Hi, the number of earths it would take to equal the distance of the milky way's diameter would be a number hard to comprehend. The milky way's diameter is supposed to be around 100,000 light years across; if you stop and think that light travels at 186,000 miles per second, or around 5.8 trillion miles per year; and then multiply that by 100,000 and then divide that by 8,000, the diameter of the earth, the number I came up with, give or take a few, you'd have to have 73,321,200,000,000 earths. Either way you add it all up, that's a lot of earths put side to side. I'm no math major for sure, but played around on the calculator and input what I know about my prior astronomy experience and info I had at hand. The distance between earth and the sun is roughly 93,000,000, or 93 million miles and that's just a trip to the mail box compared to going end to end with the milky way galaxy. The distance between most objects in space is hard to comprehend as we tend to think in much smaller numbers. Hope this helps, mark savage, Lumberton, NC