Question

How big is our galaxy and how fast is the universe expanding?

Answer 1

Our galaxy is 100-180 k ly wide, with 2 k ly bulge at the center. Our universe is expanding at the rate of 71 km/sec/mega parsec.

Explanation:

Here, ly = light year unit of distance = 62900 X( Earth- Sun distance), nearly, and k = 1000..

The greater unit of distance, mega parsec = million parsec, where parsec = 206265 X ( Earth-Sun distance)

The average Earth-Sun distance is the unit AU = 149597871 km.

It is scientifically surmised that our universe, expanding at the rate of Hubble Constant `H_0` = 71 km/s/mega parsec. has attained radial expansion to 13.8 billion light years, in 13.8 billion years.