If the elliptical galaxy in Hydra, whose image and spectrum are shown at the bottom of Figure 23-16 (Universe, 11th ed.), were to be at a distance of 3 billion ly, what would be the value of the Hubble constant H₀? (Be careful with units.)

Question

Quizplus · Accepted Answer

The Hubble constant can be calculated using the formula H0 = v/d, where v is the velocity and d is the distance. Given the distance is 3 billion light-years, convert it to megaparsecs (Mpc) and use the velocity from the spectrum to find H0. The correct calculation gives approximately 20 km/s/Mly.

If the Elliptical Galaxy in Hydra, Whose Image and Spectrum