Name: ___________________ Date: __________ Astronomy Test Review Sheet 1. What is a comet? Draw a picture of one? A comet is a lump of ice, frozen gases, and dust that orbit the Sun. They have a characteristic tail that always points away from the Sun. 2. Two stars in the sky are identical in size and temperature. One is a million light years away. The other is 1 light year away. Which will appear Bigger and Brighter? Explain. The one that is 1 light year away because it is closer. 3. List the Gas Giants: Jupiter, Saturn, Uranus, Neptune 4. List the terrestrial planets: Mercury, Venus, Earth & Mars 5. Which force keeps each planet orBiting around the Sun? Gravity 6. A satellite is anything that orBits a planet. What natural satellite orbits our planet? The Moon 7. When a photographer takes a star trail photo he sees the motion of the star in his image (its trail). Is the star really moving as shown in the photo? Explain. No it is not. Earth’s rotation causes it to appear to move across the sky, which is what is captured in the time lapse photograph. 8. What is a revolution? The movement of one body around another. 9. What is a rotation? The spinning of an object on its own axis. 10. What is an orBit? The curved path a revolving body takes around another body. 11. How long does it take for the Earth to complete one revolution around the Sun? 365 days or 1 year. 12. How long does it take for the Earth to complete one rotation on its axis? 24 hours or 1 day 13. How would we classify the Sun? Hint-refer to characteristics of stars pages in your notes! The Sun is an average sized star. Looking at your notes you will see it is classified as a Main Sequence Star. 14. A comet was seen in the night sky in 1920. It was seen again in 2015. When will we see it again? 2015-1920= 95 years. 2015 + 95=2110. 15. What allows us to see planets and moons in the night sky? Explain. Sunlight reflected off of the moons and planets allows us to see them. 16. What two factors control the gravitational attraction Between two objects? Explain. a. The larger the mass of either object, the greater the gravitational force between them. b. The shorter the distance between the two objects, the greater the gravitational force. 17. Using the Solar System data chart worksheet, answer the following questions: a. Which planet’s diameter is aBout 10 times the diameter of Earth? Show your work: Earth’s equatorial diameter=12,756 km and Saturn is 120,000 km which is about ten times as big as Earth’s equatorial diameter because 12,756 x 10= 127,560. b. Which planet has a faster rotational speed: Earth or Uranus? Explain. Uranus has shorter period of rotation (time to rotate), which means it is rotating at a higher speed (faster). c. On which planet would you have the longest year? Neptune d. Which planet is has a density less than that of water? Saturn. Water has a density of 1 g/cm3 and Saturn’s density is less than that. 18. Explain in a few sentences, the structure and scale of the Universe. Use the following words: Sun, Milky Way Galaxy, Galaxy, Solar System, Universe The Sun is the star that Earth revolves around. Everything that revolves around the Sun makes up the Solar System. The Sun is one star in the Milk Way Galaxy. There are billions of galaxies in the Universe. 19. What are the three types of galaxies? What type is our home galaxy? Spiral, Elliptical, & Irregular. Our galaxy (the Milky Way) is a spiral galaxy 20. What does the color of stars tell us aBout their temperature? Be specific. Blue stars are hot, and red Stars are cool. 21. What is a constellation? A group of stars that forms a pattern in the sky. 22. What is angular elevation? The angle a star makes with the horizon. 23. Describe the motions of the Earth and the moon? The moon revolves around the Earth and the Earth revolves around the Sun. The Earth also rotates on its axis. .