[ceejayoz]

For scale, Io is almost the same distance from Jupiter as the Moon is from Earth - about 400,000 kilometers.

That's about 0.3% the distance of Earth to the Sun.

For a good sense of how enormous these differences are, try the video "Riding Light" - https://vimeo.com/117815404 - Jupiter shows up at the 43:10 mark (Earth's at 8:17, for size comparison).