Question

In science it is often useful to estimate if a measurement is in the right ballpark by comparing it to a value you already know. Given that our Sun is about 8.5 kpc from the center of the Galaxy and about 2/3 of the way from the center to the edge of the Galaxy, which of the following is the best estimate of the radius of the Milky Way Galaxy?

Answer 1

As far as 2/3 of the way from the center to the edge of the Galaxy – i.e. 2/3 of the radius of the Milky Way Galaxy – equals to 8.5 kpc , then the radius itself equals to (8.5*3)/2 = 12.8 kpc.