If the spectroscopic interpretation of the motion of the galaxies is considered true, the calculations of the dimensions of the universe will have to be modified; for the theory of the expanding universe invalidates the calculations of the mass and radius of curvature of the universe based on the assumption that the universe is steady and that the Einstein’s model is the true representation of the universe.

The new calculations can be made only if the velocities of recessions of the galaxies are known.

The astronomers made the measurements of the velocities and the distances of the receding galaxies. To their great astonishment, they found their velocities to be tremendously great. It was noticed that, generally speaking, the galaxies which are nearer to the earth have a velocity of about 100 miles a second, while those which are nearly 250 million light-years away, are receding with a tremendous velocity of 25,000 miles per second. On the basis of observations, Edwin Hubble has established a law of the velocities of receding galaxies according to which “out to 6 million light-years the velocity of galaxy is proportional to its distance.”^{[1]} This means that the velocities of receding galaxies are proportional to their distances.

The value of the increase in the velocity of the galaxies per unit of distance, according to Eddington, is 528 kilometers per second per megaparsecond (1 megaparsecond being equal to 3.26 million light years).^{[2]} This is called the ‘constant of nebular recession’.

Abbe Lemaitre, the Belgian cosmologist, had shown on theoretical basis that for an expanding universe which had originated from an Einstein world of radius Ro the value of Vo, the constant of nebular recession, is given by the equation -

Where C is the velocity of light.

Eddington promptly set out to verify the theoretical expansion predicated by Lemaitre with the observed expansion announced by the American astronomers, and was able to deduce some important consequences.^{[3]}

Eddington substituted the value of V_{o} which was available from the observations, in Lemaitre’s equation (eq.no.(v) above), and thus determined the value of R_{o}, the initial radius of curvature of the universe. As a result of this he found:^{[4]}

R_{o}= 1,068,000,000 light years.

Eddington also determined the value of M, the mass of the universe, which he assumed to remain constant during the expansion, by using the Einstein’s equation (our eq.no. (i)).

According to Dr. George Gamow, on the basis of the theory of expanding universe, the radius of curvature of the universe is 5 million light years.^{[5]}