2. Yesterday an earthquake hit Haiti. Initial estimates are that “hundreds of thousands” have died. More are homeless. Consider making a contribution to assist in the recovery. Here are a few agencies that will need help: Oxfam: www.oxfamamerica.orgwww.oxfamamerica.org Red Cross:www.redcross.org Doctors Without Borders: doctorswithoutborders.org UNICEF: unicefusa.org/haitiquake unicefusa.org/haitiquake Save the Children:savethechildren.org

3. If you intend to enroll in this class, but are not yet enrolled (e.g., on waitlist): 1) Send email to Dr. Dash (tomsc@astro.indiana.edu) indicating your intention to enroll in the class. Include your name and IU email address.tomsc@astro.indiana.edu 2) Continue to attend class and participate as if you are already enrolled.

4. Stellar Birth: Adrift 1,500 light-years away in one of the most recognizable constellations, the glowing Orion Nebula and the dark Horsehead Nebula. The former is a great example of a stellar nursery.

5. Stellar death: In 1987, the brightest supernova in recent history occurred in the Large Magellanic Cloud, a companion galaxy to the Milky Way. At the center of the picture is an object central to the remains of the violent stellar explosion.

6. Homework #1 will be posted next week. There will be an announcement posted and an email broadcast concerning this homework when it is posted.

7. Class web page: www.astro.indiana.edu/~classweb/a100s26782 Homework assignments, announcements, reading assignments, etc. Consult this site on a regular basis.

8. Long, long, ago, On a hillside far, far, away…

9. Science begins with observation:

10. And now, an exercise in observation and analytic thinking… “Observed Facts” and Interpretation Science begins with observations…

11. You will be shown a sequence of images of successive full Moons (20 cycles, repeated) assembled into a video format. Working with people near you, address the following: Describe how the Moon’s appearance changes from one full moon to the next.

13. What do we see in the sky? (with the unaided “naked” eye)

14. STARSSTARS Many points of light “fixed” in relation to each other but changing location in the sky with time

15. SUNSUN Location changes on yearly cycle (typical star)

16. MOONMOON Moves relative to stars and regularly changes position and appearance over a period of a month (satellite of a planet)

17. PLANETS: Five points of light that slowly wander with respect to stars

18. MILKY WAY Cloud-like band through sky (our galaxy)MILKY WAY

19. NEBULAE Fuzzy cloud-like objects (clouds of gas, dust)NEBULAE

20. COMETS Extended objects with tails (“dirty snowballs”)COMETS

21. METEORS “Falling Stars” (rocky or metallic objects)METEORS

22. Some things are visible only with telescopes

23. PLANETARY SATELLITESPLANETARY SATELLITES: “Moons”

24. ASTEROIDSASTEROIDS: Rocky or metallic planetesimals

25. GALAXIESGALAXIES: Homes of stars, gas, dust, …

26. “home”

27. Typical Galaxy: roughly 10 11 stars Observable Universe: roughly 10 11 galaxies How much is 10 11 ?

28. McDonalds has sold over 10 11 hamburgers! hamburgers If you counted one number per second, worked an eight hour day, it would take 10,000 years to count to 10 11 !hour OR…

29. Local Group – Few dozen “nearby” galaxies Outside of Local Group, essentially all galaxies moving away from Milky Way with velocity proportional to distance! Direct prediction of uniformly expanding universe BIG BANG – Universe approx. 13 x 10 9 years old

30. Galaxies don’t like to live alone… CLUSTERS of GALAXIESCLUSTERS of GALAXIES: few to thousands of gravitationally bound galaxies SUPERCLUSTERSSUPERCLUSTERS: Clusters of clusters of galaxies

31. What is the Earth’s place in the Universe?

32. A video interlude… “The Cosmic Connection”