One astronomer (astronomer A) claims that the Hubble constant is 84 km/s/Mpc, while another (astronomer B) claims that it is 63 km/s/Mpc. If, based on the Hubble constant, astronomer A claims that a particular galaxy is 3.00 billion ly away, then astronomer B would claim that it is:

Question

Quizplus · Accepted Answer

The Hubble constant relates the speed at which a galaxy is moving away from us to its distance. If astronomer A, using a higher Hubble constant, calculates a distance of 3.00 billion light-years, then astronomer B, using a lower Hubble constant, would calculate a larger distance for the same galaxy. The relationship between the Hubble constant and distance is inversely proportional, so if the Hubble constant decreases from 84 to 63 (a factor of 84/63 = 4/3), the calculated distance increases by the same factor, making the new distance 3.00 billion ly * 4/3 = 4.00 billion ly.

One Astronomer (Astronomer A) Claims That the Hubble Constant Is