# How big and how far away would the moon be if earth was the size of Jupiter?

If the earth were the size of Jupiter, what would its 'moon' be in both relative size and distance? I did some quick figuring and think I roughly figured out that if placed at the position of the sun, Jupiter's moon would be Neptune in both relative size and current distance from the sun. That seems very distant and I'm questioning my calculations. The moon is 27% as large as the earth and is ~27,700 times the earth's diameter distant. Jupiter is ~87,000 miles in diameter. That would make it's moon ~23,500 miles in diameter and ~2.41 billion miles distant. Neptune comes relatively close to those results. It would be slightly larger than our moon (30,600 miles in diameter vs. 23,500) and slightly farther away (2.8 billion miles away vs 2.41) but still close for comparison purposes. That puts the moon relatively MUCH more distant from the earth than what I would have thought off the top of my head.

The basic numbers are: