Question

How does the Hubble law relate to the big bang theory?

Answer 1

Hint: Both laws are about the expansion of the universe. The big bang theory is about a big explosion-like event that gave birth to the universe as we know it. The Hubble’s law gives the relation between the separation of the two objects and their velocities of expansion.

Complete answer:
To account for the observed red shift in the wavelength emitted by the light of the stars surrounding us, various theories have been propounded. One major theory is the big bang theory which describes that around 13.9 billion years ago an explosion caused the creation of the universe from the matter that was condensed in very small volume.
The Hubble’s law says that the velocity of expansion of two bodies (celestial) is directly proportional to the distance of the two bodies. This means that if we are observing a star or a galaxy from our planet then, we can say that the farther that star is from us, the faster it is moving away from us. Hubble’s law was discovered before the big bang theory was propounded. By using the Doppler’s law, we are able to determine the velocity of the star (source) by measuring the shift in wavelength of the light observed. By knowing this, we know the rate of expansion of the universe. Big bang theory is an attempt to explain why this expansion is occurring.

Note:
Red shift is a term given for the change in wavelength of the light to longer wavelengths as the source of the light moves farther from the point of observation. Blue shift can be said to have occurred in case when the source moves closer to the observer.