Is this used as an idiom like "it's a small world," e.g. when you find out someone you just met went to the same school as your old neighbour or something, or has someone just been considering our place in the universe / they're lamenting that they don't feel there's anything left for them to see on this planet or something?
For the idiom - I'd say then "Jaki ten świat jest mały!" (How small this world is!)
So maybe it's closer to the second thing, I guess...