Particle physics, in short, is a hugely expensive enterprise—but it is a productive one. Today the particle count is well over 150, with a further 100 or so suspected, but unfortunately, in the words of Richard Feynman, "it is very difficult to understand the relationships of all these particles, and what nature wants them for, or what the connections are from one to another."
Inevitably each time we manage to unlock a box, we find that there is another locked box inside. Some people think there are particles called tachyons, which can travel faster than the speed of light. Others long to find gravitons—the seat of gravity. At what point we reach the irreducible bottom is not easy to say.
Carl Sagan in Cosmos raised the possibility that if you traveled downward into an electron, you might find that it contained a universe of its own, recalling all those science fiction stories of the fifties. "Within it, organized into the local equivalent of galaxies and smaller structures, are an immense number of other, much tinier elementary particles, which are themselves universes at the next level and so on forever—an infinite downward regression, universes within universes, endlessly. And upward as well."
For most of us it is a world that surpasses understanding. To read even an elementary guide to particle physics nowadays you must now find your way through lexical thickets such as this: