Ch8 - Assignment: Chapter 8 Class: Astronomy I Date:...

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Class: Astronomy I Date: September 24 th , 2007 Review Questions 1. Describe three properties of the solar system that are thought to be a result of how the solar system formed. a) The terrestrial planets composed of rocky substances are relatively small, while the Jovian planets composed of hydrogen and helium are relatively large. b) All of the planets orbit the Sun in the same direction, and all of their orbits are in nearly the same plane. c) The terrestrial planets orbit close to the Sun, while the Jovian planets orbit far from the Sun. 2. The graphite in your pencil is a form of carbon. Where were these carbon atoms formed? The carbon atoms, along with other common atoms in the atmosphere were formed in the formation of the solar system. 3. What is the interstellar medium? How does it become enriched over time with heavy elements? Interstellar medium is a tenuous collection of gas and dust that pervades the spaces between the stars. The medium gets enriched as different stars die and supply with heavy elements. Observations show that new stars form as condensations in the interstellar medium. 4. What is the evidence that other stars existed before our Sun was formed? Because our solar system contains heavy elements, it must be that at least some of its material was once inside other stars that existed before the formation of the Sun. 5. Why are terrestrial planets smaller than Jovian planets? The Jovian planets are larger in size than terrestrial planets because they have their primary elements, hydrogen and helium, are very abundant. 6. How do radioactive elements make it possible to determine the age of the solar system? What are the oldest objects that have been found in the solar system? Radioactive elements make it possible for astronomers to see the different types of radioactive nucleus decays. The oldest objects found in the solar system are meteorites, the bits of interplanetary debris that survive passing through the Earth’s atmosphere and land on Earth’s surface. 7. What is the tidal hypothesis? What aspect of the solar system was it designed to explain? Why was this hypothesis rejected? Tidal hypothesis states that a star happened to pass close by the Sun, and that the star’s tidal forces drew a long filament out of the Sun. It was designed to explain why the planets orbit the Sun in the same direction and in nearly the same plane. This hypothesis was rejected because in 1930s, the tidal forces strong enough to pull a filament out of the Sun would cause the filament to disperse before it could condense into planets. 8. What is the nebular hypothesis? Why is this hypothesis accepted? Nebular hypothesis states that the solar system evolved as a hot rotating flattened gaseous nebula. As the nebula cooled, the Sun condensed at the center and planets and moons from contracting concentric rings at the rim. Last Name: Sung
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Ch8 - Assignment: Chapter 8 Class: Astronomy I Date:...

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