ASTR1010 Lecture 3 22 Jan 13. MA2 due Thursday re-read D2L>Content>MA on tutorial submission. Space News? Reminders.

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1 ASTR1010 Lecture 3 22 Jan 13 Today How the Sky Works Announcements: Need a SkyGazer CD? Come borrow one now, return Thurs If you brought a laptop, get SkyGazer running now Clickers-for-credit starts TODAY (code DC) JiTT1 scores released New to the class? Need extensions? Access code problems? Contact me ASAP! TAKE RESPONSIBILITY. Meet me outside afterward for Moon Balls proven best method for understanding lunar phases. What is the ecliptic plane? A) The plane of the moon s orbit around the Earth B) The plane of the Earth s orbit around the Sun C) The projection of Earth s equator onto the sky D) All of the above E) None of the above Big Bang Theory Theme Song! MA2 due Thursday re-read D2L>Content>MA on tutorial submission Space News? Reminders All reading assignments on syllabus! Reading happens before topics are presented in class Reading quiz questions: What moon phase is necessary for an eclipse of the Sun? Of the Moon? Why don t eclipses happen every month? What do solstice and equinox mean? When do they happen? What is stellar parallax? What is retrograde motion? Reading Reminders All reading assignments on syllabus! Reading happens before topics are presented in class Read TCP2 for Tuesday; JiTT2 Due Tuesday at 9am! Sample Ch2 reading quiz questions: What moon phase is necessary for an eclipse of the Sun? Of the Moon? What is stellar parallax? What is retrograde motion? What are circumpolar stars? What is your next assignment and when is it due?

2 The Really Big Picture Where are we? Scale Model Solar System Powers of Ten AstronomyPlace tutorial Quiz on Big Picture Basics Where do we come from? When are we? -- The cosmic calendar The elements in the Earth and in us a. Have been around literally forever b. Were all created in the big bang c. Were all created in stars d. Were created in stars and the big bang e. Are continuously created whenever planets form Created really means created, not just re-organized into different molecules or forms The elements in the Earth and in us a. Have been around literally forever b. Were all created in the big bang c. Were all created in stars d. Were created in stars and the big bang e. Are continuously created whenever planets form Created really means created, not just re-organized into different molecules or forms Where do we come from? COSMIC RECYCLING The first (and simplest) elements were created during the Big Bang When the star dies, they are expelled into space. to form new stars and planets! More complex elements were created in stars by fusion Most of the elements in our bodies were created in the core of a star! The Most Astounding Fact Neil degrasse Tyson About how old is the Universe? A. 14 thousand years B. 14 million years C. 14 billion years D. 14 trillion years E. 14 gazillion years

3 Chapter 2 Topics How old is the Universe? After this chapter, you ll be able to Explain why constellations change with time, date and location Explain sunrises, sunsets and seasons Explain lunar phases and eclipses Impress your date Ch2: Discovering the Universe for Yourself You will understand what we see in the sky - over a night, over a year, anywhere on Earth You will fully understand - and be able to teach anyone - the cause of the seasons, phases of the moon, and eclipses With SkyGazer we explore these phenomena from the inside. With the globe-light-moonball, we ll look at our model from the outside Which statement(s) is/are true? From Boulder, on a clear night 1. All stars are visible at some time on some night 2. Some stars are never visible at any time on any night 3. Some stars are always visible at any time on any night A. Only statement 1 is true B. Only statement 2 is true C. Only statement 3 is true D. Statements 2 and 3 are true E. Statements 1 and 3 are true Which statement(s) is/are true? From Boulder, on a clear night 1. All stars are visible at some time on some night 2. Some stars are never visible at any time on any night 3. Some stars are always visible at any time on any night A. Only statement 1 is true B. Only statement 2 is true C. Only statement 3 is true D. Statements 2 and 3 are true E. Statements 1 and 3 are true

4 Understanding What We See Aha! Effects of earth s rotation Sunrise, star-rise, moon-rise, planet-rise Effects of earth orbit around the sun: Seasons, motions of Sun Constellations changing with seasons Effects of moving to different places on Earth Getting Ready for SkyGazer Understanding Motions in the Sky What phase is the moon now? What time does it rise and set? What direction does it rise and set? Do stars rise and set? All of them? Do these motions depend on location? Read ch2 and get ready to explore! Understanding What We See Effects of rotation Sunrise, star-rise, moon-rise, planet-rise Effects of orbit: Seasons, motions of Sun Constellations changing with seasons Parallax? Effects of moving to different places on Earth What we see can be bewildering until we have a mental model Discovering the Universe for Yourself The circling sky: Changing constellations Different parts of the sky [SkyGazer] Different times of night [SkyGazer] Different places on Earth [SkyGazer] Different times of the year [SkyGazer, Lec] Seasons & Sun s motions [Lec, Tutorial] Precession [Lecture] The Moon [Tutorials] Phases eclipses Retrograde motion [SkyGazer, lecture]

5 The value: not in memorizing things about our solar system, but in learning to think scientifically: How to use a mental model Does the model/hypothesis match the observations? Does the model have a basis in what we already know? ( And why is that? ) Can we test the model by checking new predictions? If we had a different model, how would our observations be different? How do we know? Can t a different model/theory explain it? We will be testing your scientific thinking!!! Discussion: Motions in the Sky Orient yourself in the classroom, and visualize solar & stellar motions: Where s the north star? Which way do stars move around it? Where is the Sun now? Where did the Sun rise today, and where will it set? Where is the Moon? What is the moon s phase? Why does the Sun move in the sky over the course of a day? (rise and set) A: Earth s orbital motion around the Sun B: Earth s rotation C: both of the above are important in causing the Sun s motion over a day D: Phaeton, the charioteer, pulls it Why does the Sun move in the sky over the course of a day? (rise and set) A: Earth s orbital motion around the Sun B: Earth s rotation C: both of the above are important in causing the Sun s motion over a day D: Phaeton, the charioteer, pulls it The Stars Why do stars move in the sky, changing over the night and over the year? How does one s location on Earth affect the sky our see? SkyGazer Checklist Change location Watch motion over several nights Change timestep (speed of motion) Look in different directions, notice patterns Show reference markers: celestial equator, ecliptic Compare SkyGazer vs. the real sky!