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1. For instructors’ eyes only… You may be surprised to learn… …that over 25% of all undergraduate students do not utilize their required course materials. …student retention is dropping nationwide and while the higher education community has done a remarkable job of opening the doors of college to more and more students, we have not seen equal strides in the number of students who actually complete four-year degrees.(Education Trust, 2004) See the next slide on what you can do… Instructor: Course/Section:

2. For instructors’ eyes only… • What you can do… • The top factors motivating a student to use their adopted books all involve whether the material is immediately used, referred to, or assessed from in the classroom. • Please take a few minutes the first day of class to explain and demonstrate why you adopted your book and accompanying technology. • The next few slides show the book, technology products, and messaging to students that indicates they will be responsible for the content. Feel free to customize the information or delete from your slide set. Instructor: Course/Section:

3. Michael Seeds –Astronomy: The Solar System and Beyond, 5th Edition This is your required course material You will need this material for: - tests and quizzes - homework and reading assignments Instructor: Course/Section:

4. Why you need to use the new edition… Astronomy is changing rapidly! The new fifth edition is fully updated to reflect the exciting developments in astronomy, including images from the surface of Titan, gamma ray bursts, volcanism on icy moons, the Kuiper Belt and the status of Pluto, dark energy, the search for water on Mars, supernova explosions, extra solar planets, and much more. Instructor: Course/Section:

5. Your ticket to success! • Featuring instant access to online resources selected by your instructor to help you succeed in the course, including: • ThomsonNOW…Personalized Study including quizzes and animated versions of key figures from the text! • Virtual Astronomy Labs… 20 online, interactive labs focusing on the most important concepts in astronomy. REGISTER FOR 1PASS TODAY at www.thomsonedu.com/login ! Instructor: Course/Section:

6. Improve your grade! • ThomsonNOW is a powerful, online learning tool that helps you assess your unique study needs, and is available with each new copy of Seeds - Astronomy, 5th edition! • After taking a diagnostic pretest, you are given a personalized learning plan that links you to the text and the interactive animations! • Post-Tests assess student mastery of core chapter concepts; results can be emailed to the instructor! REGISTER TODAY at www.thomsonedu.com/login ! Instructor: Course/Section:

7. Interactive exercises that complement and enhance the topics in the text • Students can turn in labs online or print for homework assignments • Quizzes at the end of each lab help you test your understanding of key concepts REGISTER TODAY at www.thomsonedu.com/login ! Instructor: Course/Section:

8. Astronomy:The Solar System and Beyond 5th edition Michael Seeds

9. “The Southern Cross I saw every night abeam. The sun every morning came up astern; every evening it went down ahead. I wished for no other compass to guide me, for these were true.” - CAPTAIN JOSHUA SLOCUM Sailing Alone around the World Chapter 2

10. The night sky is the rest of the universe as seen from our planet. When you look up at the stars, you look out through a layer of air only a few hundred kilometers deep. Beyond that, space is nearly empty, and the stars are scattered light years apart.

11. Here, you will begin your search for the natural laws that govern the universe by trying to understand what the universe looks like.

12. As you read this chapter, keep in mind that you live on a planet. Stars are scattered in the void all around you, most very distant and some closer. Earth rotates on its axis once a day. So, from your viewpoint, the sky appears to rotate once around you each day. Not only does the sun rise in the East and set in the West, but so do the stars. This apparent motion is caused by the rotation of our planet.

13. The Stars • On a dark night, far from city lights, you can see a few thousand stars in the sky.

14. The Stars • The ancient astronomers organized what they saw by naming stars and groups of stars. • Some of these names survive to this day.You may know a few of these groups of stars as constellations.

15. All around the world, ancient cultures celebrated heroes, gods, and mythical beasts by naming groups of stars after them. You should not be surprised that the constellations do not look like the creatures they represent any more than Columbus, Ohio, looks like Christopher Columbus. The constellations simply celebrate the most important mythical figures in each culture. Constellations

16. The constellations named within the Western culture originated in Mesopotamia over 5,000 years ago. Other constellations were added by Babylonian, Egyptian, and Greek astronomers during the classical age. Of these ancient constellations, 48 are still in use. Constellations

17. To the ancients, a constellation was a loose grouping of stars. Many of the fainter stars were not included in any constellation. Regions of the southern sky, not visible to the ancient astronomers of northern latitudes, were not identified with constellations. Constellations

18. Constellations • Constellation boundaries, when they were defined at all, were only approximate. • So, a star likeAlpheratz could be thought of as part of Pegasus or part of Andromeda.

19. Constellations • In order to correct these gaps and ambiguities, astronomers in recent centuries have added 40 modern constellations tofill gaps.

20. Constellations • In 1928, the International Astronomical Union established 88 official constellations with clearly defined boundaries. • Thus, a constellation now represents not a group of stars, but an area of the sky. Any starwithin the region belongs to one, and onlyone, constellation.

21. In addition to the 88 official constellations, the sky contains a number of less formally defined groupings called asterisms. The Big Dipper, for example, is a well-known asterism that is part of the constellation Ursa Major (Great Bear). Another asterism is the Great Square of Pegasus, which includes three stars from Pegasus and one (Alpheratz) from Andromeda. Constellations

22. Constellations • Although constellations and asterisms are named based on what is visible in the sky, it is important to remember that most of these groupsare made up of starsthat are not physicallyassociated with oneanother.

23. Constellations • Some stars may be many times further away than others and moving through space in different directions. • The only thing they have in common is that they lie inapproximately the same direction from Earth.

24. The Names of the Stars • In addition to naming groups of stars, ancient astronomers named the brighter stars. Modern astronomers still use many of those names.

25. Whereas the names of the constellations are in Latin, the common language of science in Renaissance Europe, most star names derive from ancient Arabic. Although, they have been much altered by the passing of centuries. The Names of the Stars

26. The Names of the Stars • The name of Betelgeuse, the bright red star in Orion, for example, comes from the Arabic yad al-jawza, meaning ‘armpit of Jawza (Orion).’ • Aldebaran, the bright red eye of Taurus the bull, comes from the Arabic al-dabar-an, meaning ‘the follower.’

27. The Names of the Stars • Naming individual stars is not very helpful, because you can see thousands of them and the names do not help you locate stars in the sky.

28. The Names of the Stars • Another way to identify stars is to assign Greek letters to the bright stars in a constellation in the approximate order of brightness. • Thus, the brightest star is usually designated α (alpha), the secondbrightest β (beta),and so on.

29. In many constellations, the letters follow the order of brightness. However, in some constellations, by tradition, mistake, or the personal preferences of early chartmakers, there are exceptions. The Names of the Stars

30. A star’s Greek-letter designation is the Greek letter followed by the genitive (possessive) form of the constellation name. For example, the brightest star in the constellation Canis Major is α Canis Majoris. This identifies both the star and the constellation and gives a clue to the relative brightness of the star. Compare this with the ancient name for this star, Sirius, which tells you nothing about location or brightness. The Names of the Stars

31. The Names of the Stars • This method of identifying a star’s brightness is only approximate. • In order to discuss the sky with precision, you must have an accurate way of referring to the brightness of stars. • For that, you must consult Hipparchus, one of the first great astronomers.

32. Astronomers measure the brightness of stars using the magnitude scale, a system that first appeared in the writings of the ancient astronomer Claudius Ptolemy about 140 AD. The system may have originated earlier than Ptolemy, and most astronomers attribute it to the Greek astronomer Hipparchus (160-127 BC). The Brightness of Stars

33. The ancient astronomers divided the stars into six classes. The brightest were called first-magnitude stars and those that were fainter, second-magnitude. The scale continued downward to sixth-magnitude stars, the faintest visible to the human eye. Thus, the larger the magnitude number, the fainter the star. This makes sense if you think of the bright stars as first-class stars and the faintest stars visible as sixth-class stars. The Brightness of Stars

34. Hipparchus is believed to have compiled the first star catalog, and he may have used the magnitude system in that catalog. Almost 300 years later, Ptolemy used the magnitude system in his own catalog, and successive generations of astronomers have continued to use the system. The Brightness of Stars

35. Modern astronomers can measure the brightness of starsto high precision. So, instead of saying that the star known by the charming name Chort (Theta Leonis)is third magnitude, they can say itsmagnitude is 3.34. The Brightness of Stars

36. The Brightness of Stars • If you measure magnitudes, you will discover that some stars are brighter than 1.0. For example, Vega (α Lyrae) is so bright that its magnitude, 0.04, is almost zero. • A few are so bright that the magnitude scale must extend into negative numbers. On this scale Sirius, the brighteststar in thesky, has amagnitudeof -1.47.

37. The Brightness of Stars • If you use a telescope to search for very faint stars, you can find stars much fainter than the limit for the unaided eye. • Thus, the magnitude system has also been extended to numbers larger than sixth magnitude to include fainter stars.

38. These numbers are known as apparent visual magnitudes (mv), and they describe how the stars look to human eyes observing from Earth. Although some stars emit large amounts of infrared or ultraviolet light, humans can’t see it. It is not included in the apparent visual magnitude. The subscript ‘v’ reminds you that you are including only light you can see. The Brightness of Stars

39. The Brightness of Stars • Another problem is distance. • Very distant stars look fainter and nearby stars look brighter. • Apparent visual magnitude ignores the effect of distance and tells only how bright the star looks, as seen from Earth.

40. Sometimes, it is convenient for astronomers to convert apparent visual magnitude into intensity—a measure of the light energy from a star that hits one square meter in one second. The Brightness of Stars

41. A simple relationship connects apparent visual magnitudes and the intensity of starlight. Thus, modern astronomers can measure the brightness of stars to high precision, while still making comparisons to observations of apparent visual magnitude that go back to the time of Hipparchus. The Brightness of Stars

42. Building Scientific Arguments • Nonastronomers sometimes complain that the magnitude scale is awkward. • Why would they think it is awkward, and how did it get that way?

43. Two things might make the magnitude scale seem awkward. First, it seems backward: the bigger the magnitude number, the fainter the star. Of course, that is because ancient astronomers were not measuring the brightness of stars but rather classifying them, and first-class stars would be brighter than second-class stars. Building Scientific Arguments

44. The second awkward feature of the magnitude scale is its mathematical relation to intensity. If two stars differ by one magnitude, one is about 2.5 times brighter than the other. But, if they differ by two magnitudes, one is 2.5 x 2.5 times brighter. This mathematical relationship arises because of the way human eyes perceive brightness as ratios of intensity. Building Scientific Arguments

45. Now, build your own scientific argument to analyze the following question. If the magnitude scale is so awkward, why do you suppose astronomers have used it for over two millennia? Building Scientific Arguments

46. The Sky and Its Motion • Ancient astronomers believed the sky was a great sphere surrounding Earth, with the stars stuck on the inside likethumbtacks in a ceiling. • Modern astronomers know thatthe stars are scattered throughspace at different distances, butit is still convenient to think ofthe sky as a great starry sphereenclosing Earth.

47. As you study the sky, you will notice three important points. One, the sky appears to rotate westward around Earth each day, but that is a consequence of the eastward rotation of Earth. That rotation produces day and night. Two, astronomers measure distances across the sky as angles and express them as degrees, minutes, and seconds. The Celestial Sphere

48. Three, what you can see of the sky depends on where you are on Earth. If you lived in Australia, you would see many constellations and asterisms invisible from North America. For example, the star Alpha Centauri is in the southern sky and isn’t visible from most of the United States. You could just glimpse it above the southern horizon if you were in Miami, but you could see it easily from Australia. The Celestial Sphere

49. The Celestial Sphere • The celestial sphere is an example of a scientific model, a common feature of scientific thought. • Notice that a scientific model does not have to be true to be useful.

50. In addition to the daily motion of the sky, Earth’s rotation adds a second motion to the sky that can be detected only over centuries. Over 2,000 years ago, Hipparchus compared a few of his star positions with those recorded nearly two centuries before and realized that the celestial poles and equator were slowly moving across the sky. Later astronomers understood that this motion is caused by the top-like motion of Earth. Precession