I did it!
I found my way back!
The trick is to figure out your current exhibit, then find the PRIMARY article for the exhibit (the intro), and then backtrack through whichever door the primary aritcle is pointing to... and do that over... and over.... and over....
And then eventually the game glitches, you fall into the deep darkness between stars (and exhibits), knowledge rushes past your ears, and you slam into the firm reassuring woodwork of the lobby.