1. Astronomy C12, Earth & Planetary Science C12, Letters & Science C70 The Planets Dione in front of Saturn and its Ring Tu, Th 11-12:30 am 100 Lewis Prof. Michael Manga Prof. Geoff Marcy

2. Professors gmarcy@berkeley.edu gmarcy@berkeley.edu Geoff Marcy 417 Campbell Hall gmarcy@berkeley.edu gmarcy@berkeley.edu Michael Manga 173 McCone Hall manga@seismo.berkeley.edu Departments of Astronomy, Earth & Planetary Science Departments of Astronomy, Earth & Planetary Science GSIs: Linda Strubbe linda@astron Nicholas McConnellnmcc@astro Arianna Gleasonaegleason@lbl.gov Karrie Weaverkarrie@eps Start Next Week) 8 Discussion Sections 1 hr each(Start Next Week) Review, Clarification, Homework Help Sign up for Section on Telebears

3. Text: The Solar System: The Cosmic Perspective Bennett et al. (2006) 4th Edition (not 3rd) Web Site on bspace: http://bspace.berkeley.edu Syllabus, Schedule & Lecture Figures (no animation) Assignments: Reading, Homework, Observing Project Class Information

4. Homework: 50% of your grade 12 assignments during semester Most questions from your text The Astronomy Learning Center (TALC): 264 Evans Time: TBA First homework set available Friday Due by Friday Feb 2 Turn in HW by Friday at noon: Box labeled Astro/EPS 12 in the basement of Campbell Hall.

5. Homework: You are encouraged to work together, but MUST turn in your own work, in your own words The graders can recognize copying, and answers found with Google Refer to the Berkeley Code of Student conduct if you are unclear about what constitutes cheating or plagiarism

6. Announcements No discussion sections this week Read Ch 1 of the text this week; Ch 2 by next First Homework Assignment: posted Friday. No Clickers

7. Last Time : :

8. The Solar System Inner Solar SystemOuter Solar System

9. Our place in the Universe Overview 13 billion Light Years

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

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

12. 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.

13. Spiral Galaxies

14. Elliptical Galaxies

15. Irregular Galaxies

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

17. The ``Local Group’’ of Galaxies

18. And outward… 10 Million Light Years

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

20. Astronomical Numbers Best to use Exponential Notation Exponential notation is handy: 10 N x 10 M = 10 (N+M) 10 3 = 1000 Thousand 10 6 = 1,000,000 Million 10 9 = 1,000,000,000 Billion Also: 10 –3 = 1/1000 = 0.001 10 3 x 10 6 = 10 9 thousand million billion Example:

21. How many stars in our visible Universe? a)10 6 (1 million) b)10 12 (1 million million c)10 18 (1 billion billion) d)10 22 e)infinite

22. There are 10^11 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 10^11 is the same as 10 11 Federal

23. The National Debt is $7.6 Trillion U.S. Population = 300 x 10 6 $7.6 x 10 12 / 3 x 10 8 = $2.5 x 10 4 $25,000 per person = $7.6 x 10 12 Calculate Your Debt: Federal Debt Trillions of Dollars Debt Total 02 03 04 05

24. 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, O 2 : 0.00000000000001 s = Age of the Universe: 470,000,000,000,000,000 s = Scientific notation: 6 x 10 18 m 1 x 10 –14 s 4.7 x 10 17 s = 14 billion years 0.5 x 10 –10 m

25. SI (Systeme International) Units Base units: 1 meter (m) length~ 3.3 ft 1 kilogram (kg) mass~ 2.2 lb 1 second (s) time  MKS System of units and measure

26. 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 = 10 3 m kilo g = 10 -3 kgkilo ms = 10 -3 smilli µs = 10 -6 smicro

27. 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) $Billion error $Billion error

28. Light takes time to travel: 3 x 10 8 m/sec = 3 x 10 5 km/sec = 0.3 m/ns (1 ns = 10 -9 s) 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 10 5 km 1 light ns = 30 cm ≈ 1 foot

29. Driving the Mars Exploration Rovers (MER) How long does it take to communicate with the rovers? NASA/JPL/Cornell

30. How long does it take for radio waves (light) to reach Mars? a)Less than 1 second b)10 seconds c)5 minutes d)1 day e)1 year

31. 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

32. A Scaled Model of the Solar System 10 Billion x Smaller Sun’s diameter: 14 x 10 10 cm (~ 10 6 miles) Scale 10 10 : 14 cm Earth diameter: 1.3 x 10 4 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 10 8 km 1 AU ?? cm Ans: 1500 cm = 15 meters 14cm 10 Scaled Down “Sun” a) 0.15 cm b) 1.5 cm c) 15 cm d) 150 cm e)1500 cm

33. How large is the Solar System? Let’s view it to scale –say the Sun is the size of a large grapefruit, 15 cm (6 inches) - then:

34. 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 10 5 Oakland

35. . 100 m Saturn Saturn o Uranus o Neptune o Jupiter o You Are Here: Earth’s Orbit

36. How Far is the Nearest Star? Grapefruit-sized Sun in Berkeley Nearest Grapefruit: In Washington D.C. Alpha Centauri d = 4 light years = 4 x 10 16 m Scales to: 4 x 10 6 m (~ 3000 mi)

37. Powers of Ten “Cosmic Voyage” The Movie

38. 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

39. What does our solar system look like when viewed to scale? How far away are the stars? How do human time scales compare to the age of the Universe? Key Issues So Far:

40. TODAY’S LECTURE Solar System Resides within our Milky Way Galaxy Ranges of distances and time are huge. Exponential notation and models are a real Help! Distance Units: 1 Astronomical Unit (AU) = Earth - Sun Distance = 93 million miles = 150 million km

41. How long does it take to send a message to a Pluto satellite when it is near Pluto?

42. What is the origin of the Universe? The two simplest atoms (H and He) were created during the Big Bang. More complex atoms were created in stars. 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!

43. 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.

44. 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…

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

46. What is the Earth’s velocity about the Sun? Radius of Orbit (1 AU): 150 x 10 6 km Circumference: 2 π x radius Distance around the Sun that the Earth travels: 2 π x (1.5 x 10 8 km) = 9 x 10 11 m Earth orbits the Sun once a year: 1 yr = 3 x 10 7 s Velocity = Distance/Time = 9 x 10 11 m / 3 x 10 7 s = 3 x 10 4 m/s = 30 km/s 110,000 km/hr or 75,000 miles/hr!

47. 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!

48. 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!

49. The Milky Way moves with the expansion of the Universe! Mostly all galaxies appear to be moving away from us. The farther away they are, the faster they are moving. –Just like raisins in a raisin cake; they all move apart from each other as the dough (space itself) expands.