Aristarchus

Aristarchus **Intro:**


 *  Aristarchus was a Greek astronomer and mathematician from the island of Samos in the eastern Agean Sea, near Turkey. He lived from about 310 bc. to 230 bc. ("Aristarchus" 662) He studied, worked, and lived in Alexandria, Egypt. He was a pupil of Strato. ****He is most known for making great advances in science and mathematics that effected the modern and ancient, including his heliocentric theory, his calculations to find the distances between the earth,moon,and sun and his work with lunar eclipse and shadows. **



**Heliocentric Theory:**
 *  He was the first to state that the earth revolves around the sun, proposing the heliocentric model. (Nardo 37) No one in science believed his theory during his time period, and they thought he was ludicrous. Everyone believed that the earth was the center of the universe, and the planets, sun and moon revolved around the earth. That is called the geocentric model. ****("Heliocentric Model") ****Geocentric is derived form the Greek words "Geo" meaning earth, and "Centric" meaning center. Heliocentric is derived from the Greek words "Helio" meaning sun, and "Centric" again meaning center. ("History of Aristarchus of Samos") The heliocentric model did not gain popularity until the 1500s. Great astronomer Nicolaus Copernicus built on Aristarchus' idea, and published his works. Even then it was dangerous, Copernicus published his theories on his deathbed. ("Heliocentric Model") **





**On the Sizes and Distances of the Sun and Moon:** In addition, Aristarchus figured out how to measure the relative distances from the sun, moon, and earth. ("Aristarchus 310-230 B.C.") When the moon is exactly half full, the angle E-M-S (Earth-Moon-Sun) must be exactly 90 degrees. ("Aristarchus 310-230 B.C.") That being the case, a measurement of the angle E-M-S when the moon is half full will give the ratio of the Earth-Moon distance to the Earth-Sun distance. ("Aristarchus 310-230 B.C.") The ratio of the distance ES to EM (Earth-Sun to Earth-Moon) is greater than 18 to 1 and less than 20 to 1 ( "Aristarchus of Samos")

Also Aristarchus figured out how to measure the distance and sizes of the Sun and Moon. He decided that the sun was so much bigger than the moon, he concluded earth therefore must revolve around the sun. ("Aristarchus 310-230 B.C.")

He also concluded that the sun is 300 times the size of earth. He demolished the theory that the sun was the size of Greece.

In his book, On the SIzes and Distances of the Sun and Moon, he introduced **six hypotheses.**  **1.**That the moon receives light from the sun.  **2.** That the earth has a relation of both point and center to the sphere [of revolution] of the  moon.  **3.** That whenever the moon appears to us divided in half, the greatest circle separating the  shadowed and bright [parts] of the moon inclines to our sight.   **4.** That whenever the moon appears to us divided in half, then it is away from the sun less  than a quadrant by one-thirtieth of a quadrant.  **5.** That the width of the [earth's] shadow is that of two moons. <span style="display: block; font-family: Arial,Helvetica,sans-serif; font-size: 110%; text-align: left;"> **6.** That the moon subtends a fifteenth part of a sign of the zodiac. <span style="display: block; font-family: Arial,Helvetica,sans-serif; font-size: 110%; text-align: left;"><span style="color: #808080; display: block; font-family: Arial,Helvetica,sans-serif; font-size: 110%; text-align: left;">**("Aristarchus On the Sizes and Distances of the Sun and Moon")**

<span style="font-family: Arial,Helvetica,sans-serif; font-size: 110%;"> He also introduced 18 propositions, but these **three propositions** are the most well known

<span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;"> **1.** The distance of the sun from the earth is greater than eighteen times, but less than twenty times, the distance of the moon from the earth. <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;"> **2.** The diameter of the sun has the same ratio (greater than eighteen but less than twenty) to the diameter of the moon. <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;"> **3.** the diameter of the sun has to the diameter of the earth a ratio greater than 19 to 3, but less than 43 to 6.
 * <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">("Aristarchus of Samos") **



<span style="background-color: #ffffff; color: #0000ff; font-family: Arial,Helvetica,sans-serif; font-size: 25px;">**Lunar Eclipse:**
 * Next, Aristarchus aslo figured out how to measure the size of the moon. ("Aristarchus 310-230 B.C.") During a Lunar Eclipse he measured the duration of time between the moment when the edge of the moon first entered the umbra and the moment when the Moon was first totally obscured. **** ("Aristarchus 310-230 B.C.") He derived the Moon's distance from the duration of a Lunar Eclipse. ("The Moon's Distance--1") Later on Hipparchus found an independent method. **** (The Moon's Distance--1) Also he believed that in the longest Lunar Eclipse possible, two moons fit in the Earths shadow. ("Lunar Eclipse") **

**Importance on Greece:**
 * Lastly, Aristarchus has made a huge impact on Greek astronomy and mathematics. He changed the science world forever.** **<span style="background-color: #ffffff; font-family: Arial,Helvetica,sans-serif;">("Greek Science after Aristotle.") ****<span style="background-color: #ffffff; font-family: Arial,Helvetica,sans-serif;">His heliocentric theory, his calculations to find the distances between the earth,moon,and sun and his work with lunar eclipse really impacted Greek science. ("Greek Science after Aristotle.") He effected Greece because he made tremendous astrological discoveries and used mathematics to support his hypotheses and propositions. **


 * Conclusion: **
 * All in all, Aristarchus made many stupendous remarks throughout history.** **<span style="background-color: #ffffff; font-family: Arial,Helvetica,sans-serif;">From his great achievement of the heliocentric theory, to his calculations to find the distances between the earth,moon,and sun, and his work with lunar eclipse and shadows, the world has really changed. Aristarchus had powerful background information to conclude his evidence. Without Aristarchus the world may not know phenomenal information we know today. He is one of the worlds greatest scientist whose name will live on forever. **

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 * Correction on video:** Aristarchus is from **SAMOS** not Samothrace. They are two completely different islands in the Agean Sea.

<span style="background-color: #ffffff; font-family: Arial,Helvetica,sans-serif; font-size: 25px;">Works Cited

Author Unknown. //"History of Aristarchus of Samos"// share2.esd105.wednet.edu []

http://www.astro.cornell.edu/academics/courses/astro201/aristarchus.htm
 * Author Unknown. //"Aristarchus (310-230 B.C.)"// astro.cornell.edu**

<[]>
 * Riley, Kristen.** //**"Aristarchus of Samos**"// perseus.mpiwg-berlin.mpg.de

[]
 * Author Unknown. //"Aristarchus on the Sizes and Distances of the Sun and Moon"// www.russellcottrell.com**

[]
 * <span style="background-color: #ffffff; font-family: Arial,Helvetica,sans-serif;">Author Unknown.//"Heliocentric Model."// Universetoday.com **
 * (June, 2009)**

http://www-spof.gsfc.nasa.gov/stargaze/Shipprc2.htm
 * Dr. David P. Stern. //"The Moons Distance--1."// Nasa.com**
 * (September, 2004)**

http://galileoandeinstein.physics.virginia.edu/lectures/archimedes.htm (1995)
 * Michael Fowler ("Greek Science After Aristotle.") Greek Science.com**

http://share2.esd105.wednet.edu/jmcald/Aristarchus/lunar.html
 * Nate, Steve, Brian. //"Lunar Eclipse."// Lunar Eclipse.com**


 * Nardo, Don. Ancient Greece. United States of America: Lucent Books 1994**


 * <span style="background-color: #ffffff; font-family: Arial,Helvetica,sans-serif;">Smith ****<span style="background-color: #ffffff; font-family: Arial,Helvetica,sans-serif;">, Mark. "Aristarchus." World Book. 2008 ed. 2008 **