Question

What is the formula for Hubble's constant?

Answer 1

The Hubble constant `H_0` is given by 'Recession velocity = `H_0` X Distance'. See explanation.

Explanation:

All galaxies appear to be receding from one another.

Galaxies' motion is described as motion of islands in our universe.

And the velocity of a galaxy is estimated by the Doppler Effect ( the light emitted by a source is shifted in wave length, by the motion of light source).

In respect of this motion, Edwin Powell Hubble (1889-1953) had discovered, in 1929, the linear correlation that is given in the answer.

As of now, `H_0` = 71 km/s/mega parsec and this leads to the estimate of age of our universe as 13.8 billion years, from the reciprocal `1/H_0`, after befitting unit conversions.