Question : The Southern Cross is a Southern Hemisphere constellation that is as famous : 2146894
34) The Southern Cross is a Southern Hemisphere constellation that is as famous the big dipper in the Northern Hemisphere because of the brightness of the stars. It has a Southern Hemisphere declination slightly higher than the big dipper's Northern Hemisphere declination. Is it visible anywhere in the United States?
A) Yes, it is visible in most of the southern tier of states during summer months.
B) Yes, it is visible during much of the year, but it is obscured by the full Moon.
C) Yes, it is visible in Hawaii during the summer months.
D) No, it is not visible anywhere in the U.S. because the entire country is too far north.
35) What is the right ascension and declination for Polaris, the North Star?
A) RA indeterminate, D 90 degrees
B) RA 0 hr, D 0 degrees
C) RA 0 hr, D 80 degrees
D) RA 90 hr, D -90 degrees
36) Earth hits its perihelion position in January. Solar radiation is proportional to the distance squared between the Sun and the earth, so why isn't it hot in "winter" at perihelion?
A) Precession modifies the effect as Earth wobbles on its axis.
B) The ellipticity of the orbit is small, so the affect is small; seasons are caused by tilt of Earth's orbit.
C) It is; it is called summer in the Southern Hemisphere, and there is just a time lag for the Northern Hemisphere.
D) None of these is correct.
37) The Big Dipper is near the ________ celestial pole.
38) Where will the North Star be, relative to the celestial coordinates, 12,000 years from now?
A) Right where it is now; it isn't going anywhere.
B) 23 1/2 degrees away from the pole, due to precession.
C) Several degrees from the North Pole position, and Vega will be the North Star instead of Polaris.
D) None of these is correct.
39) The ________ day is the time it takes for Earth to make one complete rotation with respect to a star other than our Sun.
D) synodic E) sidereal
40) A very slow motion of Earth's axis that requires 26,000 years to complete is called ________.
A) retrograde motion
C) Ptolemaic motion
D) axial precession
41) The apparent path of the Sun upon the celestial sphere is called the ________.
42) A statement you will sometimes hear people say is that a day is not 24 hours but is really 23 hr. 56 min. and 4 sec. What does this refer to?
A) This is sidereal time, not solar time; a solar day is 24 hours.
B) Our clocks drift that much each day, and we average out the affect with period time shifts, like leap years and leap seconds.
C) It is just an urban myth; the day really is 24 hours long.
D) The original definition of the hour was off, and with more accurate atomic clocks we now realize the real day is this length.
43) A sidereal day is defined as ________.
A) the time between periods when the Sun is at the exact same height in the sky, for example, noon
B) 24 hours at Greenwich, England
C) the time for one complete revolution of the earth relative to the celestial reference
D) 24 hours in a day