What did Harlow Shapley study in order to deduce the Milky Way's size and the Sun's position in it?
A. globular star clusters
B. interstellar gas clouds
C. open star clusters
D. spiral arms
Answer: A
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Via the rotation curve method, we can estimate the mass of galaxies like M31 from
a. Doppler shifts of material at the edge of its disk and computing P = 2?r/v. b. the distances of the Doppler shift points from its center. c. Doppler shifts of material at the edge of its disk and computing P = 2?r/v and the distances of the Doppler shift points from its center. d. It is impossible to estimate the mass of M31.
Why do astronomers believe that the Jovian planets must contain rocky material in their cores?
A. Because the Jovian planets have large magnetic fields. B. Because silicates and irons were part of the overall composition of the Solar nebula. C. Because the Jovian planets have large gravity. D. The statement of the question is incorrect. Astronomers believe that the Jovian planets consist exclusively of hydrogen and helium.
Which of the following particles is most similar to an electron?
A) photon B) muon C) quark D) proton E) neutrino
When a gas undergoes an isothermal process, there is
A) no work done by (or on) the gas. B) no heat added to the gas. C) no change in the volume of the gas. D) no change in the temperature of the gas. E) no change in the pressure of the gas.