If the spiral density wave were the only thing producing spiral ...

[Zoey63294]

If the spiral density wave were the only thing producing spiral arms, it would be expected that
 
  a. all spiral arms would be gas and dust free.
  b. all galaxies would have only two smooth spiral arms.
  c. the Milky Way would show and irregular pattern of short arms .
  d. the Milky Way wouldn't have any spiral arms.
  e. the halo component of the Milky Way would show spiral arms as well.

Question 2

What information can we get from eclipsing binaries that we cannot get from visual binaries?
 
  What will be an ideal response?

[FergA]

Answer to Question 1

b

Answer to Question 2

Because the orbital plane of eclipsing binaries is edge on from our viewpoint, we can determine the true orbital velocity, and hence the size of the orbits and the masses of the stars.

[Zoey63294]

Thanks

[FergA]

Welcome