Download Astro 101-001 Summer 2013 (Howard) Assignment #3 Due: Wed

Astro 101-001 Summer 2013 (Howard)
Assignment #3
Due: Wed., July 3rd (7/3/2013)
1. Adams and Leverrier both predicted the position of Neptune, based on its
effects on: (a) the Sun; (b) Jupiter; (c) Saturn; (d) Uranus; (e) Pluto.
2. Which of these is the most unusual feature of Pluto's orbit? (a) It lies exactly
on the ecliptic; (b) It has the lowest eccentricity of any planet's orbit; (c) It is more
inclined to the ecliptic than any of the eight planets; (d) It has an unexpectedly
short orbital period; (e) Its orbital period is exactly twice that of Neptune's.
3. How were the rings of Uranus discovered?
4. The temperature of the Sun’s photosphere (surface temperature) is about: (a)
3,200 K; (b) 5,800 K; (c) 11,000 K; (d) one million K; (e) ten million K.
5. Sunspots are dark splotches on the Sun. Which statement is true? (a) They
are hotter than the surrounding areas of the Sun; (b) They are extremely cold
objects, as cold as Pluto; (c) They are extremely hot, but cooler than the
surrounding areas of the Sun; (d) They are solid bodies floating on the surface of
the Sun; (e) They are associated with areas of very low magnetic fields.
6. The primary source of the Sun's energy is: (a) oxidation of carbon in the core;
(b) gravitational collapse of the helium coreward; (c) dark energy; (d) nuclear
fusion of hydrogen into helium; (e) the weak force creating energy from uranium
decay.
7. Name two features of the Sun and/or the Earth’s magnetosphere that are more
numerous when the sun is active (i.e., near the peak of its activity cycle).
8. What is the period of sunspot number variations? What is the period of the
solar cycle?
9. A star has a parallax of 0.01 arc seconds. Its distance is: (a) 0.01 parsecs;
(b) 0.1 parsecs; (c) 1 parsec; (d) 10 parsecs; (e) 100 parsecs.
10. What do we mean when we say a star has proper motion?