Hydrogen Atom

phrenopolis.com

Cool website that visualizes a hydrogen atom, showing how much empty space makes up our universe.

The page is scaled so that the smallest thing on it, the electron, is one pixel. That makes the proton, this big ball right next to us, a thousand pixels across, and the distance between them is... yep, fifty million pixels

If your monitor displays 72 pixels to the inch, then that works out to eleven miles - making this possibly the biggest page you've ever seen.