Exam 20: The Milky Waya Normal Spiral Galaxy

If the Large Magellanic Cloud is orbiting the Milky Way in a circular orbit with a speed of 175 km/s and a distance of 50 kpc from the center, how long would it take for the Large Magellanic Cloud to complete one orbit around the Milky Way?

The orbits of a few dozen stars have been carefully monitored over a few decades in the proximity of the supermassive black hole at the center of the Milky Way (see the figure shown below).One example is the so-called star SO-1, whose semimajor axis is 3,300 AU long and has a period of 94.1 years.What is the estimated mass of the central supermassive black hole?

What are the main observational difficulties in observing the shape and spiral arm pattern of the Milky Way?

The Milky Way and Andromeda are on a collision course.When will the initial collision happen?

Spiral arms are generated by

Which of the following is evidence that the object known as Sagittarius A* is a supermassive black hole?

Because of the ages of globular clusters in the Milky Way, we think our galaxy's early formation history was characterized by

As technology is advancing, scientists find more and more systems of very faint dwarf galaxies in the Local Group (some bound to the Milky Way).Could the stars in these potentially numerous, faint dwarf galaxies represent the "missing mass" (dark matter) in our Galaxy? Why or why not?

Outline the major differences between the thin and the thick disks of the Milky Way Galaxy.

What is ripping apart the Sagittarius dwarf spheroidal galaxy?

On average, we expect that ________ stars have the ________ percentage of heavy elements.

Suppose it was discovered that the galaxy has constantly been absorbing large amounts of pristine gas that never had any stars form in it.Would this complicate our interpretation of ages and chemical enrichment?

Studying standard candles in globular clusters offered the first conclusive proof that our galaxy was much ________ than originally believed.

The oldest stars in the galaxy are usually ________ in heavy elements because ________.

The Milky Way has both a thin and thick disk of stars.Which of the following statements about them is true?

The dark bands pictured in the figure below are strong evidence that the Milky Way is a(n) ________ galaxy.

In the figure below, we expect the absorption lines in the indicated star's spectrum to be

How do we know that at least one generation of stars formed and died before the Milky Way's globular clusters formed?

How do we know that globular cluster stars are not the first stars that have ever formed? Would this understanding change if some or all globular clusters came into the galaxy by accretion of small satellite galaxies?

The oldest disk stars are both ________ and ________ compared with halo stars.