Using the data and the number of stars in the Galaxy estimated in the question 7, determine the average distance \(d\) (in pc) between star to star assuming for the Galaxy a flat disk of height \(300 \mathrm{pc}\). The average observed distance between stars in our Galaxy exceeds pc. Is the result obtained consistent with the observations?

Question 7:

As the Earth revolves around the Sun, the Sun revolves around the center of our Galaxy (where the black hole described in Fig. 11.12 resides). The Sun’s distance from the Galactic center is

and the speed of solar revolution is 

Using these data, estimate the total mass upper M_s Galaxy matter enclosed in the sphere of radius D. Assuming that the stars all have the same mass as the Sun,

estimate the number upper N_s in the Galaxy if all the mass determined above were concentrated in the stars. The estimated number of stars in our Galaxy by electromagnetic radiation is between 100 and 400 billion stars. Is the result obtained compatible with this estimate?

 Fig. 11.12

Transcribed Image Text:

D = 8.5 kpc (1pc= 3.0 1016 m),