ast hw1 – Flashcards

1. In science, observations on which all observers can agree are referred to as -observed facts -hypotheses -models -beliefs

2. An astronomical unit is -any planet's average distance from the Sun. -Earth's average distance from the Sun. -any large astronomical distance.

3. The star Betelgeuse is about 600 light-years away. If it explodes tonight, -we'll know because it will be brighter than the full Moon in the sky. -we'll know because debris from the explosion will rain down on us from space. -we won't know about it until about 600 years from now.

4. If we represent the solar system on a scale that allows us to walk from the Sun to Pluto in a few minutes, then -the planets are the size of basketballs and the nearest stars are a few miles away. -the planets are marble-size or smaller and the nearest stars are thousands of miles away. -the planets are microscopic and the stars are light-years away.

5. The total number of stars in the observable universe is roughly equivalent to -the number of grains of sand on all the beaches on Earth. -the number of grains of sand on Miami Beach. -infinity.

6. When we say the universe is expanding, we mean that -everything in the universe is growing in size. -the average distance between galaxies is growing with time. -the universe is getting older.

7. If stars existed but galaxies did not, -we would probably still exist anyway. -we would not exist because life on Earth depends on the light of galaxies. -we would not exist because we are made of material that was recycled in galaxies.

8. Could we see a galaxy that is 50 billion light-years away? -Yes, if we had a big enough telescope. -No, because it would be beyond the bounds of our observable universe. -No, because a galaxy could not possibly be that far away.

9. The age of our solar system is about -one-third of the age of the universe. -three-fourths of the age of the universe. -two billion years less than the age of the universe.

10. The fact that nearly all galaxies are moving away from us, with more distant ones moving faster, helped us to conclude that -the universe is expanding. -galaxies repel each other like magnets. -our galaxy lies near the center of the universe.

11. Which of the following statements about the celestial sphere is NOT true? -When we look in the sky, the stars all appear to be located on the celestial sphere. -The earth is placed at the center of the celestial sphere. -The celestial sphere does not exist physically. -The "celestial sphere" is just another name for our universe. -From any location on Earth, we can see only half the celestial sphere at any one time

12. The earth is made mostly of materials composed of elements more massive than hydrogen and helium. Where did these elements come from? -They were produced in the Big Bang. -They were created by chemical reactions in interstellar space. -They were produced by nuclear fusion in stars. -They were made by our Sun.

13. Which of the following correctly lists our "cosmic address" from small to large? -Earth, solar system, Milky Way Galaxy, Local Group, Local Supercluster, universe -Earth, solar system, Local Group, Local Supercluster, Milky Way Galaxy, universe -Earth, Milky Way Galaxy, solar system, Local Group, Local Supercluster, universe.

14. The diurnal (daily) motion of stars is due to -the motion of the earth around the sun -the rotation of the earth -the epicyclic nature of the celestial sphere -the rotation of the celestial sphere

15. Our solar system is larger than some galaxies. -True -False

16. In science, conceptual representations of observed phenomena are referred to as -facts -models -tests -beliefs

17. What happens during the apparent retrograde motion of a planet? -The planet rises in the west and sets in the east. -The planet temporarily reverses its usual eastward motion in the sky with respect to the stars. -The planet moves backward in its orbit around the Sun. -The planet moves through constellations that are not part of the zodiac.

18. If you could see stars during the day, the drawing below shows what the sky would look like at noon on a given day. The Sun is near the stars of the constellation Gemini. Near which constellation would you expect the Sun to be located at sunrise on the same day? (THINK! How does the sun move relative to the stars?) -Leo -Cancer -Gemini -Taurus -Pisces