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Prepare your scantron: Fill in your name and fill the bubbles under your name. LAST NAME FIRST, First name second Put your 4-digit code instead of “ IDENTIFICATION NUMBER ”. --- (The last 4 digits of your OleMiss ID.) Question # 1: answer A Question # 2: answer A Question # 3: answer B Setup: Please take a moment to mute your cell phone! Use a pencil, not a pen! Reading assignment Chapter 2, pp. 24-52 (Discover the Universe – for background reading) Start of next class: review questions! Students with miss classes will be dropped tomorrow. Watch your email!!
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sec 45 Question 4 403530252019181716151413121110 9 8 7 6 5 4 3 2 1 0 Next question coming … Was Earth born before, after, or same time as the Sun? A Earth was born half time between the formation of the Sun and the present. B Earth was born a short time before the Sun did. C Earth was born soon after of the Sun was. D Earth was born much more recently than the Sun was. E Earth was born long before the Sun and was captured by the Sun’s gravity. This question counts double!
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sec 30 Question 5 29 The Sun is in the center of … A The Solar System, which is the same thing a the Galaxy. B The Solar System. C The Galaxy. D The Galaxy and the Solar System. E The Universe. 282726252423222120 19 181716151413121110 9 8 7 6 5 4 3 2 1 0 Next question coming … Question not graded.
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sec 30 Question 6 29282726252423222120 19 181716151413121110 9 8 7 6 5 4 3 2 1 0 Question not graded.
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sec 45 Question 7 403530252019181716151413121110 9 8 7 6 5 4 3 2 1 0 What is a light year? A A long time. Stars live a lot longer than one light year. B A distance. The closest star is 1 AU from the Sun, which is much closer than a light year. C A time as long as the lifetime of a star. D A distance. The diameter of the Galaxy is about one light year. E A distance. The closest star is 4 light years from us. This question counts double!
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Constellations and designations of stars Constellation = random collection of stars (figure) Stars ’ names: Greek letter + constellation name Orionis (= Betelgeuse) Orionis ( No special name) Canis Majoris (= Sirius)
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More star names Find: Leporis Geminorum Tauri A few distances: Canis Maioris - 9 ly Canis Maioris - 500 ly Canis Maioris - 1,800 ly Canis Maioris - 430 ly 95% of the 6,000 naked-eye stars are at 50 to 500 ly: in the solar neighborhood. Inside Taurus!
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Questions coming …
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sec 45 Question 8 403530252019181716151413121110 9 8 7 6 5 4 3 2 1 0 Next question coming … Which constellation is closer to us, and how do we know? A The Big Dipper is closer than Orion because the Big Dipper looks larger in the sky. B Orion is closer than the Big Dipper because Orion ’ s stars look brighter in the sky. C All constellations are at the same distance. D This question is nonsense because constellations are not real objects. E This question is nonsense because the distance to constellations changes as Earth revolves around the Sun.
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sec 30 Question 9 29 What is Canis Maioris? A The name of a bright star. B The name of a planet. C The name of a constellation. D A galaxy. E The name of a moon revolving around the planet Canis Maioris. 282726252423222120 19 181716151413121110 9 8 7 6 5 4 3 2 1 0 Next question coming …
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sec 30 Question 10 29 The Pleiades (the “ Seven Sisters ” ) is … A A constellation. B A star. C Not a constellation, but it is a star cluster inside the constellation of Taurus. D A constellation, which is the same thing as a star cluster. E A collection of seven random stars, unrelated to each other. 282726252423222120 19 181716151413121110 9 8 7 6 5 4 3 2 1 0 Next question coming …
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sec 45 Question 11 403530252019181716151413121110 9 8 7 6 5 4 3 2 1 0 Most of the stars visible in the sky by the naked eye are … A outside the Galaxy. B inside the Galaxy, but not necessarily in the vicinity of the Sun. C inside the Galaxy, and mostly in the vicinity of the Sun. D 50% inside the Galaxy, 50% outside. E nowhere close to the Galaxy, which is much farther away from us than the individual stars in the sky are.
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Brightness of stars Understand brightness of stars: the magnitude scale A first magnitude star: m = 1 mg A second magnitude star: m = 2 mg A third magnitude star: m = 3 mg A fifth magnitude star: m = 5 mg,, just visible to the naked eye The Andromeda Galaxy m = 3 mg in total An m = 10 mg, star, need an amateur telescope to see it An m = 17 mg, star, need a professional telescope to see it Magnitudes mean brightness: The larger the number, the fainter the object One magnitude difference means a lot dimmer (2.5 times) m = 2.5 × lg I __ Vega I
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Example: stars in the Big Dipper 1.9 mg 2.2 mg 4.0 mg 3.3 mg 5.6 mg
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Questions coming …
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sec 30 Question 12 29 The magnitude of a star tells us … A How far the star us from us. B How bright the star appears in the sky. C How bright the star is in reality. D How large the star appears in the sky. E How large the star is in reality. 282726252423222120 19 181716151413121110 9 8 7 6 5 4 3 2 1 0 Next question coming …
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sec 30 Question 13 29 Which one is brighter, a 1 mg star or a 5 mg star, and how much? A The magnitude of a star does not refer to brightness at all, it refers to size. B The 1 mg star is much brighter. C The 1 mg star is a little brighter. D The 1 mg star is much fainter. E The 1 mg star is a little fainter. 282726252423222120 19 181716151413121110 9 8 7 6 5 4 3 2 1 0 Next question coming …
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sec 30 Question 14 29 Do you need a telescope to see Pluto whose brightness is a 15 mg ? A No, it can be seen by the naked eye. B Yes, but even binoculars will suffice. C Yes, a small amateur telescope is needed. D A fairly large amateur telescope or a small professional telescope is needed. E Pluto is only observable in the largest professional telescopes in the world. 282726252423222120 19 181716151413121110 9 8 7 6 5 4 3 2 1 0
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How bright do you think Orionis is? Exercises on magnitudes 1 How bright do you think Orionis is? This is how Orion looks to a naked-eye observer in complete darkness. Orionis : 2.0 mg Orionis : 4.3 mg Orionis is one of the brightest stars in the sky. How bright do you think it is? Orionis: 0.5 mg
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Exercises on magnitudes 2 Capella is 0 mg. How bright do you think the following are? Pleiades2 mg Aldebaran1 mg Jupiter- 2 mg Venus- 4 mg International Space Station 1 mg
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