Assuming a radial speed of a galaxy to be 100 km/s from us and Hubble's constant to be 23 km/s/10⁶ c · y, how far is the galaxy from us? A) 2300 ly B) 2300 Mly C) 4.3 Mly D) 0.23 Mly E) None of these is correct.

Question

Quizplus · Accepted Answer

We can use Hubble's Law to calculate the distance to the galaxy:

v = H0d

where v is the radial speed, H0 is Hubble's constant, and d is the distance.

Rearranging the equation:

d = v / H0

Substituting the values given:

d = 100 km/s / (23 km/s/10^6 pc)

d = 4.35 Mpc

Converting Mpc to Mly:

d = 14.2 Mly / Mpc

d = 4.35 Mpc x 14.2 Mly/Mpc

d = 61.8 Mly

Therefore, the answer is C) 4.3 Mly.

Assuming a Radial Speed of a Galaxy to Be 100