PHYS 107 ASTRONOMY CHAPTER 1

• Question 1

  1 out of 1 points

  	If we live on the equator we can see:
  	Selected Answer:   Every star. Correct Answer:  Every star. Response Feedback: Correct, from the equator you can see (on the horizon) the north and south pole and so can see every star in the sky.

• Question 2

  1 out of 1 points

  	What fraction of the celestial sphere can you see at any given time?
  	Selected Answer:   exactly 1/2 Correct Answer:  exactly 1/2 Response Feedback: Correct, since the Earth is a sphere we can see from it's surface exactly 1/2 of the sky.

• Question 3

  1 out of 1 points

  	A constellation which is on the Eastern horizon at sunset will be:
  	Selected Answer:   just above the Eastern horizon at sunset one month later. Correct Answer:  just above the Eastern horizon at sunset one month later. Response Feedback: Correct, the Sun appears to move one constellation (30 degrees on the sky) each month, and given the direction of the Earth's motion around the Sun constellations rise ~1 hour earlier each month.

• Question 4

  1 out of 1 points

  	A star that you see directly overhead tonight will:
  	Selected Answer:   be directly overhead approximately one year later at the same time Correct Answer:  be directly overhead approximately one year later at the same time Response Feedback: Correct, a star will appear directly overhead approximately one year later as the Earth orbits the Sun over one year.

• Question 5

  1 out of 1 points

  	The Sun moves through a constellation in approximately:
  	Selected Answer:   1 month Correct Answer:  1 month Response Feedback: Correct, there are 12 constellations in the zodiac, and the Sun moves through them approximately once a month.

• Question 6

  1 out of 1 points

  	Which of the following statements uses the term light-year correctly?
  	Selected Answer:   It's about 4 light-years from here to the nearest star to the Sun. Correct Answer:  It's about 4 light-years from here to the nearest star to the Sun. Response Feedback:  Correct, it takes light about 4 years to travel from the star Alpha Centauri as compared to only 8 minutes from the Sun.

• Question 7

  1 out of 1 points

  	A star returns to the same point on the sky in approximately:
  	Selected Answer:   One day Correct Answer:  One day Response Feedback: Correct, the Earth rotates once over 1 day so a star will be close to (but not exactly) at the same point one day later.

• Question 8

  1 out of 1 points

  	Which of the following statements about circumpolar stars is true at all latitudes?
  	Selected Answer:    They always remain above your horizon. Correct Answer:    They always remain above your horizon. Response Feedback:  Correct, circumpolar stars can rotate around either pole and never set.

• Question 9

  1 out of 1 points

  	The zenith is always:
  	Selected Answer:   straight overhead. Correct Answer:  straight overhead. Response Feedback: Correct, the zenith is just the point straight overhead.

• Question 10

  0 out of 1 points

  	Constellations are:
  	Selected Answer:   Unchanging parts of the celestial sphere. Correct Answer:  Groups of stars in the same part of the sky as seen from Earth today. Response Feedback: Incorrect, this is one of the trickier questions in this homework assignment.  Constellations are really arbitrary groups of stars (at varying distances), and are not physically associated with each other.

• Question 11

  1 out of 1 points

  	The horizon is:
  	Selected Answer:   An imaginary plane which defines which portions of the sky one can see at any given time. Correct Answer:  An imaginary plane which defines which portions of the sky one can see at any given time. Response Feedback: Correct, the horizon divides the parts of the sky you can see from that you cannot, and depends on you position on the Earth.

• Question 12

  1 out of 1 points

  	A star which is circumpolar in Louisville will be:
  	Selected Answer:   Below the horizon at the South Pole. Correct Answer:  Below the horizon at the South Pole. Response Feedback: Correct, a star which is circumpolar in the northern hemisphere will  be below the horizon at the South pole.

• Question 13

  1 out of 1 points

  	The star Polaris is:
  	Selected Answer:   A circumpolar star for the Northern hemisphere. Correct Answer:  A circumpolar star for the Northern hemisphere. Response Feedback: Correct, Polaris is currently near the north celestial pole, and so is a circumpolar star for essentially all of the northern hemisphere.

• Question 14

  1 out of 1 points

  	Which of the following statements about the celestial equator is true at all latitudes?
  	Selected Answer:    It represents an extension of Earth's equator onto the celestial sphere. Correct Answer:    It represents an extension of Earth's equator onto the celestial sphere. Response Feedback:  Correct, the celestial equator is just the Earth's equator out to the stars

• Question 15

  1 out of 1 points

  	If a star moves from above to below the horizon we call this:
  	Selected Answer:   Setting Correct Answer:  Setting Response Feedback: Correct, setting is moving below your horizon (like the setting Sun or Moon).