Preview copies aliens! Literally. Here is a screenshot:

The text selected on the pdf was copied (Cmd+C) and pasted (Cmd+V) from Preview to TextEdit. What did I get? A bunch of aliens.
I'm guessing this is an encoding issue. Is there a way to change encoding in Preview or something? Is there a way I can check what encoiding it is using and then choose the appropiate on TextEdit? Here is the text, just so you can see the squares for yourselves (No aliens, apparently that error character only appears on native OSX apps and not browsers).

(I must admit OSX's error character is pretty amusing).