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Prof . Geoff Marcy

Prof . Geoff Marcy. Jupiter and Europa. Saturn and Enceladus. Textbook : The Cosmic Perspective Bennett et al . Order from Bookstore (takes a few days) to get kit for homework: MasteringAstronomy www.masteringastronomy.com Course ID: THEPLANETSFALL2012

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Prof . Geoff Marcy

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  1. Prof. Geoff Marcy Jupiter and Europa Saturn and Enceladus

  2. Textbook: The Cosmic Perspective Bennett et al. Order from Bookstore (takes a few days) to get kit for homework: MasteringAstronomy www.masteringastronomy.com Course ID: THEPLANETSFALL2012 Or get a used book, and purchase MasteringAstronomy online Reading this week and next week: Chapters 1 and 2 “Our place in the Universe “ & “Discovering the Sky” Homework: Due every Friday at 6pm Chapter 1 and Chapter 2 Assignments: due Friday Aug 31 at 6pm  Tuesday Sept. 4 @ 6pm 5% off for each wrong try. 2% for a hint.

  3. 12 Discussion Sections • All startthis week. • Review, Clarification, Homework Help. Sign up on Telebears • 101 Wed 9-10A, 265 McCone Hall: Ben Legg • 102 Wed 1-2P, 264 Evans Hall: Lea Hirsch • 103 Wed 2-3P, 264 Evans Hall: Tess McEnulty • 104 Wed 3-4P, 241 Cory Hall: Tess McEnulty • 105 Th 2-3P, 264 Evans Hall: Lea Hirsch • 106 Tu 2-3P, 264 Evans Hall: Tess McEnulty • 107 Th 11-12P, 264 Evans Hall: Ryan Turner • 108 Tu 11-12P, 264 Evans Hall: Ryan Turner • 109 Tu 12-1P, 264 Evans Hall: Drummond Fielding • 110 Th 12-1P, 264 Evans Hall: Lea Hirsch • 111 W 11-12P, 264 Evans Hall: Ben Legg • 112 Wed 12-1P, 264 Evans Hall: Drummond Fielding

  4. Observing Project #1 Two choices A) Chart the position and shape of the moon. Sketch where the moon is located relative to nearby buildings. Also sketch the shape of the moon. Mark which direction is south. Note the time and day on the sketch. Wait 2-5 days, and do it again. (Hint: the moon is up now from 8pm-2am) Turn in both sketches, with time and date of observation. Write three to four sentences about any change you saw in the position or shape. B) Sketch where the Sun sets, relative to buildings. Wait 4-10 days. Sketch where the Sun sets again. Turn in both sketches, with time and date of observation. Write three sentences about any change in the position of sunset. Did it change? What direction? By how many degrees (approx.)? (The sun has an angular size of 0.5 degrees in diameter.) Due in class, Thursday Sept. 6 1 page maximum; Handwritten is fine.

  5. Course material on bSpace:http://bspace.berkeley.edu • Syllabus • Lecture slides • Assignments: reading, homework, observing projects • Course information

  6. Last Time :: The Solar System

  7. The Solar System Inner Solar System Outer Solar System

  8. The Solar System:Sun and 8 Planets Moons, Rings, Asteroids, Comets, and Dust

  9. Milky Way Galaxy 200 Billion Stars Photo taken from Earth You Are Here

  10. Our Milky Way Galaxy Our Sun moves relative to the other stars in the local Solar neighborhood. Our Sun and the stars orbit around the center of the Milky Way Galaxy every 230 million years.

  11. Spiral Galaxies

  12. Elliptical Galaxies

  13. Irregular Galaxies

  14. The ``Local Group” of Galaxies 100,000 Light Years The Galactic Neighborhood

  15. The ``Local Group’’of Galaxies

  16. And outward… 10 Million Light Years

  17. The Universe: All matter and energy > 100 Billion Galaxies

  18. B Astronomical Numbers Best to use Exponential Notation 103 = 1000 Thousand 106 = 1,000,000 Million 109 = 1,000,000,000 Billion 1012 = 1,000,000,000,000 Trillion Also: 10–3 = 1/1000 = 0.001 Exponential notation is handy: 10N x 10M = 10(N+M) Example: 103x106 = 109 thousand million billion

  19. Interactive Quiz B How many stars in our visible Universe? 1012 (1 million million) 1018 (1 billion billion) 1022 infinite

  20. Interactive Quiz B How many stars in our visible Universe? 1012 (1 million million) 1018 (1 billion billion) 1022 infinite Number of Stars in a galaxy: ~100 billion = 1011 Number of galaxies in Universe: 100 billion = 1011

  21. B Federal Deficit each Year There are 1011 stars in the galaxy. That used to be a huge number. But it's only a hundred billion. It's less than the national deficit! We used to call them astronomical numbers. Now we should call them economical numbers. Richard Feynman

  22. B In 2012, the National Debt is $15.9 Trillion = $15.9 x 1012 U.S. Population = 311 x106 people Your Personal Debt: $15.9 x 1012 / 3.11 x 108= $5 x104 = $50,000 per person

  23. B Population of US: 300 million Cost per person: $787x109 / 3x108 = $2623

  24. B Distance, time and number : Radius of our Galaxy: 6,000,000,000,000,000,000 m = Radius of a Hydrogen atom: 0.00000000005 m= Time for one vibration of an oxygen molecule, O2: 0.00000000000001s = Age of the Universe: 430,000,000,000,000,000s = Scientific notation: 6 x 1018 m 0.5 x 10–10 m 1 x 10–14 s 4.3 x 1017s = 13.6 billion years

  25. B SI (Systeme International) Units Base units: 1 meter (m) length ~ 3.3 ft 1 kilogram (kg) mass ~ 2.2 lb 1 second (s) time

  26. B • SI (Systeme International) Units • Base units: 1 meter (m) length • 1 kilogram (kg) mass • 1 second (s) time • MKS System of units and measure Sometimes easier to derive other units from these: km, g, ms, µs, … km = 103 m kilo g = 10-3 kg kilo ms = 10-3 s milli µs = 10-6 s micro

  27. $Billion error B UNITS ARE IMPORTANT!!! Mars Climate Orbiter: Launch: 11 Dec. 1998 Orbit insertion: 23 Sep. 1999 Followed by: Loss of Communication WHY? Failed to convert from English units (inches, feet, pounds) to Metric units (MKS)

  28. B Speed of Light and Light-travel time: C = 3 x 108m/sec = 3 x 105 km/sec = 300,000 km/sec = 0.3 m/ns (1 ns = 10-9s) Light Year = 9 trillion km = 6 trillion miles Light Hour Light Minutes are unit of Distance: How far Light Travels in that interval of time 1 light second = 3 x 105 km 1 light ns = 30 cm ≈ 1 foot

  29. B How long does it take the sun’s light to reach the Earth? Distanced = 1 AU = 1.5x1011m Speed of lightc= 3x108m/s Time

  30. B Driving Curiosity Rover on Mars • How long does it take to communicate withCuriosity ?

  31. Interactive Quiz B How long does it take for radio waves (light) to reach Mars? • Less than 1 second • 1 minute • 10 minutes • 1 hour

  32. Interactive Quiz B How long does it take for radio waves (light) to reach Mars? • Less than 1 second • 1 minute • 10 minutes • 1 hour Earth-Mars distance: between 55 and 400 million km. tmin = dmin/v = 5.5×107 km / (3×105 km/s ) =1.8×102s= 3 minutes tmax = dmax/v = 4.0×108 km / (3×105 km/s ) =1.3×103s= 22 minutes

  33. A Scaled Model of the Solar System 10 Billion x Smaller Sun’s diameter: 14 x 1010 cm Reduce by 1010: 14 cm Earth diameter: 13000 km 0.13 cm Jupiter’s diameter: 150,000 km 1.5 cm Earth’s distance from Sun: 1 “Astronomical Unit” = 1 “AU” = 1.5 x 108 km 1010 Scaled Down “Sun” 14cm 1 AU ?? cm 1.5 cm 15 cm 150 cm 1500 cm Ans: 1500 cm = 15 meters

  34. G How large is the Solar System? • Let’s view it to scale • Say the Sun is the size of a large grapefruit, 14 cm (6 inches) - then:

  35. Planet Dist (AU) Scaled Dist (m) Where? Mercury 0.4 6 6 rows back Venus 0.7 10 10 rows Earth 1.0 15 15 rows Mars 1.5 22 22 rows Jupiter 5 75 3/4 football field away Saturn 10 150 1.5 football field away Uranus 20 300 Sproul Plaza Neptune 30 450 Bancroft Ave Pluto 50 750 Durant Ave Oort Cloud 50,000 5 x 105 Oakland

  36. G You Are Here: Earth’s Orbit Saturn o Jupiter o Uranus o . . 100 m Neptune o

  37. G How Far is the Nearest Star? Alpha Centauri d = 4 light years = 4 x1016 m Scales to: 4 x 106 m (~ 3000 mi) Grapefruit-sized Sun in Berkeley Nearest Grapefruit: In Washington D.C. “Sun” in S.F. “Alpha Centauri” In Washington D.C.

  38. G Powers of Ten“Cosmic Voyage”The Movie

  39. G How to deal with very large & small numbers • Develop a useful arithmetic • Exponential notation; convert between units • Visualize using a sequence of images (movie) • Use different sequences • Visualize by way of a scale model • Try different models

  40. G A Universe in motion • Contrary to our perception, we are not “sitting still.” • We are moving with the Earth. • and not just in one direction The Earth rotates around it’s axis once every day.

  41. G The Earth orbits around the Sun once every year. The Earth’s axis is tilted by 23.5º !

  42. B Looking back in time • Light, although fast, travels at a finite speed. • It takes: • 8 minutes to reach us from the Sun • 8 years to reach us from Sirius (8 light-years away) • 1,500 years to reach us from the Orion Nebula • The farther out we look into the Universe, the farther back in time we see!

  43. B TheOrigin of the Universe (1) The two simplest atoms, H and He, were created during the Big Bang. • (2) More complex atoms were created in stars. • (3) When the star dies, chemical elements are expelled into space, to form new stars and planets! Most of the atoms in our bodies were created in the core of a star.

  44. Galaxies appear to be moving away from us. • The farther away they are, the faster they are moving. • Space itself is expanding pace itself expands.

  45. B How old is the Universe? • The Cosmic Calendar • if the entire age of the Universe were one calendar year • one month would be approximately 1 billion real years

  46. B The Universe in a Day Look at the entire history of the Universe as though it took place in a single day. The present is at the stroke of midnight at the end of that day. Since it is about 13.5 billion years old, each hour will be ~0.5 billion years. A million years takes only a little over 7 seconds. The Big Bang (a dense, hot explosion) and the formation of H and He all take place in the first nanosecond. The Universe becomes transparent in about 2 seconds. The first stars and galaxies appear after about 2am. Our Galaxy forms at 4am. Generations of stars are born and die.

  47. B The Universe in a Day The Solar System does not form until 3pm. The first life (bacterial) appears on the Earth by 4pm. Our atmosphere begins to have free oxygen at 7 or 8 pm, and this promotes the development of creatures which can move more aggressively and eat each other. Life does not begin to take on complex forms (multicellular) until 10:45pm. It moves onto land at 11:10. The dinosaurs appear at about 11:40, and become extinct at 11:52. Pre-human primates appear at around 14 seconds before midnight, and all of recorded history occurs in the last 70 milliseconds. Looking to the future, we can expect the Universe of stars to go on for at least another millennium (using the same time compression factor). After that, there are other ages of the Universe (not dominated by stars), which grow colder and more bizarre, and take place on astronomical timescales…

  48. What is the Earth’s velocity about the Sun? B Radius of Orbit (1 AU): 150 x 106 km Circumference: 2 π x radius Distance around the Sun that the Earth travels: 2 π x (1.5 x 108 km) = 9 x 1011 m Earth orbits the Sun once a year: 1 yr = 3 x 107 s Velocity = Distance/Time = 9 x 1011 m / 3 x 107 s = 3 x 104 m/s = 30 km/s 110,000 km/hr or 75,000 miles/hr!

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