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Unit 1 The Universe Mrs. Williams 8th Grade Big Idea: The sun is one of billions of stars in one of billions of galaxies in the universe.

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Presentation on theme: "Unit 1 The Universe Mrs. Williams 8th Grade Big Idea: The sun is one of billions of stars in one of billions of galaxies in the universe."— Presentation transcript:

1 Unit 1 The Universe Mrs. Williams 8th Grade Big Idea: The sun is one of billions of stars in one of billions of galaxies in the universe.

2 Big Idea:

3 Our Place in Space Universe-space & all the matter & energy in it. Galaxy- a large collection of stars, gas, & dust There are an estimated 100 billion galaxies in the universe. Unit 1 Lesson 1 Structure of the Universe

4 Types of Galaxies Spiral galaxies are shaped like pinwheels. They have a central bulge from which two or more spiral arms extend. Elliptical galaxies look like spheres or ovals and do not have spiral arms. Irregular galaxies appear as splotchy, irregularly shaped “blobs.” They are very active areas of star formation. Unit 1 Lesson 1 Structure of the Universe

5 What Makes Up the Universe? Solar system- the collection of large & small bodies that orbit our central star, the sun. Planet-spherical body that orbits the sun. Unit 1 Lesson 1 Structure of the Universe

6 Terrestrial Planets Terrestrial Planets- rocky, dense, and relatively small. Mercury, Venus, Earth and Mars Unit 1 Lesson 1 Structure of the Universe

7 Gas giant planets - have thick, gaseous atmospheres; small, rocky cores; and ring systems of ice, rock, and dust. Jupiter, Saturn, Uranus, and Neptune. Unit 1 Lesson 1 Structure of the Universe

8 Small Bodies in the Universe Moons- orbit most of the planets. Earth has only one moon, but Jupiter has more than 60. The solar system has other small bodies, including Dwarf planets Comets Asteroids Meteoroids Unit 1 Lesson 1 Structure of the Universe

9 Measuring the Universe Distances between most objects in the universe are so large that astronomers measure distances using the speed of light. Light-year -the distance that light travels through space in one year. Light travels through space at about 300,000 km/s, or about 9.5 trillion kilometers in one year. Unit 1 Lesson 1 Structure of the Universe

10 Reach For The Stars! Star - large celestial body that is composed of gas & emits light. Most stars are composed almost entirely of hydrogen and helium. Stars emit light and vary in brightness, size and temperatures. Unit 1 Lesson 1 Structure of the Universe

11 You’re a Shining Star How is star brightness measured? Apparent magnitude -measure of a star’s brightness as seen from Earth. – Luminosity- actual brightness of a star. Absolute magnitude -measure of how bright a star would be if the star were located at a standard distance. Unit 1 Lesson 2 Stars

12 Too HOT to Handle Surface temperatures of Stars are measured by their COLOR COLORSURFACE TEMPERATURE (˚C) BlueAbove 25,000 Blue-white10,000-25,000 White7,500-10,000 Yellow-white6,000-7,500 Yellow5,000-6,000 Orange3,500-5,000 RedBelow 3,500 Unit 1 Lesson 2 Stars

13 Stars differ greatly in size White dwarfs - Very small stars have about the same radius as Earth, which is approximately 0.01 solar radius. Giant stars - Very large stars, typically have sizes between 10 and 100 times the sun’s radius. Supergiants - Some rare, extremely large stars have sizes of up to 1,000 solar radii. Unit 1 Lesson 2 Stars

14 A Star Is Born What is the life cycle of a star? Stars form in nebulae. Nebula -large cloud of gas and dust. It is composed mainly of hydrogen and helium, with small amounts of heavier elements. Unit 1 Lesson 3 The Life Cycle of Stars

15 Birth of a Star Nuclear fusion – high temp & pressure cause two or more low-mass atomic nuclei to form a heavier nucleus. Gives off light. Occurs for most of the stars life. Unit 1 Lesson 3 The Life Cycle of Stars

16 The Lightweights Low-mass stars- The sun is a low mass, medium size star. – Giants-large red stars due to star’s outer atmosphere expanding after active fusion ends. – White dwarf -hot, dense core of matter that remains from the collapse of a low- mass star. It is about the size of Earth. Unit 1 Lesson 3 The Life Cycle of Stars

17 The Heavyweights High mass stars – Supergiant-produces heavier elements like carbon – Supernova -gigantic explosion in which a high-mass star collapses, throwing its outer layers into space. But its core remains. – Neutron star -small, incredibly dense ball of closely packed neutrons. – Black hole -invisible object with gravity so great that nothing, not even light, can escape it. Unit 1 Lesson 3 The Life Cycle of Stars

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19 A Graphic Display H-R diagram –graph that shows the relationship between the stars surface temperature & absolute magnitude ( brightness/luminosity ) Main sequence -region of the diagram where stars spend most of their lives. (actively fusing hydrogen) Unit 1 Lesson 3 The Life Cycle of Stars


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