John Ellis is a really smart person who studies stuff that's so tiny that you can't see it even with really good eyes or a big microscope. This stuff is so small that it's like the building blocks of everything in the world, like how legos are used to build bigger things.
John Ellis looks at these tiny building blocks and tries to figure out how they work and what they're made of. He's kind of like a puzzle solver, trying to figure out how all the pieces fit together. He also helps other people who study this kind of stuff so they can learn more about it too.
John Ellis knows a lot about how the world around us works, but there's still so much more to discover. That's why he keeps studying and trying to figure things out.