Final answer:
To calculate the distance to a galaxy moving away at 30,000 km/s using Hubble's Law, divide the velocity by Hubble's constant of 22 km/s per million light-years, resulting in an approximate distance of 1,363.64 million light-years.
Step-by-step explanation:
To determine how far away a galaxy is, if it's observed to be moving away from us at 30,000 km/s, we can use Hubble's Law.
Hubble's Law is expressed as v = H x d, where v is the recessional velocity of the galaxy, H is Hubble's constant, and d is the distance to the galaxy.
The most recent work on Hubble's constant suggests a value of about 22 km/s per million light-years.
To find the distance to the galaxy, rearrange the equation to solve for d: d = v / H.
Using the given velocity of 30,000 km/s and assuming Hubble's constant H is 22 km/s per million light-years, the calculation is as follows:
d = 30,000 km/s ÷ 22 km/s per million light-years
d = 1,363.64 million light-years
Therefore, the galaxy is approximately 1,363.64 million light-years away from us.