ASTR178 Other Worlds Week 1, August 2

1. ASTR178Other WorldsWeek 1, August 2 A/Prof. Orsola De Marco orsola.demarco@mq.edu.au http://www.physics.mq.edu.au/current/undergraduate/units/ASTR178/

2. ASTR178 structure • 7 weeks, 21 hours for the Solar System (by Orsola De Marco) • 3 weeks on the details of the Sun and Solar System formation (by Andrei Gilchrist) • 3 weeks on extrasolar planets (by Mark Wardle)

3. Assignments (25%) • 3 assignments handed to students via website returned • via collection boxes. • Content of assignments discussed in class on following Monday upon request.

4. Practical (10%) • There is one practical posted on the website. • You can do it in your own time on any clear night between two specified dates • There is a minimum requirement of 5 observations between August 24th and September 11th • Due in on September 11 • You do not need to go to the Observatory, but we • will reserve two evenings for you to visit if you wish

5. Tutorials (15%) • Tutorials start week 2. Check what group you are in, andin which weeks and day your group goes to tutorial. Eachstudent goes to only 4 tutorial classes. • Tutorial class 1: • Discuss the lay out of a 5 minute presentation, techniques and technology to present and topics. • Tutorial class 2-4: • Present or listen to the presentations on a topic of your choice with relevance to this course.

6. Exam (50%) • Regular 3 hour exam. • Format likely some multiple choice, some short answers.

7. Office hours • Office Hours: • best way to contact me: e-mail orsola.demarco@mq.edu.au • Second best, make an appointment via e-mail. • Third best come to my office right after class. • If you really must, come any time. • READ YOUR UNI E-MAIL!!!!!!!!!!! It is the way I talk to you. Not reading your e-mail is no excuse not to have heard from me (check your unit e-mail works – did you get my • test message on 30 July 2010?)

8. For me to know … • Raise your hands if: • You are a Physics of Astronomy Major • Have you taken an Astronomy course before?

9. A sense of place

10. A sense of history

11. A sense of heritage

12. The Big Picture • Astronomy to create a sense of belonging that has a wider meaning. • Take a look at the short essay by Sandy Faber in the course book “Universe”.

13. Course Outline The Solar System in context and the celestial sphere Why the night sky looks the way it does. Early observers and the scientific method. The terrestrial planets: Earth The terrestrial planets: Mercury, Venus and Mars. The gas giants: Jupiter, aurorae and tides. The gas giants: Saturn, Uranus and Neptune and their rings.

14. In this class • Space and time: sizing up the Universe. The Solar System in context • Units • Angular separations and sizes • What are constellations • Earth spin, daily motion, night and day, timezones. • Earth Orbit around the Sun, yearly motion, differentstars appear overhead on different months. • The celestial sphere, north and south, the nightly motion of stars. • Latitude and longitude on Earth and how to tell Latitude by the stars

15. Units of the Universe (length) • The Scientific notation: • 1 = 100 • 10 = 101 • 100 = 102 • 100,000 = 105 • When using cm, you see a lot of, e.g., 1013! • Units of the Cosmos: • Solar Radius (Ro) • The astronomical unit (AU) • light years • parsec (=3.26 ly; pc) • centimeter (!)

16. Units of the Universe (time) • The Scientific notation: • When using the second, you see a lot of, e.g., 109 yr = 1 Gyr • Units of the Cosmos: • Year • Second

17. Units of the Universe (mass) • The Scientific notation: • When using the gram, you see a lot of, e.g., 1033 gr = 1 Msun • Units of the Cosmos: • Solar masses • Jupiter masses • Earth masses • Gram

18. And while we are at it … • prefix multipliers:10 = deca100 = hecto1000 = kilo (K)1,000,000 = 106 = million = mega (M)109 = billion = giga (G)1012 = triollion = tera (T)1015 = million trillion (?) = peta (P)(exa zetta yotta)

19. And since we are having so much fun…. • prefix multipliers:0.1 = deci0.01 = centi0.001 = milli (m)0.000001 = 10-6 = a millionth = micro ()10-9 = a billionth = nano (n)10-12 = a triollionth = pico (p)10-15 = a millionth trillionth (?) = femto (f)(atto zepto yocto)

20. Another tool of the trade:angular separations

23. The scales of the Universe

24. Earth • Radius:6357 - 6378 kmor 6.4 x 108 cm(Concept of approximation)

25. Sun • Radius696,000 kmor 6.96 x 1010 cmor 1 Ro • ~100 x Earth

26. Jupiter • Radius69,911 kmor 6.99 x 109 cmor ~0.1 Ro • ~10 x Earth

27. Solar System • Radius (Pluto)40 AU6.0 x 109 km6.0 x 1014 cm • 40 x Earth-Sun

28. Our Galaxy • Radius~15,000 pc or 15 kpc4.6 x 1022 cm • 7.7 x 107 x SS

29. Other Galaxies • LMC: 50 kpc • SMC: ~60 kpc • M31: 2.5 Mpc • Virgo Cluster: 18 Mpc

30. The Solar System in context

31. The Solar System in context

32. Timescales • Supernova implosion (last phases): seconds. • Planetary orbits: days … years … decades. • Lifetime of the Sun: 10 billion year. • Lifetime of a 100 solar mass star: few million years. • Age of the Universe 13.7 billion years.

33. Orienting yourself in the night • The first thing you need to do in order to start understanding our place in the Universe is to look up!

34. The Constellations • Stars in a constellations are not grouped in space, they are close because of chance alignment.

35. Constellations Names and the Zodiac • Many constellations were named by the Greeks (including some southern ones which were more northern 2000 years ago). • Constellations names are usually Latin (e.g., Centaurus). • Stars in a constellation are called with Greek lettersaccording to their brightness (a being the brightest), followed by the constellation name in the genitive (e.g.,a Centauri, also abbreviated a Cen). • The horoscope…

36. The day: The spin of Earth

37. The day: The spin of Earth

38. The year: The orbit of Earth

39. The night sky over the year

40. The night sky over the year

41. The celestial sphere is an imaginary sphere centered onthe Earth, whose poles are the same as the Earth’s polesand whose equator is the projection of Earth’s equator.

43. The North Celestial Pole

44. The South Celestial Pole • To find South at night, look for the South celestial pole and draw a line down to your horizon. That is South.

45. At the North Pole: how do stars move during the night?

46. And at the Equator?

47. And where is this observer?

49. Latitude and Longitude • What is the reference frame? • Latitude: equator • Longitude: the Greenwich meridian.

50. Measuring Latitude • Your latitude North/South • is the same as the altitude • of the North/South celestialpole (easy to measure in theNorth, where Polaris marksthe spot!)