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 (Discover the Universe – for background reading) Start of next class: review questions! Students with miss classes will be dropped tomorrow. Watch your !!

sec 45 Question 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!

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 Next question coming … Question not graded.

sec 30 Question Question not graded.

sec 45 Question 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!

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)

More star names Find:  Leporis  Geminorum  Tauri A few distances:  Canis Maioris - 9 ly  Canis Maioris ly  Canis Maioris - 1,800 ly  Canis Maioris ly 95% of the 6,000 naked-eye stars are at 50 to 500 ly: in the solar neighborhood. Inside Taurus!

Questions coming …

sec 45 Question 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.

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 Next question coming …

sec 30 Question 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 Next question coming …

sec 45 Question 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.

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

Example: stars in the Big Dipper 1.9 mg 2.2 mg 4.0 mg 3.3 mg 5.6 mg

Questions coming …

sec 30 Question 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 Next question coming …

sec 30 Question 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 Next question coming …

sec 30 Question 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

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

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