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