people tend to think in terms of largeness. Look at the size of the planet Jupiter. But what about smallness?
Eek. Sounds Heideggerian. Is that a word?
What if there are microcosms of undetected galaxies and solar systems out there the size of a single cell, or perhaps even as small as an atom? And what if the most advanced life in the universe inhabits one of these microscopic worlds? Then they could easily be flitting their miniature spacecraft around us all the time, even into and out of our nostrils and ears, completely unsensed or unseen observers...or manipulators. The same could be said for the other relativity of size...what if the entire universe as we perceive it is just a germ on somebody else's laboratory slide?...hmmmm?
There's a cool sf book you might find interesting if the genre sits well with you. It's by John Forward and titled Dragon's Egg. I think Star Trek: TNG plagiarized (or 'adapted') it in one episode.
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