The recessional velocity of a galaxy at a distance of 180 mpc will be 70 km/sec
Hubble's law, which says simply that a galaxy's velocity (or as is sometimes plotted, its redshift) is directly proportional to its distance, also tells us something important about the state of the universe. If the universe is static and unchanging, there should be no correlation between distance and velocity.
Recessional velocity is the rate at which an extragalactic astronomical object recedes (becomes more distant) from an observer as a result of the expansion of the universe. It can be measured by observing the wavelength shifts of spectral lines emitted by the object, known as the object's cosmological redshift.
Recessional velocity = Hubble's constant * distance
= 70 km/sec/Mpc * 180 Mpc
= 70 km/sec
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