Which of the following statements about stellar parallax is true? A. We observe all stars to exhibit at least a slight amount of parallax. B. Stellar parallax was first observed by ancient Greek astronomers. O C. The amount of parallax we see depends on how fast a star is moving relative to us.

Because of the precession of the Earth’s axis,   a. there are four seasons, spring, summer, fall, and winter.   b. the Earth receives more solar radiation in the summer than in the winter.   c. Polaris will not be the North Star in about 12,000 years.   d. the lengths of the Earth’s days and nights vary throughout the year.

5. The approximate relationship between the luminosity and the period of Cepheid variables is Lstar[in units Lsun] = 335 P [in units days]. Delta Cephei has a cycle period of 5.4 days and a parallax of 0.0033 arcseconds. A second Cepheid appears 1/1000 times as bright and has a period of 54days. How far away (in parsecs) is the second more distant Cepheid?

Stars A and B both have the same spectral class. Star A is 7 times farther away than star B. The brightness of star A will be ________ times dimmer than B. a. 100 b. 14 c. 7 d. 49 e. 10