Huzzah, a full-sized, themed puzzle! I tend to post mostly midi-size puzzles on here, but I doubt there's really a good home elsewhere for this particular puzzle. As the title indicates, you will be well served by any prior knowledge of physics, science, and mathematics, but you don't need  any such expertise to solve the puzzle. It would just really help because, in addition to the theme answers, I peppered the fill with plenty of science-related entries and clues. (In particular, [spoiler alert] you may want to look back to this post about my puzzle on 7xwords for more info about one entry in this puzzle.) You may also notice one blemish of asymmetry here: there's an extra black square just to the left of where 66-Across begins. I didn't need  to add this to make the grid fillable at all, but I did need it to make the entries in that corner more reasonable and science-related. I'm hoping that, like me, you either won't care/notice at all, or you'll thin...