If a galaxy is 1,000 Mpc away, how fast isit recending?

To determine the speed at which a galaxy is receding, we need to use the concept of redshift. Redshift is a phenomenon where light from distant galaxies appears shifted toward longer wavelengths, which indicates that the galaxy is moving away from us. The redshift value, denoted by z, is a measure of this shift.

To calculate the recession velocity, we can use Hubble's law, which states that the recession velocity (v) of a galaxy is directly proportional to its distance (d). Mathematically, it can be expressed as:

v = H0 * d

Where H0 is the Hubble constant, which represents the rate of the universe's expansion. Its current value is estimated to be around 70 km/s/Mpc.

Now, given that the galaxy is 1,000 Mpc away, we can calculate the recession velocity:

v = 70 km/s/Mpc * 1,000 Mpc

v = 70,000 km/s

Therefore, the galaxy is receding from us at a velocity of 70,000 km/s.