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History Astronomy is perhaps the oldest science. Stargazing came before language, before fire. What is “our” place in the universe and how do we fit in?

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Presentation on theme: "History Astronomy is perhaps the oldest science. Stargazing came before language, before fire. What is “our” place in the universe and how do we fit in?"— Presentation transcript:

1 History Astronomy is perhaps the oldest science. Stargazing came before language, before fire. What is “our” place in the universe and how do we fit in?

2 Modern Event Calendars

3 Astronomical Event Recorded

4 Observatories a) Big Horn Medicine Wheel (Montana) b) Mayan Caracol (Mexico)

5 Big Horn The Big Horn Medicine Wheel in the Big Horn Mountains near Sheriden, Wyoming was interpreted in 1974 as an indicator of summer solstice sunrise and sunset, with other alignments for the rising of certain stars (Aldebaran, Rigel, and Sirius). Built about 1050 AD. Has 28 spokes, and is about 90 ft in diameter. About 50 similar circles exist. The oldest is in Canada (built about 2500 BC - at the same time as the Egyptian pyramids).

6 Caracol Located at Chichen Itza, Yucatan, Mexico, the Caracol Tower was built about 1000 AD. It has some solstice and equinox alignments, and also some star alignments. More interesting are the apparent alignments with Venus (one of their "gods"). Mayan tablets also mention the rising of Venus. The alignments make sense in light of the written records.

7 Caracol

8 Big Horn

9 Stonehenge Stonehenge (England) Inset displays sunrise on the summer solstice as seen from the center looking east toward the heel stone.

10 Stonehenge Consists of several concentric circles built in three periods, beginning about 2800 BC. The largest stones weigh 50 tons, and were transported from many miles away. Viewed from the center, the sun rises over the heel stone at the summer solstice. (This was first noted in modern history in 1771.) Many other alignments are verified by astronomical planetarium computer simulations.

11 Sun Dagger, Aztec Calendar Stone

12 Sun Dagger Discovered in 1977. Anasazi Indians of Chaco Canyon, New Mexico constructed a spiral rock carving on Fajada Butte. At noon on the summer solstice, a dagger of sun penetrates the center of the spiral. On the autumnal equinox, a sun dagger passes through the center of a small spiral on the left, and another passes on the edge of the large spiral. At the Winter Solstice, a big sun dagger passes on either side of the large spiral. Also marks a 19-year lunar cycle. (The spiral has 19 rings.)

13 Mounds Cahokia Mounds in southern Illinois near East St. Louis has a circle of postholes interpreted in 1970 as an astronomical indicator of summer solstice sunrise, winter solstice sunrise, and equinox sunrise. The mound-building Indians in the Mississippi Valley region began about 3000 years ago, and there were several cultures, and three successive groups of Indians there. There is much conjecture about their circles, but little organized study.

14 Ancient Astronomer (Astrologers) Arab Astronomers at work keeping the nobles informed and entertained. A mix of science and pseudo-science.

15 Astronomers and Astrologers In the ancient world Astronomers paid their bills and funded their scientific pursuits by –predicting astronomical events for nobles eclipses tides comets planetary motions –casting horoscopes –entertaining Astrology, although totally bogus, was good economics!

16 Astronomy Versus Astrology Astrology is an ancient superstition that hold that a person’s personality and actions are influenced by the positions of the sun, moon, planets, and stars at the moment of birth. In addition, astrologers claim that the daily changes in the location of heavenly bodies can influence events in our everyday lives. All of this is summarized in a horoscope, which includes a diagram of the zodiac, showing the precise positions of the heavenly bodies in their orbits. Is there any physical reason we should expect astrology to work, except that it might appeal to our needs? There seems to be no way for the various heavenly bodies to interact on the body of a baby at birth, except via gravity. The force of gravity exerted on the baby by the doctor is many times larger than that of the sun and planets. Thus, it would seem more important where the doctors and nurses stand in the room rather than the orientation of the sun, moon, mars and the earth.

17 Astronomy Versus Astrology Is there any evidence that astrology does work? Astrology has been tested many times over, and no legitimate test has proven any astrological influence on our lives. Extensive tests have searched in vain for relationships between birth date and profession, blood type, handedness, divorce rate, etc. Yes it is based on science: Positions via Celestial Mechanics It is NOT a science. It can not make accurate, verifiable predictions. NO it doesn’t influence our lives: Use it like you would flipping a coin or for entertainment along with the Sunday Funnies or fortune cookies.

18 Astronomy Versus Astrology TOP 10 10. Astronomers never try to contact dead Astrologers.

19 Astronomy Versus Astrology TOP 10 10. Astronomers never try to contact dead Astrologers. 9. Politicians wives never asked an astronomer for advice.

20 Astronomy Versus Astrology TOP 10 10. Astronomers never try to contact dead Astrologers. 9. Politicians wives never asked an astronomer for advice. 8. The positions of the stars, planets, etc. dictate an astronomer’s evening observing schedule, but they dictate all aspects of an astrologer’s life.

21 Astronomy Versus Astrology TOP 10 10. Astronomers never try to contact dead Astrologers. 9. Politicians wives never asked an astronomer for advice. 8. The positions of the stars, planets, etc. dictate an astronomer’s evening observing schedule, but they dictate all aspects of an astrologer’s life. 7. Telescopes come in a staggering array of shapes and sizes. All Ouija boards look the same.

22 Astronomy Versus Astrology TOP 10 10. Astronomers never try to contact dead Astrologers. 9. Politicians wives never asked an astronomer for advice. 8. The positions of the stars, planets, etc. dictate an astronomer’s evening observing schedule, but they dictate all aspects of an astrologer’s life. 7. Telescopes come in a staggering array of shapes and sizes. All Ouija boards look the same. 6. Carl Sagan did not have a 900 number.

23 Astronomy Versus Astrology TOP 10 5. Your VISA limit is of very litter interest to an astronomer.

24 Astronomy Versus Astrology TOP 10 5. Your VISA limit is of very litter interest to an astronomer. 4. Astronomers occasionally make accurate predictions.

25 Astronomy Versus Astrology TOP 10 5. Your VISA limit is of very litter interest to an astronomer. 4. Astronomers occasionally make accurate predictions. 3. Alcohol makes complex astronomical concepts more difficult to comprehend. It makes astrological concepts easier.

26 Astronomy Versus Astrology TOP 10 5. Your VISA limit is of very litter interest to an astronomer. 4. Astronomers occasionally make accurate predictions. 3. Alcohol makes complex astronomical concepts more difficult to comprehend. It makes astrological concepts easier. 2. Transposing two astronomical objects’ coordinates makes a huge difference. Transposing two peoples’ horoscopes makes no difference at all.

27 Astronomy Versus Astrology TOP 10 5. Your VISA limit is of very litter interest to an astronomer. 4. Astronomers occasionally make accurate predictions. 3. Alcohol makes complex astronomical concepts more difficult to comprehend. It makes astrological concepts easier. 2. Transposing two astronomical objects’ coordinates makes a huge difference. Transposing two peoples’ horoscopes makes no difference at all. 1. Astronomers believe in the truth of relativity. Astrologers believe in the relativity of truth

28 The Scientific Method

29 Iterative Logic and Creativity “Right-brain” thinking “Left-brain” thinking

30 Science Questions Science is only interested in questions that have an experimentally verifiable end. There must be a Test for wrongness or rightness. If there is nothing experimentally verifiable, there is no science. Not interested in speculations, only what can and can not happen. Beware Pseudo-Science (Astrology) Extraordinary Claims Require Extraordinary Evidence!

31 Our Place In the Cosmos Aristotle and Ptolemy Geocentric Theory (Earth Centered View) Copernicus and Galileo Heliocentric Theory (Sun Centered View)

32 Aristotle’s Perfect Spheres

33 Developed the first accurate star atlas, complete with brightness assignments. Taught the perfection of the heavens, spheres, and natural circles introduced by Aristotle. Geocentric “Earth-centered” Universe. Ptolemy

34 The Enigma of the Planets The retrograde loop of Mars. Planos ~ wanderer The retrograde loops of other planets over the course of a year.

35 Epicycles Explaining planetary motion in a geocentric model of the universe using perfect circles was not easy.

36 Geocentric Solar System This allowed the earth to be stationary in space, in the center of the universe, and would describe some of the motions of the heavens.

37 Retrograde Motion Mars Retrograde Motion Epicycles (Geocentric View)

38 Real Retrograde Motion Mars Motion (Heliocentric Theory)

39 Eratosthenes Lived in Alexandria Egypt at the height of its glory as the center of intellectual learning and knowledge in the ancient world. He learned from a friend, of a water well in Syenne Egypt, near Aswan to the south. On a certain day of the year, the city celebrates summer. On that day at noon, the sun does not cast any shadows and you can see sunlight reflected from the bottom of most wells. Eratosthenes knew that no such day existed in his town of Alexandria.

40 Models and Experimental Verification The earth is round? The earth moves? Ludicrous?! Eratosthenes Knew The moon and sun are round. During lunar eclipses, earth’s shadow on the moon is round.

41 Models and Experimental Verification How big is the earth. How fast is it going? Eratosthenes Knew The moon and sun are round. During lunar eclipses, earth’s shadow on the moon is round. Ships at sea appear mast first and disappear mast last.

42 Sailing, sailing, over the ocean blue... Eratosthenes Knew The moon and sun are round. During lunar eclipses, earth’s shadow on the moon is round. Ships at sea appear mast first and disappear mast last.

43 Sailing, sailing, over the ocean blue... Eratosthenes Knew The moon and sun are round. During lunar eclipses, earth’s shadow on the moon is round. Ships at sea appear mast first and disappear mast last.

44 Sailing, sailing, over the ocean blue... Eratosthenes Knew The moon and sun are round. During lunar eclipses, earth’s shadow on the moon is round. Ships at sea appear mast first and disappear mast last.

45 Sailing, sailing, over the ocean blue... Eratosthenes Knew The moon and sun are round. During lunar eclipses, earth’s shadow on the moon is round. Ships at sea appear mast first and disappear mast last.

46 Sailing, sailing, over the ocean blue... Eratosthenes Knew The moon and sun are round. During lunar eclipses, earth’s shadow on the moon is round. Ships at sea appear mast first and disappear mast last.

47 Sailing, sailing, over the ocean blue... Eratosthenes Knew The moon and sun are round. During lunar eclipses, earth’s shadow on the moon is round. Ships at sea appear mast first and disappear mast last.

48 Sailing, sailing, over the ocean blue... Eratosthenes Knew The moon and sun are round. During lunar eclipses, earth’s shadow on the moon is round. Ships at sea appear mast first and disappear mast last.

49 Sailing, sailing, over the ocean blue... The earth is round? Eratothenes Knew The moon and sun are round. During lunar eclipses, earth’s shadow on the moon is round. Ships at sea appear mast first and disappear mast last.

50 Hire a Runner to Step out the Distance Stadia (unit of measure ~ football field (Roman Coliseum))

51 Size of the Earth 360 0 = Circumference of the Earth 7 0 Distance from Alexandria to Syenne What is the distance from Alexandria to Syenne?

52 Earth As A Sphere Circumference of the earth = (360/7) 50,000 = 24,000 miles  For  ~ 3 and D = 2 x Radius 2  R = 24,000 R = 24,000/6 R ~ 4,000 miles Radius of the Earth

53 Scientific Analysis Eratosthenes had measured the size of the earth to within 10% of the actual value. Quite a feat. But, science is not only about answering a question (how big is the earth?), but following up on the consequences of the theory or model. If the earth is a sphere with a radius of 4,000 miles, what are the consequences?

54 Consequences Perhaps we can not believe the earth is flat. It must be a sphere. But, at least let us believe it sits motionless at the center of the universe with the stars and planets revolving around us. OTHERWISE… Distance = Speed x Time Distance = Circumference Speed = v Time = period of rotation

55 Consequences Perhaps we can not believe the earth is flat. It must be a sphere. But, at least let us believe it sits motionless at the center of the universe with the stars and planets revolving around us. OTHERWISE… Distance = Speed x Time Distance = Circumference Speed = v Time = period of rotation D = 24,000 t = 24 hours

56 Calculating Rotation Speed D = v t 2 R  = v t 2 (4,000 miles) 3 = v (24 hours)

57 Do You Feel FAST! D = v t 2 R  = v t 2 (4,000 miles) 3 = v (24 hours) 24,000 miles = v 24 hours 24,000 miles = v 24 hours v = 1,000 miles/hour

58 Predictions Spherical, Rotating Earth: Someone at the equator must move at 1,000 miles/hour. Experimental Verifications of the Rotating Earth: –Focault Pendulum –Coriolis Effect –Planetary Motions

59 DEFENDER OF COPERNICAN HELIOCENTRIC THEORY I. Craters on the Moon (imperfection) II. Sunspots on the Sun (imperfection and solar rotation) III. The Moons of Jupiter (earth is not the center of all things) IV. The phases of Venus I-III Represent Circumstantial evidence IV DNA/fingerprints, undeniable proof Galileo’s Observations

60

61 Galileo’s Phases of Venus Heliocentric Geocentric

62 Galileo’s Phases of Venus Geocentric versus Heliocentric

63 Galileo and the Inquisition

64 Heliocentric Retrograde Motion of Mars

65 Planetary Scale Model

66 Solar System Scale Model

67 Shapley’s Globular Cluster Distances

68 Ordinary Each successive discovery removes us from a special place in the universe. More and more observations indicate that we (and earth) are ordinary, even insignificant when compared to the vastness of space. We are a minor planet, around an average star, in an average galaxy.

69 A Stellar Zoo

70 Solar Neighborhood The Sun (an average star) and the stars within 4 parsecs.

71 The Milky Way

72 You Are Here

73 One Galaxy Among Many

74 A Slice of the Universe Each dot represents one galaxy.

75 Universe Scale

76 Scales and Sizes MOVIE: Powers of 10

77 Summary


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