first to suggest that the Earth revolved around the Sun. However, this statement was widely disputed and most Greeks continued to believe that everything revolved around the Sun. (1)



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Aristotle (19)


One astronomer that disputed this idea that the Earth revolved around the Sun, and said that the Earth was the center of the universe was Aristotle(12). He believed that the Earth was in motion and that all objects were fixed around the Earth. This was all based on his idea that the universe was spherical, allowing stars and planetary objects to keep their positions. In order to prove this idea, he used his observations of lunar eclipses and the Earth's shadow on the moon among other things. His perception and study of the change and motion of planetary objects was very influential in aiding other astronomers to further their understanding of the universe.(18) Furthermore, another influencial Greek astronomer by the name of Ptolemy(12) also contributed to the understanding of how planets and objects move. He did this through his work titled The Almagest (21)around 150 A.D. In The Almagest, Ptolemy describes motions of the stars and planetary paths. Based on past observations from other astronomers along with his own, he created models for ways to figure out the location of planets in the past, as well as in the future.(21)


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Ptolemy (11)



Renaissance Astronomers
The Renaissance served as one of the most influential periods in astronomical history. During this time, scientists greatly encouraged the expansion of the study of astronomy.
Beginning with Tycho Brahe,(14) a Danish astronomer, the understanding of the solar system deepened tremendously. Brahe concentrated much of his work on making specific and accurate observations of that which was happening in the sky. His discovery of atmospheric refraction allowed subsequent astronomers the ability to study planetary nuances that were previously unknown. His research was also the vehicle through which Johannes Kepler developed his theory of planetary motion, which is still accepted today.(14)

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Tycho Brahe's System of Motion (34)



Another important Renaissance astronomer was Nicolaus Copernicus(27). It was in his book, De Revolutionibus Orbium Coelestium that Copernicus revealed through mathematics, astronomy, and cosmology the reality of the solar system as heliocentric. Instead of placing the Earth at the center of the solar system, as had been widely accepted at the time, Copernicus placed the sun in the center of his model. This placement allowed physics to determine what one saw in the sky. Because of his fear of the church, Copernicus did not allow his book to be published until after he had passed away.(27)

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Nicolaus Copernicus(7)


Galileo Galilei(26) was another important Renaissance Astronomer and he is well known for the magnificent observations he made with his telescope(14). Galileo was born in 1564 and he spent the majority of his life working towards scientific discoveries. One of his largest accomplishments was his improvement of the telescope, which allowed him to locate the moons of Jupiter, and mountains on the Moon. Galileo is considered to be a Renaissance astronomer and he is well known for his controversial conviction by the Catholic Church. Galileo was very adamant about his beliefs in a Heliocentric(15), or a Sun-centered solar system and the Catholic Church believed that everything should revolve around the Earth. Therefore, the Catholic Church forced Galileo to go into isolation until his death in 1642. (2)


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Catholic Church vs. Galileo (3)



Similar to Galileo, Johannes Kepler(16) also carried a strong belief in the Copernican System. Kepler is known today for his determination that the orbits of the planets in the solar system are ellipses(17) rather than circles. Kepler also worked closely with Brahe in his studies despite the fact that these two men were known to be constantly arguing with one another. Another important scientific achievement that came out of Kepler’s career as an astronomer, are Kepler’s three laws of motion(16). The first law states that the orbits of the planets are ellipses, with the Sun located at a focus of the ellipse. This was a revolutionary notion as most people believed that planets rotated in perfect circles. The second law states that the line joining the Sun to a planet sweeps out in equal areas for equal times. Finally, Kepler’s third law states that the ratio of the squares of the orbital periods for two planets is equal to the ratio of the cubes of their semi-major axes. The fact that we still use these laws in science today, suggests that Kepler was one of the most influential astronomers of his time. (4)



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Johannes Kepler (5)


Another astronomer that further laid the foundation for others to build upon was Isaac Newton(32). Isaac Newton was an English man who was heavily involved in the formulation of laws through his knowledge of mathematics. He created the law of gravitation and the laws of motion through this knowledge. He studied many aspects of light and the colors that are incorporated in sunlight. Newton used this knowledge of light to further expand on his accomplishments. For instance, he developed a reflecting telescope(35) to deal with the problems of chromatic aberration. However, he is most noted for his three laws of motion which allowed others to further understand and develop their knowledge of motion. He presented his three laws of motion in the "Principia Mathematica Philosophiae Naturalis(33)."
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Newton (31)



Modern Astronomers

Modern astronomers have been focusing on a few different areas of study, which include dark matter and dark energy, along with stars and galaxies. Currently astronomers, in the context of contemporary research, are using new observational instruments and techniques to uncover the history of the universe. With the technology that we now possess, science is on the rise almost exponentially, especially when it comes to space exploration. Taking advantage of the modern day science, astronomers are able to further examine the sky and come closer to answering the fundamental questions that are continually debated about by science and religion. By “looking into the past,” astronomers are closer to piecing together the puzzle behind the way in which our universe was shaped. Using state of the art ground- and space-based telescopes, combined with complex computational methods and theoretical techniques, astronomers will continue to search for answers that can help to provide more details.
Modern Astronomy (36)
Modern Astronomy (36)

Most notably on this quest, is Stephen Hawking(28), a theoretical physicist who was concerned with uncovering in detail the basic laws that govern the universe. Beginning with the Big Bang Theory(29) and going as far as solving the mystery behind black holes, his research has hinted that the way the universe formed was completely determined by the laws of science. During one interview Hawking goes as far to suggest that, “that with modern space-based instruments, such as the European Space Agency's Planck mission(30), it may be possible to spot ancient fingerprints in the light left over from the earliest moments of the universe and determine how our own place in space came to be.” Using this information, they may finally figure out how this world or even galaxy arrived at its current place of residence. With the contribution of great minds like Hawking, and many more to come, the possibilities of what astronomers will uncover is endless.(28)

Dinner with Astronomers!





YouTube Video found at:
http://www.youtube.com/watch?v=j8gNpyWjrtg&feature=player_embedded (6)


Famous Astronomers Works Cited


By: Kyle Mathis, Joe Rosa, Colleen Caragher, and Melanie Albert