This is the biggest web page that I could load with Firefox (IE? errr... nope. Opera? errr... sorry).

Its 599999999px by 599999999px which on my PC is just under 70 km sq. I put a scale map of the solar system in it - pluto is about 68km that way -------->

Anything bigger than that and the scrollbars disappear.
Initially I thought I'd make this a kind of puzzle... not give directions to the planets and see if anyone could find them by scrolling about - a lost in space kind of thing.

Forget it. Space is big. If you get lost in it,
you stay lost.

At this scale, Alpha Centauri is about 4,658,000,000 km away

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The trouble with the speed of light, is that it's just too slow.