Astronomy 100

Section 2, Fall 2008

Homework B

Answers

1. The Earth is at the aphelion point of its orbit (farthest from the Sun) about
d) July 4 (1.7 percent farther than average)

2. The Zodiac runs along the
d) apparent path of the Sun (the ecliptic)

3. When viewed at the same time of night but two weeks apart, stars will appear to shift to the west by how many degrees?
e) 14 (since the Sun moves along the ecliptic at a rate of one degree per day) NOTE: typo error, will also allow answer "d".

4. The obliquity of the ecliptic is
c) 23.5 degrees

5. The vernal equinox is where the ecliptic meets the
e) celestial equator (with the Sun moving north)

6. The Foucault pendulum is evidence
e) for a rotating Earth

7. When is the Sun farthest north of the celestial equator?
a) June 21 (the first day of summer)

8. Where on the horizon will the Sun set in Chicago on June 21?
a) somewhere in the northwest (because the Sun is north of the equator)

9. On what date does the Sun set exactly west (except at the poles)?
d) March 20 (when the Sun is on the celestial equator)

10. The seasons are caused by
b) the obliquity of the ecliptic

11. When it is summer in Canada, what is the season in Australia?
c) winter

12. Where can the Sun NOT be seen overhead sometime during the year?
b) Chicago (The Sun can be seen overhead only between the tropics)

13. Where can the Sun be circumpolar sometime during the year?
e) the Antarctic Circle

14. If the obliquity of the ecliptic were 11 degrees, what would be the latitude of the northern tropic?
d) 11 degrees north

15. What is the maximum altitude the Sun can ever attain at either of the Earth's rotation poles?
b) 23.5 degrees (since the celestial equator lies on the horizon)

16. It is colder in winter than in summer because
e) the low angle of the Sun relative to the horizon makes sunlight spread out over a larger area

17. Where in general would you get the worst sunburns?
e) equator (because the Sun is most nearly overhead)

18. Where (at what latitude) on Earth are twilights the shortest?
a) 0 degrees (at the equator, where stars and the Sun set vertically)

19. Which constellation is most related to Ursa Minor?
a) Ursa Major
b) Canis Minor (both allowed)

20. What constellation contains the North Celestial Pole?
c) Ursa Minor

21. Which constellation is circumpolar (does not set) from Urbana?
b) Ursa Minor (because it is so close to the celestial pole)

22. Which constellation cannot be seen from Urbana?
c) Crux (the Southern Cross)

23. Which constellation contains the Winter Solstice?
e) Sagittarius

24. The Big Dipper is in
e) Ursa Major

25. Which is not a constellation of the Zodiac?
d) Cepheus