If they can calculate weight, that means they should be able to calculate size. How far is it to the edge of the universe?
Supposedly the earth is weightless. But it is also said to weigh 6.585 sextillion tons (that's 10 to the 21st power). The sun has 333,000 times the mass of the earth. So if the Milky Way's mass is 1.5 trillion times the mass of the sun, the weight of the Milky Way should be something like 3.3 duodecillion tons (or 10 to the 39th power).
But my math could be wrong. To get the weight in pounds, multiply by 2,000.