Question

Imagine a photon of light traveling the different paths in the Milky Way described in the following list. Rank the paths based on how much time the photon takes to complete each journey, from longest to shortest.

A. across the diameter of the galactic halo
B. across the diameter of the galactic disk
C. from the Sun to the center of the galaxy
D. across the diameter of the central bulge
E. through the disk from top to bottom

Answer 1

The time it takes for a photon to complete journeys through the Milky Way is longest when crossing the galactic halo and shortest when traveling through the disk from top to bottom, with the other paths falling in between based on their respective distances.

Step-by-step explanation:

To rank the paths a photon of light takes to complete each journey through the Milky Way from longest to shortest, we must consider the scale of each component of the galaxy. The Milky Way can be roughly divided into the disk, the central bulge, and the halo. The halo is the most extensive and diffuse component, while the disk is where most of the visible stars and matter are located, and the bulge is the dense center.

Consider the following dimensions:

• The galactic halo has a diameter greater than the disk, likely reaching hundreds of thousands of light-years.
• The galactic disk is about 100,000 light-years in diameter and 2,000 light-years thick.
• The distance from the Sun to the center of the galaxy is about 25,000 to 28,000 light-years.
• The central bulge has a smaller diameter than the disk; it's thousands of light-years wide but not as wide as the disk itself.
• The thickness of the disk, or traveling from top to bottom, is about 2,000 light-years.

Using the above dimensions, the ranking from longest to shortest journey for a photon of light would thus be:

1. Across the diameter of the galactic halo
2. Across the diameter of the galactic disk
3. From the Sun to the center of the galaxy
4. Across the diameter of the central bulge
5. Through the disk from top to bottom

Answer 2

Longest : A. across the diameter of the galactic halo

B. across the diameter of the galactic disk

D. across the diameter of the central bulge

C. from the Sun to the center of the galaxy

Shortest : E. through the disk from top to bottom

Step-by-step explanation:

• A halo is larger than the diameters of the disk and a disk is larger than diameters of central bulge and the sun being at the center of the universe is in the form of the disk but is outside the bulge.

• The disk is small and thinner as compared to its diameters that are about 1000 light-years in thickness and this property makes it flat.