Astronomy 100 Homework - Week 2

Choose the ONE most comprehensive response.

1. If you lived on the moon would the north star (Polaris) remain relatively stationary in the sky as it does from Earth?

   a.  Polaris would not remain stationary because the Moon's orbit around Earth is not aligned with its solar orbit.
   b.  Polaris would not remain stationary in the sky because the Moon's spin axis is not aligned with Earth's.
   c.  Polaris will remain stationary, along with all stars, because the Moon does not spin on an axis.
   d.  Polaris will remain stationary for all satellites of Earth, provided they orbit in the ecliptic plane.
   

2. How many orders of magnitude (powers of ten) is the distance to the moon greater than the distance across the Atlantic ocean?

   a.   2
   b.   3
   c.   4
   d.   5
   

3. An inhabitant of a planet orbiting the star Betelguese observes the flash from the first nuclear weapon on Earth, exploded in July 1945. If this extraterrestrial being were to send a signal to Earth immediately to confirm this sighting, and we were watching her planet, when would we expect to see the signal? (Betelgeuse is 520 light years distant)

   a.   2985 AD
   b.   2465 AD
   c.   2040 AD
   d.   1976 AD
   

4. Patterns of stars in constellations hardly change in appearance over times of even a few thousand years. WHY?

   a. Stars are fixed and do not move.
   b. Stars move, but they move slowly, only a few kilometers in a thousand years.
   c. The stars move rapidly but are so far away that it takes a long time to make a change in the patterns.
   d. Stars within a constellation move together as a group, which prevents the pattern from changing.
   

5. If the Moon is rising at noon, the phase of the Moon must be...

   a. new.
   b. first quarter.
   c. third quarter.
   d. full.
   

6. Is it possible to prove, for certain, that a scientific theory is false?

   a. No, because it is always possible that future experiments will agree with the theory.
   b. No, because science can never be certain of anything.
   c. Yes, by means of a single confirmed experiment that contradicts the theory.
   d. Yes, by performing a large number of experiments.
   

7. Why does the Moon always face the same side towards Earth?

   a. because the Moon’s rotation (spin on axis) and orbital periods are equal
   b. because the Sun only illuminates one half at a time
   c. because the Moon has a nearly circular orbit around the Earth
   d. because the Moon does not rotate on its axis
   

8. If the width of the Moon in the sky is 32 arc-minute, and the width of the Sun in the sky is 30 arc-minute, what kind of solar eclipse would an earth-based observer witness, assuming the observer is perfectly aligned with the Sun and Moon?

   a. a penumbral solar eclipse.
   b. a partial solar eclipse.
   c. an annular solar eclipse.
   d. a total eclipse.
   

9. Scientists always phrase their claims in a way that is falsifiable. Which of these statements is most "falsifiable"?

   a. Extraterrestrials are covertly infiltrating the government.
   b. Abraham Lincoln secretly believed woolly mammoths were still living in northern Canada.
   c. There is a teapot orbiting in the asteroid belt just beyond Mars.
   d. All crows are black.
   

10. In a dream, you land on a planet in a location such that all the stars you can see rotate in circular arcs in the sky, and they do not rise or set; a star directly overhead (your zenith) remains stationary. You then walk in one direction a distance of 3000 km to a location such that the stars you now see all set and rise at right angles relative to the E-W horizons. What is the circumference of this dream planet?
    a.    3,000 km
    b.    6,000 km
    c.    9,000 km
    d.    12,000 km
    

11. Which of the following does NOT help keep human bias from affecting scientific claims.

    a. double blind experiments
    b. peer review
    c. data sharing
    d. corporate funding
    

12. Is it possible to prove, for certain, that a scientific theory is true?

    a. Yes, by carrying out a sufficient number of independently confirmed experimental observations.
    b. Yes, by deducing it logically from other scientific theories that are known to be true.
    c. No, because experimentalists sometimes make serious mistakes.
    d. No, because it is possible that a future experiment will disagree with an aspect of the theory.
    

13. The Sun subtends (angular width) about 0.5 degree in diameter. On the equator of Earth, about how long does it take for the Sun to set, from time of first contact with the western horizon to the time the Sun completely disappears below that horizon?

    a.  2 seconds
    b.  2 minutes
    c.  4 minutes
    d.  about 1 hour
    

14. Which of the following refers to the apparent daily movement of objects in the sky, due to the rotation and orbit of the Earth.

    a.  sidereal motion
    b.  analemmic motion
    c.  diurnal motion
    d.  nocturnal motion
    

15. What is the difference between a theory and a fact?

    a.  A fact is a theory that has been scientifically proven.
    b.  A fact is an observation and a theory is an explanation.
    c.  A theory is a fact that has withstood the test of time.
    d.  A theory is always eventually disproven and facts are forever.
    

16. Suppose that at midnight you observe the Moon due south on the meridian. Where will it be two nights later at midnight?
    a.  It will be about 26 degrees west of my meridian.
    b.  It will be about 26 degrees east of my meridian.
    c.  It will be about 26 degrees north of my meridian.
    d.  It will be about 26 degrees south of my meridian.
    

17. Over a period of one year, how much of the overall (night) sky would a Bellingham observer be able to see?

    a. a little more than 50%
    b. between 75% and 100%
    c. 100%
    d. it depends on which year
    

18. When we watch the northern hemisphere nighttime sky, we find that...
    a. stars and constellations toward the south slowly rise in the east, pass the meridian, and set in the west.
    b. all stars and constellations reach their highest point in the sky at midnight.
    c. stars and constellations slowly rise in the west, pass overhead, and set in the east.
    d. the stars and constellations remain fixed in our sky because they are so far away.
    

19. You read in a Facebook meme that a full Moon is rising at midnight on Halloween.  What is wrong with this statement?

    a.  At Halloween, the Earth is near the fall equinox, so the Moon will rise near sunset.
    b.  Halloween corresponds with the harvest Moon, rising near sunset to enable night-time gathering of food.
    c.  At midnight for any observer, a full Moon will be transiting the meridian, not rising.
    d.  Nonsense - there is nothing wrong with the statement.
    

20. Why is it winter in Earth’s Northern Hemisphere when it is summer in the Southern Hemisphere?

    a. The Northern Hemisphere is further from the Sun than the Southern Hemisphere.
    b. The Northern Hemisphere is "on top" of the Earth and therefore receives more sunlight.
    c. The Northern Hemisphere is tilted toward the Sun and receives more direct sunlight.
    d. The Northern Hemisphere is tilted away from the Sun and receives more indirect sunlight.