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Slide 2 Chapter Menu Chapter Introduction Lesson 1Lesson 1The View from Earth Lesson 2Lesson 2The Sun and Other Stars Lesson 3Lesson 3Evolution of Stars Lesson 4Lesson 4Galaxies and the Universe Chapter Wrap-Up Slide 3 Chapter Introduction What makes up the universe and how does gravity affect the universe? Slide 4 Chapter Introduction What do you think? Before you begin, decide if you agree or disagree with each of these statements. As you view this presentation, see if you change your mind about any of the statements. Slide 5 Chapter Introduction 1.The night sky is divided into constellations. 2.A light-year is a measurement of time. 3.Stars shine because there are nuclear reactions in their cores. 4.Sunspots appear dark because they are cooler than nearby areas. Do you agree or disagree? Slide 6 Chapter Introduction 5.The more matter a star contains, the longer it is able to shine. 6.Gravity plays an important role in the formation of stars. 7.Most of the mass in the universe is in stars. 8.The Big Bang theory is an explanation of the beginning of the universe. Do you agree or disagree? Slide 7 Lesson 1 Reading Guide - KC How do astronomers divide the night sky? What can astronomers learn about stars from their light? How do scientists measure the distance and the brightness of objects in the sky? The View from Earth Slide 8 Lesson 1 Reading Guide - Vocab spectroscope astronomical unit light-year apparent magnitude luminosity The View from Earth Slide 9 Lesson 1-1 The star Polaris is almost directly above the North Pole. Earths rotation causes other stars to appear to revolve around Polaris. Looking at the Night Sky CORBIS Slide 10 Lesson 1-1 Present-day astronomers use many ancient constellations to divide the sky into 88 regions. Slide 11 Lesson 1-1 Dividing the sky helps scientists communicate to others what area of sky they are studying. Slide 12 Lesson 1-1 Looking at the Night Sky (cont.) How do astronomers divide the night sky? Slide 13 Lesson 1-1 Telescopes can collect more light than the human eye can. Looking at the Night Sky (cont.) Michael Matisse/Getty Images Steve Allen/Brand X Pictures Slide 14 Lesson 1-1 The electromagnetic spectrum is a continuous range of wavelengths. Looking at the Night Sky (cont.) Slide 15 Lesson 1-1 Different parts of the electromagnetic spectrum have different wavelengths and different energies. You can see only a small part of the energy in these wavelengths. Slide 16 Lesson 1-1 The set of wavelengths that a star emits is the stars spectrum. A spectroscope spreads light into different wavelengths.spectroscope Using spectroscopes, astronomers can study stars characteristics, including temperatures, compositions, and energies. Looking at the Night Sky (cont.) Slide 17 Lesson 1-1 Looking at the Night Sky (cont.) What can astronomers learn from a stars spectrum? Slide 18 Lesson 1-2 Parallax is the apparent change in an objects position caused by looking at it from two different points. Measuring Distances parallax from Greek parallaxis, means alteration Slide 19 Lesson 1-2 Astronomers use parallax to calculate how far an object in space is from Earth. The object is viewed from two extreme points in Earths orbit. Slide 20 Lesson 1-2 An astronomical unit is the average distance between Earth and the Sun, about 150 million km.astronomical unit Slide 21 Lesson 1-2 A light-year is the distance light travels in 1 year.light-year One light-year is about 10 trillion km. Measuring Distances (cont.) Slide 22 Lesson 1-3 The apparent magnitude of an object is a measure of how bright it appears from Earth.apparent magnitude Measuring Brightness Slide 23 Lesson 1-3 Luminosity is the true brightness of an object.Luminosity The luminosity of a star, measured on an absolute magnitude scale, depends on the stars temperature and size, not its distance from Earth. Measuring Brightness (cont.) Slide 24 Lesson 1-3 Measuring Brightness (cont.) How do scientists measure the brightness of stars? Slide 25 Lesson 1 - VS Astronomers use ancient constellations to divide the sky into sections, also called constellations. Slide 26 Lesson 1 - VS Different wavelengths of the electromagnetic spectrum carry different energies. Slide 27 Lesson 1 - VS Astronomers measure distances within the solar system using astronomical units. Slide 28 Lesson 1 LR1 A.luminosity B.light-year C.apparent magnitude D.absolute magnitude Which term refers to how bright an object appears from Earth? Slide 29 Lesson 1 LR2 A.one million B.ten million C.one trillion D.ten trillion One light-year is equal to about how many kilometers? Slide 30 Lesson 1 LR3 A.brightness B.luminosity C.magnitude D.spectrum Which term refers to the range of wavelengths a star emits? Slide 31 Lesson 1 - Now 1.The night sky is divided into constellations. 2.A light-year is a measurement of time. Do you agree or disagree? Slide 32 Lesson 2 Reading Guide - KC How do stars shine? How are stars layered? How does the Sun change over short periods of time? How do scientists classify stars? The Sun and Other Stars Slide 33 Lesson 2 Reading Guide - Vocab nuclear fusion star radiative zone convection zoneconvection zone The Sun and Other Stars photosphere chromosphere corona Hertzsprung- Russell diagramHertzsprung- Russell diagram Slide 34 Lesson 2-1 How Stars Shine A star is a large ball of gas held together by gravity with a core so hot that nuclear fusion occurs.star Nuclear fusion occurs when the nuclei of several atoms combine into one larger nucleus.Nuclear fusion Slide 35 Lesson 2-1 How Stars Shine (cont.) Nuclear fusion releases a large amount of energy. A star shines because when energy leaves a stars core, it travels throughout the star and radiates into space. Slide 36 Lesson 2-1 How Stars Shine (cont.) How do stars shine? Slide 37 Lesson 2-2 Spectra of the Sun and other stars provide information about stellar composition. Composition and Structure of Stars stellar Science Use anything related to stars Common Use outstanding, exemplary Slide 38 Lesson 2-2 There are three interior layers of a typical star. When first formed, all stars fuse hydrogen into helium in their cores. Composition and Structure of Stars (cont.) Slide 39 Lesson 2-2 The radiative zone is a shell of cooler hydrogen around a stars core.radiative zone In the convection zone, hot gases move toward the surface as cooler gases move down into the interior.convection zone Composition and Structure of Stars (cont.) Slide 40 Lesson 2-2 Composition and Structure of Stars (cont.) What are the interior layers of a star? Slide 41 Lesson 2-2 Beyond the convection zone are the three layers of a stars atmosphere the photosphere, the chromosphere, and the corona. Composition and Structure of Stars (cont.) Slide 42 Lesson 2-2 The photosphere is the apparent surface of a star, where light energy radiates into space.photosphere Composition and Structure of Stars (cont.) Slide 43 Lesson 2-2 The chromosphere is the orange-red layer above the photosphere.chromosphere The corona is the wide, outermost layer of a stars atmosphere.corona Composition and Structure of Stars (cont.) Slide 44 Lesson 2-2 Changing Features of the Sun: Sunspots Cooler regions of magnetic activity Seem to move as the Sun rotates Number varies on an 11-year cycle Digital Vision/PunchStock Slide 45 Lesson 2-2 Changing Features of the Sun: Coronal Mass Ejections (CMEs) Huge gas bubbles ejected from the corona Larger than flares May reach Earth Can cause radio blackouts NASA Slide 46 Lesson 2-2 Changing Features of the Sun: Prominences and Flares Prominences clouds and jets of gases forming loops into the corona Flaressudden increases in brightness, often near sunspots or prominences SOHO Consortium, ESA, NASA Slide 47 Lesson 2-2 Changing Features of the Sun: The Solar Wind Caused by charged particles streaming away from the Sun Extends to the edge of the solar system Causes auroras CORBIS Slide 48 Lesson 2-3 Most stars exist in star systems bound by gravity. Many stars exist in large groupings called clusters. Stars in a cluster all formed at about the same time and are the same distance from Earth. Groups of Stars Slide 49 Lesson 2-4 Scientists classify stars according to their spectra. Though there are exceptions, color in most stars is related to mass. Classifying Stars Slide 50 Lesson 2-4 Blue-white stars tend to have the most mass, followed by white stars, yellow stars, orange stars, and red stars. Slide 51 Lesson 2-4 The Hertzsprung-Russell diagram is a graph that plots luminosity against temperature of stars.Hertzsprung-Russell diagram Slide 52 Lesson 2-4 The y-axis of the H-R diagram displays increasing luminosity and the x-axis displays decreasing temperature. Slide 53 Lesson 2-4 Most stars exist along the main sequence. Slide 54 Lesson 2-4 The mass of a main-sequence star determines both its temperature and its luminosity Slide 55 Lesson 2-4 Classifying Stars (cont.) What is the Hertzsprung- Russell diagram? Slide 56 Lesson 2 - VS Hot gas moves up and cool gas moves down in the Suns convection zone. Slide 57 Lesson 2 - VS Sunspots are relatively dark areas on the Sun that have strong magnetic activity. Globular clusters contain hundreds of thousands of stars. Slide 58 Lesson 2 LR1 A.radiative zone B.corona C.convection zone D.chromosphere Which term refers to the wide, outermost layer of a stars atmosphere? Slide 59 Lesson 2 LR2 A.mass B.size C.spectra D.temperature Scientists classify stars according to which of these? Slide 60 Lesson 2 LR3 A.yellow B.red C.orange D.blue-white What color of stars tend to have the most mass? Slide 61 Lesson 2 - Now 3.Stars shine because there are nuclear reactions in their cores. 4.Sunspots appear dark because they are cooler than nearby areas. Do you agree or disagree? Slide 62 Lesson 3 Reading Guide - KC How do stars form? How does a stars mass affect its evolution? How is star matter recycled in space? Evolution of Stars Slide 63 Lesson 3 Reading Guide - Vocab nebula white dwarf supernova neutron star black hole Evolution of Stars Slide 64 Lesson 3-1 Stars form deep inside clouds of gas and dust. A cloud of gas and dust is a nebula.nebula Life Cycle of a Star nebula from Latin nebula, means mist or little cloud Slide 65 Lesson 3-1 Star-forming nebulae are cold, dense, and dark. Life Cycle of a Star (cont.) Photo courtesy of NASA/Corbis Slide 66 Lesson 3-1 Gravity causes the densest parts to collapse, forming regions called protostars. Over many thousands of years, the energy produced by protostars heats the gas and dust surrounding them. Life Cycle of a Star (cont.) Slide 67 Lesson 3-1 Life Cycle of a Star (cont.) How do stars form? Slide 68 Lesson 3-1 A star becomes a main-sequence star as soon as it begins to fuse hydrogen into helium. Low-mass stars stay on the main sequence for billions of years, and high-mass stars are there for only a few million years. Life Cycle of a Star (cont.) Slide 69 Lesson 3-1 When a stars hydrogen supply is nearly gone, the star leaves the main sequence and begins the next stage of its life cycle. All stars form in the same way, but stars die in different ways, depending on their masses. Massive stars eventually become red supergiants. Life Cycle of a Star (cont.) Slide 70 Lesson 3-1 Slide 71 Lesson 3-2 After helium in the cores of lower-mass stars is gone, the stars cast off their gases, exposing their cores. The core eventually becomes a white dwarf, a hot, dense, slowly cooling sphere of carbon.white dwarf This is what is expected to happen to the Sun. End of a Star Slide 72 Lesson 3-2 The Sun will remain on the main sequence for 5 billion more years. Slide 73 Lesson 3-2 When the Sun becomes a red giant for the second time, it will probably absorb Earth and push Mars and Jupiter outward. Slide 74 Lesson 3-2 When the Sun becomes a white dwarf, the solar system will be a cold, dark place. Slide 75 Lesson 3-2 Very massive stars can explode in a supernova, which destroys the star. supernova Iron in the core does not fuse and the core collapses quickly under the force of gravity. The normal space within atoms is eliminated, leaving a dense core of neutrons, or a neutron star.neutron star End of a Star (cont.) Slide 76 Lesson 3-2 For the most massive stars, atomic forces holding neutrons together are not strong enough to overcome so much mass in such a small volume. Gravity is too strong, and the matter crushes into a black hole. A black hole is an object whose gravity is so great that no light can escape.black hole End of a Star (cont.) Slide 77 Lesson 3-2 End of a Star (cont.) How does a stars mass determine if it will become a white dwarf, a neutron star, or a black hole? Slide 78 Lesson 3-3 When a star becomes a white dwarf, it casts off hydrogen and helium gases in its outer layers. The expanding, cast-off matter of a white dwarf is a planetary nebula. During a supernova, a massive star comes apart sending a shock wave into space. Recycling Matter Slide 79 Lesson 3-3 The expanding cloud of dust and gas is called a supernova remnant. Gravity causes recycled gases and other matter to clump together in nebulae and form new stars and planets. Recycling Matter (cont.) Slide 80 Lesson 3-3 Recycling Matter (cont.) How do stars recycle matter? Slide 81 Lesson 3 - VS Iron is formed in the cores of the most massive stars. Slide 82 Lesson 3 - VS The Sun will become a red giant in about 5 billion years. Matter is recycled in supernovae. Slide 83 Lesson 3 LR1 A.white dwarf B.supernova C.nebula D.black hole What term refers to clouds of gas and dust where stars form? Slide 84 Lesson 3 LR2 A.neutron star B.red giant C.supernova D.white dwarf What type of star is a hot, dense, slowly cooling sphere of carbon? Slide 85 Lesson 3 LR3 A.white dwarf B.supernova C.nebula D.black hole Which of these is an object whose gravity is so great that no light can escape? Slide 86 Lesson 3 - Now 5.The more matter a star contains, the longer it is able to shine. 6.Gravity plays an important role in the formation of stars. Do you agree or disagree? Slide 87 Lesson 4 Reading Guide - KC What are the major types of galaxies? What is the Milky Way, and how is it related to the solar system? What is the Big Bang theory? Galaxies and the Universe Slide 88 Lesson 4 Reading Guide - Vocab galaxy dark matter Big Bang theory Doppler shift Galaxies and the Universe Slide 89 Lesson 4-1 Galaxies are huge collections of stars. Galaxies galaxy from Greek galactos, means milk Slide 90 Lesson 4-1 Gravity holds stars and galaxies together. When astronomers examine how galaxies rotate and gravitationally interact, they find that most of the matter in galaxies is invisible. Matter that emits no light at any wavelength is dark matter.dark matter Galaxies (cont.) Slide 91 Lesson 4-1 Types of Galaxies: Spiral Galaxies Spiral arms of stars, gas, and dust extend from central disk. Spiral galaxies have a central bulge. A spherical halo surrounds the disk. NASA/JPL-Caltech/S. Willner (Harvard-Smithsonian Center for Astrophysics) Slide 92 Lesson 4-1 Types of Galaxies: Elliptical Galaxies Elliptical galaxies have a spherical or elliptical shape and no internal structure. They contain more older stars than spiral galaxies, and may have formed as spiral galaxies merged. JPL/NASA Slide 93 Lesson 4-1 Types of Galaxies: Irregular Galaxies Irregular galaxies are oddly shaped and contain many young stars. Local Group Galaxies Survey Team, NOAO, AURA, NSF Slide 94 Lesson 4-1 Galaxies (cont.) What are the major types of galaxies? Slide 95 Lesson 4-2 The solar system is in the Milky Way, a spiral galaxy that contains gas, dust, and almost 200 billion stars. The Milky Way is a member of the Local Group, a cluster of about 30 galaxies. The Milky Way Slide 96 Lesson 4-2 Slide 97 The Milky Way (cont.) Where is Earth in the Milky Way? Slide 98 Lesson 4-3 According to the Big Bang theory, the universe began from one point billions of years ago and has been expanding ever since.Big Bang theory The Big Bang Theory What is the Big Bang theory? Slide 99 Lesson 4-3 Most scientists agree that the universe is 13-14 billion years old. Scientists observe how space stretches by measuring the speed at which galaxies move away from the Earth. The Big Bang Theory (cont.) Slide 100 Lesson 4-3 When light travels away from you, its wavelength stretches out, shifting to the red end of the electromagnetic spectrum. The shift to a different wavelength is called the Doppler shift.Doppler shift The Big Bang Theory (cont.) Slide 101 Lesson 4-3 Doppler Shift Slide 102 Lesson 4 - VS By studying interacting galaxies, scientists have determined that most mass in the universe is dark matter. The Sun is one of billions of stars in the Milky Way. Slide 103 Lesson 4 - VS When an object moves away, its light stretches out, just as a sirens sound waves stretch out as the siren moves away. Slide 104 Lesson 4 LR1 A.clusters B.dark matter C.H-R matter D.light matter What term refers to matter that emits no light at any wavelength? Slide 105 Lesson 4 LR2 A.5 B.30 C.200 D.1 billion The Milky Way is a member of the Local Group which is a cluster of about how many galaxies? Slide 106 Lesson 4 LR3 A.1-2 million years B.9-10 million years C.4-5 billion years D.13-14 billion years Approximately what is the age of the universe? Slide 107 Lesson 4 - Now 7.Most of the mass in the universe is in stars. 8.The Big Bang theory is an explanation of the beginning of the universe. Do you agree or disagree? Slide 108 Chapter Review Menu Key Concept Summary Interactive Concept Map Chapter Review Standardized Test Practice Slide 109 The BIG Idea The universe is made up of stars, gas, and dust, as well as invisible dark matter. Material in the universe is pulled by gravity into galaxies, including our own Milky Way galaxy. Slide 110 Key Concepts 1 The sky is divided into 88 constellations. Astronomers learn about the energy, distance, temperature, and composition of stars by studying their light. Astronomers measure distances in space in astrological units and in light-years. They measure star brightness as apparent magnitude and as luminosity. Lesson 1: The View from Earth Slide 111 Key Concepts 2 Lesson 2: The Sun and Other Stars Stars shine because of nuclear fusion in their cores. Stars have a layered structurethey conduct energy through their radiative zones and their convection zones and release the energy at their photospheres. Sunspots, prominences, flares, and coronal mass ejections are temporary phenomena on the Sun. Astronomers classify stars by their temperatures and luminosities. Slide 112 Key Concepts 3 Stars are born in clouds of gas and dust called nebulae. What happens to a star when it leaves the main sequence depends on its mass. Matter is recycled in the planetary nebulae of white dwarfs and the remnants of supernovae. Lesson 3: Evolution of Stars Slide 113 Key Concepts 4 The three major types of galaxies are spiral, elliptical, and irregular. The Milky Way is the spiral galaxy that contains the solar system. The Big Bang theory explains the origin of the universe. Lesson 4: Galaxies and the Universe Slide 114 Chapter Review MC1 A.astronomical unit B.Doppler shift C.light-year D.solar distance Which of these describes the average distance between Earth and the Sun? Slide 115 Chapter Review MC2 A.apparent magnitude B.astronomical unit C.luminosity D.spectrum The true brightness of an object can also be referred to as which of these? Slide 116 Chapter Review MC3 Which term refers to the apparent surface of a star? A.chromosphere B.convection zone C.corona D.photosphere Slide 117 Chapter Review MC4 A.supernova B.nebula C.Hertzsprung-Russell event D.Doppler shift Which is an enormous explosion that destroys a star? Slide 118 Chapter Review MC5 A.Big Bang theory B.Doppler shift C.H-R diagram D.law of magnitude The universe began from one point billions of years ago and has been expanding ever since, according to which of these? Slide 119 Chapter Review STP1 A.astronomical unit B.light-year C.solar magnitude D.2 trillion km Which of these refers to the distance light travels in one year? Slide 120 Chapter Review STP2 A.telescope B.spectroscope C.photosphere D.dark matter Which of these spreads light into different wavelengths? Slide 121 Chapter Review STP3 A.radiative zone B.photosphere C.corona D.convection zone Which of these is the shell of cooler hydrogen above a stars core? Slide 122 Chapter Review STP4 A.white dwarf B.neutron star C.nebula D.black hole Which of these is the dense core of matter left from a supernova? Slide 123 Chapter Review STP5 A.galaxies B.dark matter C.clusters D.astronomical units Which term refers to huge collections of stars?