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Astronomy 110G MIDTERM 1 October 3, 2007


Multiple choice questions. 2 points each

  1. A shooting star is
    1. a star that is exploding
    2. a star that is just being formed out of the interstellar matter
    3. a figment of our imagination
    4. a comet that is colliding with another planet
    5. a meteor that is burning up as it passes through the Earth's atmosphere

  2. An astronomical unit is
    1. the time it takes for light to travel from the Sun to the Earth
    2. the distance that light travels in one year
    3. the average distance between the Earth and the Sun
    4. the size of the solar system
    5. any large measure of distance
  3. Imagine your camera is pointing at the North Star (Polaris), but is looking at a bunch of stars around it as well. If you leave the shutter open for 6 hours, what will the photo look like?
    1. The stars near the North Star will make complete circles in the photos.
    2. The stars near the North Star will make half circles in the photos.
    3. The stars near the North Star will make quarter circles in the photos.
    4. The stars near the North Star will make straight lines in the photos.
    5. The stars near the North Star will remain point-like dots of light.

  4. If we established an observatory on Pluto and observed stars from two opposite points in Pluto's orbit
    1. we would observe that stars have larger parallactic motion than as seen from Earth
    2. we would observe that stars have smaller parallactic motion than as seen from Earth
    3. we would observe that stars have no parallactic motion
    4. we would observe that all the stars were much brighter than as seen from Earth

  5. Which of the following best describes the cause for the seasons here on Earth?
    1. The distance between Earth and the Sun changes during the year.
    2. More sunlight reaches Earth during some times of the year than others.
    3. Earth's rotational axis is tilted with respect to the plane of Earth's orbit around the Sun.
    4. The Sun gives off different amounts of sunlight during different times of the year.
    5. Some times of the year Earth orbits the Sun more slowly than other times of the year.

  6. Jupiter has an almost circular orbit around the Sun, and its rotation axis is almost perfectly perpendicular to its plane of revolution. Which of the following would you expect to be true?

    1. Jupiter should have very extreme seasons, much hotter in summer than in winter
    2. Jupiter should not have seasons at all, and it should be the same temperature at the North Pole of Jupiter as it is at the equator of Jupiter
    3. Jupiter should not have seasons at all, but it should still be colder at the North Pole of Jupiter than it is at the equator of Jupiter
    4. It should be just as warm at night on Jupiter as it is during the day

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  7. If you could see stars during the day, this is 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 sunset? Remember to consider motions of both Sun and stars across the sky.
    1. Leo
    2. Cancer
    3. Gemini
    4. Taurus
    5. Pisces

  8. Which of the following best describes why the Moon goes through phases?
    1. The Earth blocks some of the Sun's light from reaching the Moon.
    2. The sunlight reflected from Earth lights up the Moon but is less effective when the Moon is lower in the sky than when it is higher in the sky.
    3. We see only part of the lit-up face of the Moon depending on its position relative to Earth and the Sun.
    4. Clouds occasionally cover different parts of the moon to give it phases.
    5. The Moon is somewhat flattened and disk-like, and appears more or less round depending on the precise angle from which we see it.

  9. When does the full moon rise over the horizon?
    1. midnight
    2. sunrise
    3. noon
    4. sunset

  10. Kepler's first law says that
    1. planetary orbits are elliptical with the Sun at the center of the ellipse
    2. planetary orbits are elliptical with the Sun at one of the focii of the ellipse
    3. planetary orbits are circular with the Sun at the center of the circle
    4. a planet moves fastest when farthest from the Sun
    5. more distant planets go around the Sun faster than planets which are closer to the Sun
    True or false questions. 2 points each

  11. Stars in the disks of spiral galaxies move in roughly circular orbits around the center of the galaxy. T or F

  12. We know that the Milky Way is at the center of the Universe because when we look around, we see that all other galaxies are moving away from us. T or F

  13. A light year is a measure of distance.T or F

  14. The Moon exhibits retrograde motion. T or F

  15. All stars in the Milky Way galaxy are exactly like our Sun, and they appear to have different brightnesses only because they are at different distances. T or F

    Short answer questions. Answer these concisely in the space given. You should be able to answer in a few sentences. Make sure to think before you write, and then write your thoughts clearly. 5 points each

  16. Why doesn't the North Star appear to move in the sky? If you lived at the North Pole, would the North Star appear to move? Would it appear in the same location in the sky at the North Pole as it appears from Las Cruces?

  17. When it is summer in the northern hemisphere, what season is it in the southern hemisphere? Explain why, being specific and clear; use a diagram if it will help

  18. What is a lunar eclipse? Why isn't there an eclipse of the Moon every time the Moon is full? Draw a diagram to support your answer.

  19. Describe what is meant by the term retrograde motion. What objects does this term apply to? Why does this type of motion occur?

  20. Today (October 3) the Moon can be seen in the third quarter phase. Draw a diagram showing the relative positions of Sun, Moon, and Earth for a third quarter moon. At what times of the day/night will you be able to see the Moon today? On what date in October will we be able to see a first quarter Moon?

  21. Say you discover a new comet which has a period of exactly one year, and by observing it you find that it has a very eccentric (``squashed'') orbit. Carefully draw a single sketch showing the orbits of the earth and the comet. Make sure to put the location of the Sun on the sketch, and also to show the relative sizes of the two orbits; you can also tell us in words about the relative sizes of the two orbits. Remember Kepler's laws!


Jon Holtzman 2007-10-03