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Transcript
Our Universe 1 Universe TEKS (8.13) Science concepts. The student knows characteristics of the universe. The student is expected to: (8.13A) describe characteristics of the universe such as stars and galaxies. (8.13B) explain the use of light years to describe distances in the universe. (8.13C) research and describe historical scientific theories of the origin of the 2 Universe TAKS Objectives Objective 5: The student will demonstrate an understanding of earth and space systems. Components in the universe may also be included, such as stars, nebulae, and comets. Characteristics of the universe such as stars and galaxies may be integrated with all grade 8 objectives to make them more 3 relevant. Once Upon a Time….. 12- 15 Billion Years ago all the contents of the Universe were gathered into a small area under extreme heat and pressure. THEN 4 The Big Bang The Big Bang Theory is one theory of the formation of the Universe. It states that the universe began with a tremendous explosion http://hrw.com 5 Evidence to Support the Big Bang Theory 1. The even Spread of Radiation Thermal energy from the original explosion was distributed in every direction. 6 Even Spread of Background Radiation 7 Evidence to Support the Big Bang Theory 2. The Red Shift of Galaxies The spectrum of the distant galaxies is shifted to the red end. 8 Red Shift Of a Galaxies Spectrum Galaxies moving away from us would have their light waves stretched out and the spectrum would shift to the red end. Galaxies moving toward us would have their light waves compressed and the spectrum would shift to the blue end. All distant Galaxies have a red shift. 9 Doppler Effect Just like light waves, sound waves will also be compressed as an object moves toward you and they will be stretched as the object moves away. 10 Universe contains: 1. 2. 3. 4. 5. Galaxies Stars Nebulae Quasars Comets 11 Galaxies There are three main types of Galaxies –Spiral –Elliptical –Irregular 12 Spiral Galaxies – Characterized by a bulge at the center and spiral arms – Spiral shape is caused by the rotation of the galaxy http://hrw.com 13 Elliptical Galaxies – Characterized by a very bright centers and very little dust and gas – Appear elongated or spherical and are basically massive blobs of stars – Composed of mostly old stars http://hrw.com 14 Irregular Galaxies – Galaxies that do not fit into any other class – As their name indicates they have irregular shapes http://hrw.com 15 Stars Composition Brightness Temperature Mass Life Cycle 16 Stars Composition –Made up of different elements in the form of gasses –When viewed through a spectrograph the specific gasses can be identified through an absorption spectrum which is a continuous spectrum with dark lines where less light gets through. 17 Stars Composition http://hrw.com 18 Stars Brightness –Apparent Magnitude – how bright a star looks from Earth –Absolute Magnitude – how bright a star actually is (How bright the star would appear to the human eye if it were at a distance of 10 parsecs from the earth) 19 Stars Temperature Determined by the color of a star Classified by the following letter categories (O, B, A, F, G, K, M) http://hrw.com 20 Stars http://hrw.com The Hertzsprung Russell Diagram (H-R) is a graph showing the relationship between a star’s surface temperature and its absolute magnitude 21 Stars Illustrating the relationship between temperature and brightness http://hrw.com 22 Stars Mass Single most important determiner of a stars life cycle High Mass Low Mass http://www.enchantedlearning.com/subjects/astronomy/stars/lifecycle 23 Stars Illustrating the relationship between mass and star life time http://hrw.com 24 Stars Illustrating the relationship between mass and brightness http://hrw.com 25 Nebula Latin for “Cloud” Giant clouds of gas and dust Where new stars are formed Found in spiral galaxies Not found in elliptical galaxies http://nssdc.gsfc.nasa.gov/photo_gallery/photogallery-astro-nebula.html 26 Quasars The most powerful energy source in the universe May be the core of young galaxies forming Among the most distant objects in space from Earth http://hubblesite.org/newscenter/newsdesk/archive/releases/category/galaxy/quasar_active%20nucleus/ 27 Comets A comet is made of dirty ice, dust, and gas. When a comet gets close to the Sun, part of the ice starts to melt. This lets the dust and gas out. Solar winds then push them away from the comet. This makes the comet's tail. Every time a comet comes close to the Sun, a part of it melts. Over time, it will completely disappear. A comet does not give off any light of its own. Ice in the comet acts just like a mirror. What we see is sunlight bouncing off the comet. http://www.nasa.gov/audience/forkids/home/F_SC_comet.html 28 Comets Halebopp Comet 29 http://www.nashttp://deepimpact.jpl.nasa.gov/science/comets.html Looking through the center of the Milky Way 30 http://www.nashttp://deepimpact.jpl.nasa.gov/science/comets.html Questions and Discussion 1. Which characteristics are used to classify stars? A. temperature B. brightness (magnitude) C. mass D. All of the above 31 Questions and Discussion 1. Which characteristics are used to classify stars? A. temperature B. brightness (magnitude) C. mass D. All of the above 32 Questions and Discussion 1. Temperature and brightness are both used to classify stars as seen on the HR diagram, but mass is also important because it determines a stars temperature and brightness. http://hrw.com 33 Questions and Discussion 2. If a star becomes a black hole at the end of its life, it is a? A. high mass star B. nebula C. low mass star D. All of the above 34 Questions and Discussion 2. If a star becomes a black hole at the end of its life, it is a? A. high mass star B. nebula C. low mass star D. All of the above 35 Questions and Discussion 2. Becoming a black hole would mean that the star was a high mass star, giant actually as seen in the following illustration. http://www.enchantedlearning.com/subjects/astronomy/stars/lifecycle 36 Questions and Discussion 3. Galaxies are classified based on their? A. composition B. color C. shape D. All of the above 37 Questions and Discussion 3. Galaxies are classified based on their? A. composition B. color C. shape D. All of the above 38 Questions and Discussion 3. Galaxies are classified based on their shape. This is evident because of their name categories. The categories of galaxies are spiral, elliptical and irregular. http://hrw.com 39 Questions and Discussion 4. Scientist believe that quasars give off as much light as 10 trillion suns because of their? A. composition B. distance and brightness C. shape D. color 40 Questions and Discussion 4. Scientist believe that quasars give off as much light as 10 trillion suns because of their? A. name B. distance and brightness C. shape D. color 41 Questions and Discussion 4. Scientist know the absolute brightness of a quasar known as PKS 0637-152, and they know that it gives off as much light as 10 trillion suns because of its calculated distance using parallax. http://hrw.com 42