How big and how far away would the moon be if earth was the size of Jupiter?
The basic numbers are:

Radius of Earth 6370km
Radius of Moon 1740km
Earth-moon distance 384000km and
Radius of Jupiter 71500km

So the scale factor is 71500/6370 = 11.22
The radius of the moon scaled is 1740×11.22 = 19500 km, and its distance becomes 384000×11.22 = 4310000 km
For comparison, Neptune has a radius of 24600 km and a distance from Jupiter of that is always more than 3700000000 km
The size of the &quot;moon&quot; is comparable to Neptune, but the distance from Jupiter to Neptune is nearly 1000 times greater than the distance to the &quot;moon&quot;.