SPACE THE FINAL FRONTIER

1. SPACE THE FINAL FRONTIER

2. Look and Learn •Describe how color indicates the temperature of a star. •Explain how a scientist can identify a star’s composition. •Describe how scientists classify stars. •Compare absolute magnitude with apparent magnitude. •Identify how astronomers measure distances from Earth to stars. •Describe the difference between the apparent motion and the actual motion of stars.

4. Vocabulary • Spectrum the band of colors produced when white light passes through a prism • apparent magnitudethe brightness of a star as seen from Earth   • absolute magnitudethe brightness that a star would have at a distance of 32.6 light-years from Earth • light-yearthe distance that light travels in one year; about 9.46 trillion kilometers

5. PG 585 TEXTBOOK

6. North Star as 431 light-years than as 4,080,000,000,000,000 km.

7. VOCABULARY • Apparent Motion Stars appear to move across the sky due to the Earth's rotation. http://my.hrw.com/sh2/sh07_10/student/flash/visual_concepts/80354.htm • Absolute Motion

8. The color of a star depends on its temperature. Hot stars are blue. Cool stars are red. • The spectrum of a star shows the composition of a star. • Scientists classify stars by temperature and brightness. • Apparent magnitude is the brightness of a star as seen from Earth. Absolute magnitude is the measured brightness of a star at a distance of 32.6 light-years. • Astronomers use parallax and trigonometry to measure distances from Earth to stars. • Stars appear to move because of Earth’s rotation. However, the actual motion of stars is very hard to see because stars are so distant.

9. Types of Stars A star is a large celestial body that is composed of gas and that emits light. Stars are classified by how hot they are and are arranged in order of temperature. Temperature differences result in color differences that you can see. Pg 590 textbook

10.  - red gianta large, reddish star late in its life cycle    - white dwarfa small, hot, dim star that is the leftover center of an old star  - H-R diagram   - main sequence   - supernova   - neutron star   - pulsar   - black hole

11. A red giant large, reddish star late in its life cycle A white dwarf is what stars like the Sun become after they have exhausted their nuclear fuel.

12. When Stars Get Old Average stars, such as the sun, become red giants and then white dwarfs. Stars that are more massive than the sun may explode with such intensity that they become a variety of strange objects such as supernovas, neutron stars, pulsars, and black holes.

13. neutron stara star that has collapsed under gravity to the point that the electrons and protons have smashed together to form neutrons black holean object so massive and dense that even light cannot escape its gravity

14. Supernova a gigantic explosion in which a massive star collapses and throws its outer layers into space

15. Galaxy a collection of stars, dust, and gas bound together by gravity

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20. Section Summary • Edwin Hubble classified galaxies according to their shape including spiral, elliptical, and irregular galaxies. • Some galaxies consist of nebulas and star clusters. • Nebulas are large clouds of gas and dust. Globular clusters are tightly grouped stars. Open clusters are closely grouped stars. • Scientists look at distant galaxies to learn what early galaxies looked like.

21. cosmology. • the study of the origin, properties, processes, and evolution of the universe Describe the big bang theory. Explain evidence used to support the big bang theory. Describe the structure of the universe. Describe two ways scientists calculate the age of the universe. Explain what will happen if the universe expands forever

22. big bang theorythe theory that all matter and energy in the universe was compressed into an extremely small volume that 13 billion to 15 billion years ago exploded and began expanding in all directions

23. Every object in the universe is part of a larger system. Earth is part of our solar system, which is in turn part of the Milky Way galaxy. Pg 602

24. Observations show that the universe is expanding. • The big bang theory states that the universe began with an explosion about 13.7 billion years ago. • Cosmic background radiation helps support the big bang theory. • Scientists use different ways to calculate the age of the universe. • Scientists think that the universe may expand forever

26. stars

27. stars brightness

28. stars brightness Apparent magnitude

29. stars brightness Apparent magnitude Absolute magnitude

30. stars brightness temperature Apparent magnitude Absolute magnitude

31. stars brightness temperature Apparent magnitude Absolute magnitude

32. stars brightness temperature color Apparent magnitude Absolute magnitude

33. stars brightness composition temperature color Apparent magnitude Absolute magnitude

34. stars brightness composition temperature color Apparent magnitude Absolute magnitude spectra spectrograph

36. Holes Where Stars Once WereAn invisible phantom lurks in space, ready to swallow everything that comes near it. Once trapped in its grasp, matter is stretched, torn, and crushed into oblivion. Does this tale sound like a horror story? Guess again! Scientists call this phantom a black hole. As a star runs out of fuel, it cools and eventually collapses under the force of its own gravity. If the collapsing star is massive enough, it may shrink to become a black hole. The resulting gravitational attraction is so strong that even light cannot escape! Many astronomers think that black holes lie at the heart of many galaxies. Some scientists suggest that there is a giant black hole at the center of our own Milky Way.

37. The Orion Nebula, a vast cloud of dust and gas that is 35 trillion miles wide, is part of the familiar Orion constellation. Here, swirling clouds of dust and gas give birth to systems like our own solar system.

38. Explain the relationship between gravity and pressure in a nebula. •Describe how the solar system formed.

39. The Horsehead Nebula is a cold, dark cloud of gas and dust. But observations suggest that it is also a site where stars form.

40. Gravity Pulls Matter Together • The gas and dust that make up nebulas are made of matter. The matter of a nebula is held together by the force of gravity. In most nebulas, there is a lot of space between the particles. In fact, nebulas are less dense than air! Thus, the gravitational attraction between the particles in a nebula is very weak. The force is just enough to keep the nebula from drifting apart.

44. solar nebula • a rotating cloud of gas and dust from which the sun and planets formed

45. How the Solar System Formed

49. The solar system formed out of a vast cloud of gas and dust called the nebula. • Gravity and pressure were balanced until something upset the balance. Then, the nebula began to collapse. • Collapse of the solar nebula caused heating at the center, while planetesimals formed in surrounding space. • The central mass of the nebula became the sun. Planets formed from the surrounding materials.

50. Describe the basic structure and composition of the sun. •Explain how the sun generates energy. •Describe the surface activity of the sun, and identify how this activity affects Earth.