Lessons 23 and 24 Homework Quiz

Harlow Shapley concluded that the earth is not at the center of the Galaxy because:

The earth is not at the center of the distribution of globular clusters.

Hubble's Law states that:

The farther away a galaxy, the greater its redshift

Your instructor has discovered a previously unknown

supercluster of galaxies

The local group of galaxies

- Contains about 50 galaxies. - Includes the Milky Way Galaxy and the Andromeda Galaxy.

Roughly how far is the sun from the center of the Milky Way Galaxy?

10 kpc

What observation clinched the idea that the "spiral nebulae" were actually external galaxies rather than part of the Milky Way?

Hubble's discovery of Cepheid variables in M 31

Cepheid variables are used as distance indicators because of their

Period-luminosity relation.

Which galaxy type would generally appear most red when observed?

elliptical

Compared with a globular cluster, a galactic (open) cluster

has a lower density of stars

On a photograph of a dense part of the Milky Way, you see a dark patch which seems to contain few stars. Probably you are seeing

obscuration by a dust cloud.