\[d=\frac{v}{H_0}\]
Variables
ddistance to the galaxy (Mpc)
vrecession velocity (km/s)
H0Hubble constant (km/s·Mpc)
Description
What is this formula?
Hubble's law relates the recession velocity of distant galaxies to their distance from the observer. It describes the expansion of the universe and is one of the foundations of modern cosmology.
When to use it
Use this formula when the recession velocity of a galaxy is known and its approximate cosmological distance needs to be estimated.
Example
A galaxy is observed moving away at:
v=7000 km/s
Assume:
H0=70 km/s·Mpc
Formula:
d=v/H0
Substitution:
d=7000/70
Result:
d=100 Mpc
The galaxy is approximately 100 megaparsecs away.
Applications
- Cosmological distance estimation
- Expansion of the universe studies
- Redshift analysis
- Observational cosmology
- Extragalactic astronomy