Understanding Hubble's Law
Hubble's Law states that the recessional velocity (v) of a galaxy is directly proportional to its distance (d) from us. This relationship is expressed as:
* v = H₀ * d
Where:
* v is the recessional velocity (km/s)
* H₀ is Hubble's constant (km/s/Mly)
* d is the distance to the galaxy (Mly - millions of light-years)
Applying the Law to the Problem
1. Given:
* H₀ = 22 km/s/Mly
* d = 1 billion light-years = 1000 Mly
2. Substitute the values into the equation:
* v = (22 km/s/Mly) * (1000 Mly)
3. Calculate the recessional velocity:
* v = 22,000 km/s
Answer:
The recessional velocity of a galaxy at a distance of 1 billion light-years, with a Hubble constant of 22 km/s/Mly, is 22,000 km/s.
