Exam 16: The Milky Way Galaxy

In which constellation in the Earth's sky is the center of the Milky Way Galaxy located?

Astronomers aim a radio telescope at a distant region of the Milky Way Galaxy and detect 21-cm radio waves with no Doppler shift. Which one of these possible explanations is NOT correct?

Why is it that astronomers rely upon the 21-centimeter line associated with the spin flip in hydrogen and not the more familiar hydrogen Balmer lines to gather information from the far side of the galactic plane?

The first suggestion that there were collections of stars beyond the Milky Way in the universe was made by

A rotation curve is a plot of the rotational velocity of a galaxy as a function of the distance away from the galactic center. What does the rotation curve of the Milky Way Galaxy look like?

If the Sun were traveling around the galactic center along with companion stars (all in circular orbits) as depicted in Figure 16-19 from the text, from which of these stars would one measure the largest Doppler shift of their light?

What important role do Cepheid variables stars have in astronomy?

Which of these do astronomers NOT find in orbit around the galactic center?

The observation by Hubble that demonstrated for the first time that the Andromeda "nebula" was at a very large distance from the Sun and outside the Milky Way Galaxy was that

Which of these observations was key to estimating the size of Sagittarius A*?

Henrietta Leavitt worked out the period-luminosity relation for the Type I (or classical) Cepheids found in the Small Magellanic Cloud. Later, Cepheids were discovered in globular clusters, and these were assumed to be Type I Cepheids, and the distances to these clusters were calculated accordingly. However, it was later discovered that these were dimmer Type II Cepheids. Refer to Figure 13-28 from the text. Did this require a recalculation of the distances to these Cepheids?

Which of these properties is NOT characteristic of the center of the Milky Way Galaxy?

The spiral-arm structure of the Milky Way Galaxy has been measured and evaluated MOST effectively by observations of

When a hydrogen atom is excited by some addition of energy and it responds with electron transitions between electron energy levels, the radiation it emits is usually in which regions of the electromagnetic spectrum?

Where do black holes with masses more than 100 times the mass of the Sun occur in the Milky Way Galaxy?

The famous Shapley-Curtis debate in 1920 concerned which fundamental astronomical question in astronomy?

The galactic halo contains outer and inner shells of stars. How does the outer shell compare to the inner shell?

The Milky Way, the galaxy in which the Sun resides, is an example of which type of galaxy?

The method used by Harlow Shapley in 1917 to estimate the Sun's location in the Milky Way Galaxy was the measurement of the

The significant feature of a Cepheid variable is that there is a relationship between two intrinsic parameters, one of which can be easily measured, while knowledge of the other parameter is required. These parameters are