Chapter 12, Problem 1RQ

Why is it difficult to specify the dimensions of the disk and halo?

To determine

The region why difficult to specify the dimensions of the disk and halo?

Explanation of Solution

The halo primarily contains singular old stars and bunches of old stars ("globular groups"). The halo additionally contains "dark matter," the material that we can't see yet whose gravitational force can be estimated. The Milky Way's halo might be more than 130,000 light years across.

The Milky Way's circle is 100,000 light a very long time crosswise over and 1,000 light years thick. Disks contains for the most part young stars, gas and dust, these are concentrated in winding arms. Some old stars are additionally present.

As we know, we are in the milky way galaxy, the view of the entire galaxy and universe is obstructed by gas and dust, thus it is difficult to specify the dimensions of the disk and halo.