Lecture 1 Astron 10 Instructor: Dr. Babar Ali

1. Lecture 1 Astron 10 Instructor: Dr. Babar Ali

2. Today’s Topics • Introductions • Organization of Classes • Course Syllabus • Introduction to Astronomy & the Universe Astro 103

3. I am so new … The Adjunct’s Office • I do not yet have an e-mail • I just got a mailbox • I do not have a phone extension • I do not yet have access to the online system • I do not have set office hours yet Astro 103

4. Today’s Lecture • No hardcopy of syllabus to hand out. • Actually copy of Syllabus will be handed out next lecture on Thursday. Astro 103

5. Syllabus • Main points to be discussed today • Hardcopy at next lecture Astro 103

6. Syllabus Astronomy 1, Fall Semester, 2014 Instructor: Dr. Babar Ali Office: Center for the Sciences, adjuncts office Office Hours: by appointment Contact Information: E-mail address: TBD (This syllabus is adapted from one used by the department chair). Goals The whole of existence is vast and strange and unlike our life here on Earth. But one of the most amazing things about the Universe is that we can understand it. The method that we use to understand the Universe is called science, and this is a method that is open to everyone. Science is not just for a couple of people in a university laboratory to use. What is more, science is not just for finding out The Secrets of Creation either. It is something we all can use in our daily lives to understand the world around us. This class will focus on just that: using science to understand the world (and the Universe) around us. Textbook Jeffrey Bennett: The Cosmic Perspective Astro 103

7. Syllabus Classroom Etiquette: The whole purpose of many students coming together into one room for several hours a week is to effectively learn a set of knowledge. Disruptive behavior stops other students in the class from learning. Therefore, anything that disrupts other people from learning is unacceptable. This includes coming in late, packing up/leaving early, talking, etc. Cell Phones: Cell phones are trouble no matter which class they’re in. I expect all cell phones to be off and put away (no ring, no vibrate). If you are expecting an emergency call and speak to me before class, you can sit by the door and leave the classroom to answer it. Academic Misconduct All instructors are required to report suspected cases of academic misconduct. See Pierce’s Code of Student Conduct for the details. The most common forms of misconduct in class are copying from another student (a neighbor; texting, etc.). While students are highly encouraged to work together on homework, each student must turn in their own assignment in their own words. Cases will be resolved by removal from the class, a failing grade, and being reported to the Dean of Students for disciplinary action. Astro 103

8. Syllabus Attendance Attendance is expected and in a way will play a role in your final grade. While attendance is necessary the entire semester, it is incredibly important during the first three weeks. Because I am trying to separate the serious students from the not-so-much during this time, anyone missing a day will be dropped from the class and their seat given to someone on the lottery list waiting to join the class. If someone has been dropped they can get onto the lottery list and try and get back into the class. After the first three weeks, once the class has settled down, this policy will be somewhat relaxed. Just in general though, please consider that of the many astronomy professors I have talked to, and the thousands of students that have passed through their classes, they find that on average students that only show up for tests/quizzes and to turn in homework get a full letter grade less than those that attend every day. Astro 103

9. Syllabus Grading Your grade will be: 50% Final Exam, 25% Midterm, 20% Homework, and 5% In-class participation. The grade distributions will be: A: >85%, B: 70-84%, C: 60-69%, D: 50-59%, F <50%. So don’t panic if you get a 65% on a test. Astro 103

10. Syllabus Midterm The midterm will be an hour in length and be halfway through the semester. A green book will be required for the midterm so make sure to bring one. The midterm will have 5 short-answer questions, and one more in-depth question and will take one hour. There will be a 5 minute break following and the remaining time will be taken up with a short lecture. I will give the graded midterms back to you in one week. You may then turn them back into me one week after that with any additional work done. I will grade the extra work and add one-half the points you gain to your midterm score. Example: a midterm scores a 60% in-class. After a week working on it at home it is turned in and I judge it to be 80% (a gain of 20 points). The score that is entered into my records for this midterm is a 70%. I will post the solution to the midterm in the library so you can use it to help study for the final exam. Final Exam The final exam is scheduled by the school administration and the date is available in the schedule of classes not to mention the school paper. The final exam is cumulative. It is double the midterm: double the worth, double the length, double the time. The final exam will require a green book too. Unfortunately, because of the way finals week is scheduled, students won’t be able to go back over their final. Astro 103

11. Schedule of Lectures Astro 103

12. Definition taken from the Oxford English Dictionary, Online Edition Astro 103

13. Modern Astronomy • Is a science. • It uses the scientific method to understand the nature of the Universe. • More about that shortly • It is an application of the laws of physics to the Universe beyond Earth. • But, sometimes we use Earth as a reference. • We assume the same laws of physics are applicable everywhere in the Universe. Astro 103

14. What Astronomy Is NOT • Must not to be confused w/ Astrology – the belief system that states that people’s destiny & human affairs are correlated to the position of celestial objects in the skies. • Astrology does not use the scientific method. Astro 103

15. The Size and Scale of the Universe http://apod.nasa.gov/apod/ap120312.html Astro 103

16. Where are You? 0 To find our place among the stars, we will zoom out from a familiar scene, to the largest scales in the universe.

17. Powers of Ten • 100 meters • One meter square • 3.3 feet • A typical person is about 1 m tall

18. Powers of Ten • 101 meters • 10 meters • 33 feet • Size of a small part of a park

19. Powers of Ten • 102 meters • 100 meters • A large building.

20. Powers of Ten • 103 meters • 1000 meters = 1Km • About 0.67 miles • Golden Gate Park

21. Powers of Ten • 104 meters • 10 Km • San Francisco

22. Powers of Ten • 105 meters • 100 Km = 67 miles • The San Francisco Bay area

23. Powers of Ten • 106 meters • 1000 Km • California

24. Powers of Ten • 107 meters • North and Central America

25. Powers of Ten • 108 meters • 67000 miles • Earth is only ~8000 miles

26. Powers of Ten • 109 meters • Earth and Moon

27. Powers of Ten • 1010 meters • Orbit of the moon within the orbit of Earth during four days in July

28. Powers of Ten • 1011 meters • Orbits of Venus, Earth, and Mars • New Unit • Astronomical Unit

29. Earth Orbiting Around the Sun 0 In order to avoid large numbers beyond our imagination, we introduce new units: 1 Astronomical Unit (AU) = Distance Sun – Earth = 150 million km

30. Our Star, the Sun

31. The Sun • The Sun is a typical star. • Its diameter is about 1.39 million kilometers (roughly a million miles). • Its surface temperature is about 5500°C (10,000°F). • A detailed scientific model of the Sun tells us that it draws its energy from nuclear reactions occurring at its center, where the temperature is about 15 million degrees Celsius. Astro 103

32. Powers of Ten • 1012 meters • Within the orbit of Jupiter • About 5 AU

33. Powers of Ten • 1013 meters • The solar system • About 40 AU

34. 1-1: By exploring the planets, astronomers uncover clues about the formation of the solar system The Sun and Planets to Scale

35. Powers of Ten • 1014 meters • Our sun and the orbits of its planets

36. Powers of Ten • 1015 meters • Sol

37. Powers of Ten • 1016 meters • The Oort cloud • 10,000+ AU

38. Powers of Ten • 1017 meters • The nearest stars • About 1 Million AU

39. The Solar Neighborhood 0 New distance scale: 1 light year (ly) = Distance traveled by light in 1 year = 63,000 AU = 1013 km = 10,000,000,000,000 km (= 1 + 13 zeros) = 10 trillion km Nearest star to the Sun: Proxima Centauri, at a distance of 4.2 light years Approx. 17 light years

40. Powers of Ten • 1018 meters • Solar neighborhood. Stars within 50 light years

41. Parsec • Distance measure used more often than light year. • Distance at which an object the size of 1 AU subtends 1 arc-seconds on the sky. 3.25 light years = 1 pc Astro 103

42. Powers of Ten • 1019 meters • The stars of the Orion arm • 100s of parsecs

43. 1-3: By studying stars and nebulae, astronomers discover how stars are born, grow old and die Stars like Grains of Sand

44. Powers of Ten • 1020 meters • Our spiral arm

45. Powers of Ten • 1021 meters • The Milky Way Galaxy • Diameter ~ 80,000 light years

46. Powers of Ten • 1022 meters • The Local Group

47. 1-4: By observing galaxies, astronomers learn about the origin and fate of the universe A Galaxy

48. Powers of Ten • 1023 meters • Within the Virgo cluster • Millions of parsecs, or, Megaparsecs

49. Powers of Ten • 1024 meters • Clusters of galaxies

50. A Quasar