Spiral Structure of Galaxies

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What is the primary reason why we do not observe the mass in the outer regions of galaxies in visible light?

It is obscured by the visible stellar systems.

It is too far away from the center of the galaxy.

It is not very luminous. (correct)

It is not in the plane of our Milky Way.

What would happen to the spiral arms of galaxies if they consisted of the same material?

They would wind up very tightly. (correct)

They would disappear over time.

They would remain straight and unwound.

They would change into elliptical galaxies.

Why do the orbital periods of stars in galactic disks vary?

Because of the age of the stars in the galaxy.

Because of the density of stars in the galaxy.

Because of the uniform rotation of the galaxy.

Because of the differential rotation of the galaxy. (correct)

What is the implication of not observing tightly wound spiral arms in galaxies?

Spiral structure is a transient phenomenon, or it is a wave phenomenon, or both. Signup and view all the answers

What is the name of the scientist who described the orbits of stars in self-gravitating stellar disks?

Per Olaf Lindblad Signup and view all the answers

What type of motion do stars in self-gravitating stellar disks exhibit?

Epicyclic motion Signup and view all the answers

What is the shape of the distribution of globular clusters in the galaxy according to Shapley's findings?

Spherical Signup and view all the answers

What was the significance of Shapley's discovery of the globular cluster distribution?

It showed we are not at the center of the universe Signup and view all the answers

What advantage did Shapley have over Kapteyn in determining the distribution of globular clusters?

He looked at objects located out of the plane of our galaxy Signup and view all the answers

What did Jan Oort measure to determine the dynamics of the galactic disk near the sun?

The Doppler shifts of the stars Signup and view all the answers

What was the model of the disk of our galaxy near the sun according to Jan Oort's research?

A circular shape with circular orbits Signup and view all the answers

What was the shape of the distribution of bright, giant stars observed by Jan Oort?

Flattened Signup and view all the answers

What is thought to be responsible for the strength and beauty of the spiral in the Whirlpool Galaxy, M51?

The passage of the companion galaxy Signup and view all the answers

What was the limitation of the computer simulation of the passage of the smaller galaxy past M51?

It was unable to reproduce the very prominent spiral structure in the inner regions of M51 Signup and view all the answers

What is the purpose of using computer simulations in astronomy?

To test theoretical models of galaxy formation and evolution Signup and view all the answers

What is the predicted outcome of the passage of the companion galaxy by M51?

The exhibition of a very strong spiral structure in M51 Signup and view all the answers

What is the main difficulty in using General Relativity to calculate the behavior of two very compact massive objects in close proximity?

The complexity of the calculations Signup and view all the answers

What is the focus of the discussion of General Relativity in this context?

The principle of equivalence and the definition of a straight line Signup and view all the answers

Spiral Structure of Galaxies

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