The History OF ASTRONOMY

1. By Kat O’Brien and Evan Rauh The History OF ASTRONOMY

2. EARLY ORIGINS • Evidence of Astronomy has been found dating as far back as 5000 B.C. in the Babylonian, and Sumerians civilizations of Mesopotamia. • Though these civilizations have the earliest known artifacts linking to a knowledge of astronomy, ancient people all around the world were looking to the heavens as a means to organize and predict events in their lives. The time of day/night, and the change of season are just 2 examples of this. • Lets dive more deeply in to the astronomy of a few of these ancient civilizations… EXTRA (TERRESTRIAL) FACT Did you know that the Ancient Sumerians were said to be visited by intelligent life? There is evidence of this in surviving pieces of art . These artifacts depict “God Helpers” they called “annunaki” flying around in saucer shaped vessels with large, bulbous heads. Is it possible an interest in astronomy, by many ancient civilizations , was triggered by the arrival of extra terrestrial life forms?

3. Mesopotamian Astronomy Astronomy’s more common application in ancient times was Astrology, ancient people used observations of the stars, moon, and sun to reach purely objective conclusions about the earth. SUMERIAN • Sumerian Astronomy in Mesopotamia was the foundation of all other advanced astronomy. • They were the first civilization capable of accurately recording the phases of the sun and moon. - precise, accurate methods of mathematics and writing were developed • Astronomy was deeply imbedded in religious practices and beliefs.

4. Mesopotamian Astronomy 2 BABYLONIAN • The Babylonians greatly built upon the “research” of the Sumerians. • They developed a calendar that accurately predicted the change of seasons. • The Babylonian’s largest contribution to the world of astronomy was their star charts. • - Babylonian star charts are still used by astronomers as a gateway to a sky lost in history.

5. Mayan Astronomy The Mayans came to believe that the world was flat, with four corners. Each corner represented by a different colored jaguar, that held up the sky... • Not all Mayan conclusions were this outrageous. In fact, the Maya were quite accomplished astronomers. • They were fascinated with the phases of the sun, and based many important religious ceremonies around the solstice. • They identified planets (mainly Venus and Mars) in the sky, and distinguished them from the stars. • More than every other civilization, the Maya developed a very intricate calendar that predicted events far in the future EXTRA (TERRESTRIAL) FACT The Maya often depicted people in “spaceships” – highly intricate transportation vehicles. EVIDENCE OF ALIENS?

6. Ancient Egyptian Astronomy The Egyptians are a prime example of an ancient civilization using the astronomical knowledge to benefit themselves. They used the phases of the moon to predict the swell of the Nile (fishing season), and the phases of the sun to predict harvest season. They identified 36 groups of stars they called “decans”. They used their position in the sky to tell time at night, and also used these same groups of stars to align the pyramids north and west. The pyramids are aligned very accurately, the eastern and western sides run almost perfectly north, and the southern and northern sides run almost perfectly west. The Egyptians used the rising and setting of the stars to align the pyramids. EXTRA (TERRESTRIAL) FACT The Egyptians often depicted alien-like life forms in hieroglyphics. Were the pyramids REALLY built by slaves? Or someTHING else??

7. Ancient Chinese Astronomy • Ancient Chinese astronomers were, by far, the earliest, and most in depth ancient astronomers. • The Chinese were the first civilization to develop a planetarium, and use it to learn more about the world. • They were very gifted "librarians", they cataloged everything they observed and kept it for later dynasty's. This is a large reason for Chinese success in astronomy, they were able to pass knowledge on, and build on each others ideas. • They developed highly advanced technology to further their research. This technology lead to many modern innovations

8. Greek Astronomy 1 PLATO, EUXIDOS, AND ARISTOTLE • Plato, Euxidos, and Aristotle all used their knowledge of geometry to create theories about the workings of the earth and universe. • Plato proposed that the universe consisted of a series of crystal spheres that traced complex maps through the sky. • Euxidos elaborated on this idea, suggesting that the earth was in the center of all these spheres, and each sphere rotated around the earth and affected it in different ways. -The sun, moon , and stars all had fixed locations on the crystal spheres. • Plato and Aristotle took these spheres very seriously, and thought of them in actual physical form. Euxidos saw the spheres as more of a “computational device”. • Aristotle defined the spheres, and stated there were fifty five distinct spheres surrounding us. • “Plato believed the planets to be animate beings.  He argued that it was not possible that they should accurately describe their orbits year after year if they didn’t know what they were doing—that is, if they had no soul attached.”

9. Greek Astronomy 2 Eratosthenes and ARISTARCHUS Eratosthenes and Aristarchus based there work on measuring the approximate size of the earth, moon, and sun. The theories they developed, improved upon the crystal spheres theory. Keep in mind, many of these ideas were seen as radical and widely rejected. Aristarchus proposed the 24 hour rotation of the sphere around the Earth, and even that was rejected. “Aristarchus of Samos brought out a book consisting of certain hypotheses, in which the premises lead to the conclusion that the universe is many times greater than it is presently thought to be.  His hypotheses are that the fixed stars and the sun remain motionless, that the earth revolves about the sun in the circumference of a circle, the sun lying in the middle of the orbit, and that the sphere of the fixed stars, situated about the same center as the sun, is so great that the circular orbit of the earth is as small as a point compared with that sphere.” - Archimedes

10. Greek Astronomy 3 Hipparchus (2nd century BC) and Ptolemy (AD 150) • Hipparchus was the first astronomer to deeply investigate cycles and epicycles. • He created several theories that accounted for the circular movements and cycles of the sun, earth and moon. • Ptolemy accepted Hipparchus’ theories and elaborated and refined his findings. • Ptolemy wrote “the bible” of Greek (and other ancient) astronomical observations in his immense book, the “Almagest”. • This book changed the world of astronomy and made it possible for further astronomical investigation.

11. Arabic /Islamic Astronomy • Astronomy is deeply imbedded in Arabic culture, through the Islamic religion. • The Koran often references astronomical patterns in the sky. • Islamic religion requires prayer 5 times a day, based on the position of the sun. • Certain stars were used as guides to make sure they were praying in the direction of the Mecca. • Arabic astronomers refined the Greek “astrolabe”, a certain kind of ancient compass that used the position of stars, and developed the “sextant” which became vital in European navigation around the globe.

12. ORIGINS OF MODERN ASTRONOMY Copernicus, Galileo, Kepler, and Newton

13. COPERNICUS (1473-1543) • Copernicus' first big theory was somewhat "piggybacked" off of Claudius Ptolemy's theory (the Ptolemic Theory) that "the earth was a fixed, inert, immovable mass, located at the center of the universe, and all celestial bodies, including the sun and the fixed stars, revolved around it." • Copernicus came to reject this earthly egotistical belief, and proposed that the SUN was in the center of the universe and the earth revolved around IT.

14. Copernicus continued… He developed the HELIOCENTRIC MODEL • He created a concept of the universe where the distances of the planets from the SUN bore a direct relationship to the size of their orbits. • Copernicus' discoveries influenced every astronomer after him. • This time in astronomical science is called the COPERNICAN REVOLUTION.

15. GALILEO (1564-1642) • Often called the “father of modern observational astronomy” • Galileo made extremely significant advances in modern astronomy. Which include- • Improvements to the telescope • Paved the way for acceptance of the heliocentric system

16. Galileo continued… • The phases of Venus • Showed its revolution around the sun • The 4 largest moons of Jupiter • Proved that there is multiple centers of motion in the universe • Sunspots • Proved the imperfection of the “heavens

17. KEPLER (1571-1630) • He is best known for his Astronomia Nova (The New Astronomy) written in 1609 • This paved the way and was a foundation for Isaac Newton's Universal Gravitation. • Did fundamental work in the field of optics. He improved the refracting telescope. • His most important contribution to astronomy however was the discover of elliptical orbits

18. Kepler continued… • Kepler’s three laws of planetary motion are • The orbit of every planet is an ellipse with the Sun at one of the two foci. • A line joining a planet and the Sun sweeps out equal areas during equal intervals of time. • The square of the orbital period of a planet is directly proportional to the cube of the semi-major axis of its orbit.

19. NEWTON (1643-1727) • Newton was one of the most prominent physicists of his time if not of the renaissance • He created the three laws of motion which set a base for all sciences to come. • Also is credited with the invention calculus • To astronomy specifically Newton made the theory of Universal Gravitation based on Kepler's publications and an apple.

20. Newton continued… • A visit by Sir Edmund Halley re-inspired Newton to astronomy and committed him again to making new discoveries • Newton’s discovers to optics were also very important to astronomy • Newton used prisms and discovered that white light is a mix of primary colors he made a new telescope that increased magnification through several mirrors.

21. Post-Newtonian Astronomy(mid 1700’s-late 1800’s) • Several important discoveries were made such as • Asteroids • Neptune • Parallax • Spectroscope • And Star Catalogs • In the 19th century astronomers began to apply other sciences and math to discover new things.

22. Post-Newtonian Astronomy continued… John Couch Adams was among important 19th century astronomers he discovered Neptune. He discovered the planet by observing the orbit of Uranus and concluding that there must be another planet in the solar system. This is further example of the use of other sciences and math in the new discoveries of astronomy.

23. Modern Astronomy

24. EINSTEIN (1879-1955) • Einstein published the theory of relativity and it forever changed the course of physics and astronomy forever. • The theory of relativity solved many problems of astronomy and Einstein's day and continues to help solve issues today because of its theoretical properties.

25. HUBBLE (1889-1953) Hubble was an influence in the construction in what was the largest ground based telescopes in the world. Hubble made the discovers of other galaxies beyond the milky way he’s theorys also reinforced the big bang and ushered in a new age of astronomy and led to the discoveries of modern astronomy.

26. NASA Since 1958 when president Eisenhower started NASA it has made strides in the exploration of space. Landing the first men on the moon, exploring mars, and making discoveries about other planets is but a page of a long history book about NASA. NASA continues today to make plans and execute them to continue learning about space and our place in it.

27. THE FREAKIN END