Hubble's Law Formula

Hubble's Law Definition

The universe, until the beginning of the 20th century, had been a domain of mystery and speculation. Among such revolutionary findings that took place during the time was the discovery that the universe is expanding. That simple understanding has now been termed Hubble's Law, through which the human understanding of the universe got recalibrated and prepared a platform for cosmology in its modern sense.

The Origin of Hubble's Law

It all started with Edwin Hubble, an American astronomer whose observations in the 1920s changed forever how humanity had generally perceived the universe until then. Till Hubble's time, it was believed that the universe was stationary and unchanging. Yet when Hubble studied remote galaxies, a shockingly different discovery came his way: these galaxies were moving away from us.

In 1929, Hubble published a paper in which he proposed a fundamental relationship between a galaxy's distance from Earth and its velocity. Today we call that relationship Hubble's Law.

Formula of Hubble's Law

The formula for Hubble's law gives a relation between recessional velocity and the proper distance of the galaxy measured in megaparsecs.

Hubble's Law is given in a rather simple formula:

where:

• v is the recession velocity of a galaxy away from us-usually measured in km/second

• Ho is Hubble's constant showing the expansion rate of the Universe-measured in km/second/Mpc

• d represents the distance of the galaxy from us, measured in megaparsecs, Mpc.

Conclusion

Hubble's Law is one of the cornerstones of modern cosmology. With this, Edwin Hubble gave a new look toward the cosmos showing that the universe is expanding. Our measurements continue to refine as we go deeper into the mysteries of the universe, but Hubble's Law will forever remind us of just what scientific discovery and the expanding frontier of human knowledge are capable of.