Unit 11: Gravity & the Solar System

Transcription

1 Unit 11: Gravity & the Solar System Inquiry Physics Historical development Kepler s Laws Newton s Universal Gravitation Next

2 11: Gravity & the Solar System Historical development Eudoxus & Aristotle Ptolemy Copernicus Pope Gregory XIII Galileo Brahe Kepler Newton Einstein Index Next

3 11: Gravity & the Solar System Historical development Name Era Location Achievement Eudoxus & Aristotle 300 BCE BCE Greece Geocentric model with concentric crystal spheres; orbits are circular with epicycles (circles on circles) Index (click thumbnails to view large images & movies) Next

4 11: Gravity & the Solar System Historical development Name Era Location Achievement Ptolemy 100s Egypt Developed most accurate version of geocentric model in his Almagest, with 1000-star catalog Index (click thumbnails to view large images & movies) Next

5 11: Gravity & the Solar System Historical development Name Era Location Achievement Copernicus Early 1500s Poland Developed a heliocentric model, but orbits still circular with epicycles Index (click thumbnails to view large images & movies & applets) Next

6 11: Gravity & the Solar System Historical development Name Era Location Achievement Pope Gregory XIII Late 1500s Italy Ordered calendar fix: 10 days omitted in 1582 and 3 Julian leap days are omitted every 400 years (England and its colonies did not adopt this calendar until 1752) Index Next

7 11: Gravity & the Solar System Historical development Name Era Location Achievement Galileo Mid 1600s Italy Supported Copernican model with telescopic observations in The Starry Messenger; persecuted by religious authorities Index (click thumbnails to view large images & applets) Next

8 11: Gravity & the Solar System Historical development Name Era Location Achievement Brahe Late 1500s Denmark Used parallax to show supernova & comet out among the spheres; collected 20 years of incredibly accurate nakedeye observations Index (click thumbnails to view large images & applets) Next

9 11: Gravity & the Solar System Historical development Name Era Location Achievement Kepler Early 1600s Germany Analyzed Brahe's data to discover 3 laws of planetary motion Index (click thumbnails to view large images) Next

10 11: Gravity & the Solar System Historical development Name Era Location Achievement Newton Late 1600s England Explained all of Kepler s Laws with a single equation: F g = Gm 1 m 2 d 2 Index (click thumbnails to view large images & applets) Next

11 11: Gravity & the Solar System Historical development Name Era Location Achievement Einstein Early 1900s Switzerland, Germany Explained gravity as a warp in the spacetime continuum in his General Theory of Relativity Index (click thumbnails to view large images & movies) Next

12 11: Gravity & the Solar System Kepler s Laws 1. Planets move in ellipses with the sun off-center at one focus. (click to enlarge) Index Next

13 11: Gravity & the Solar System Kepler s Laws 1. Planets move in ellipses with the sun off-center at one focus. 2. Planets sweep out equal areas in equal time, so they speed up when closer to the sun. (click to enlarge) (click for simulation) Index Next

14 11: Gravity & the Solar System Kepler s Laws Index 1. Planets move in ellipses with the sun off-center at one focus. 2. Planets sweep out equal areas in equal time, so they speed up when closer to the sun. 3. The square of a planet s period is directly proportional to the cube of its average orbital radius. (click to enlarge) (click for simulation) (click to enlarge) Next

15 11: Gravity & the Solar System Newton s Law of Universal Gravitation NASA J-Track 3D satellite tracking International Space Station Voyager Mission Exosolar Planets Index Next

16 Unit 11: Gravity & the Solar System All images, videos, simulations, and other resources used and linked to in this presentation are being utilized under the educational fair use doctrine of United States copyright law. Inquiry Physics This presentation is Creative Commons licensed for free distribution for non-commercial use when attributed to Granger Meador Index

17 Greek Geocentric Model Return

18 Return Epicycles create retrograde motion in a geocentric system

19 Return Excerpt of Greek translation of Ptolemy s Almagest on the orbit of Mercury

20 Return The Ptolemaic Model

21 Nicholas Copernicus, who proposed a suncentered system Return

22 Excerpt from On the Revolutions of the Heavenly Spheres by Copernicus Return

23 Return Retrograde motion is actually due to varying orbital speeds around the sun

24 Galileo Galilei supported a sun-centered system Return

25 Two of Galileo s telescopes Return

26 Return Moon sketches in Galileo s The Starry Messenger

27 Return Galileo at the inquisition (Relevant Scripture)

28 Psalm 93:1 - "The Lord reigns, he is robed in majesty; the Lord is robed in majesty and is armed with strength. The world is firmly established; it cannot be moved." Psalm 104:5 - (Speaking of God.) "He set the earth on its foundations; it can never be moved." Ecclesiastes 1:5 - "The sun rises and the sun sets, and hurries back to where it rises." Joshua 10: (Joshua prays to have sun and moon stand still.) "The sun stopped in the middle of the sky and delayed going down about a full day." Habakkuk 3:11 (Habakkuk prays.) "Sun and moon stood still in the heavens at the glint of your flying arrows, at the lightning of your flashing spear." Return Galileo at the inquisition (Relevant Scripture)

29 Tycho Brahe, who collected reams of data on stars and planets Return

30 X-ray image of the supernova of 1572 Return

31 Brahe s plot of the trajectory of the comet of 1577 across the crystal spheres Return

32 Brahe s Uraniborg Castle Return

33 Brahe s Quadrant at Uraniborg Return

34 Brahe s Stjerneborg Observatory (Modern-Day) Return

35 Brahe s Stjerneborg Observatory Today Return

36 Johannes Kepler, who discovered 3 laws of planetary motion Return

37 Two of the thousands of pages from Kepler s years of calculations on the orbit of Mars Return

38 Return Comparing the accuracy of the Copernican vs. Keplerian systems

39 Isaac Newton, who linked the heavens and earth with his equation for gravity Return

40 Return Woolsthorpe, where Newton supposedly saw the apple fall

41 Albert Einstein, when he was a teenager pondering what it would be like to ride a beam of light Return

42 Return Simulation of a black hole passing in front of a distant galaxy, acting as a gravitational lens

43 Galaxy cluster in center of image is a lens creating many distorted images of a distant blue galaxy in a ring around it Return

44 Return How the two foci are used to draw an ellipse

45 y 3 α x 2 r 3 α T 2 Return

46 International Space Station, photo taken from a space shuttle in December 2006 ISS Tracking Return

47 Quit Voyager A Famous Use of Newton s Law: Two Voyager probes were launched in 1977, carrying cameras and other sensors to the outer gas giants. More Voyager

48 Quit Voyager The two Voyager space probes show the utility of Newton s equation. They were launched in 1977 and coasted by planet after planet, steered by the gravity of each successive planet as calculated years previously. More Voyager

49 The Voyager probes gave us our first close-up views of Jupiter, Saturn, Uranus, and Neptune. These gas giants dwarf the Earth. Quit Voyager More Voyager

50 Quit Voyager On the left, the moon Io is above Jupiter s Great Red Spot, which has swirled for over 300 years and is larger than Earth. Over to the right is the moon Europa. More Voyager

51 Quit Voyager Io is volcanic, spewing sulfur, and has mountains up to 52,000 feet high. More Voyager

52 Quit Voyager Icy Europa, in contrast to Io, is the smoothest object in the solar system and probably has a buried liquid water ocean. More Voyager

53 Quit Voyager Saturn s rings are mostly ice and dust. More Voyager

54 Voyager revealed that one of Saturn s outer rings is maintained by two shepherd moons, one on each side. Their gravity acts to sweep up particles to maintain the ring. Quit Voyager More Voyager

55 Quit Voyager Uranus looked almost featureless, but Voyager could detect cloud patterns. The planet is tipped over on its side with one pole always at high noon and the other in perpetual darkness. More Voyager

56 Quit Voyager Miranda is a moon of Uranus. It is about half water ice and half rock, with very odd features that may be upwellings of ice. More Voyager

57 Quit Voyager Neptune had an Earth-sized dark hurricane in progress during the flyby. The Hubble Space Telescope showed it had disappeared by 1994, but a similar storm then formed in the opposite hemisphere. More Voyager

58 Triton is Neptune s largest moon and features ice volcanoes. Quit Voyager More Voyager

59 Quit Voyager The pale blue dot is Earth as seen by Voyager 1 in 1990 as it left the solar system. More Voyager

60 Positions of Voyager 1 and 2 in October Voyager 1 is now over 100 times farther from Sol than is Earth, headed out at over 38,000 mi/h. Even at that speed the spacecraft would take tens of thousands of years to reach another star. Quit Voyager More Voyager

61 Newton s Law allows scientists to watch the shifting light from a star and deduce the approximate mass and location of large planets since their gravitational pull makes the star wobble. Return