Now cut one of those slices 10 more times, and you've reached the limit of vision of the best optical microscopes. But now comes the big step. Take one of these strips and cut it 1,000 more times. Objects this small could never show up in a conventional microscope. Ordinary light is too crude a medium to carry such delicate information.
Light waves wash past atomic-scale features, like ocean waves rolling over seashells.
Electron microscopes, as the name suggests, work with electrons instead of light. Electrons move with a wavelength vastly smaller than that of visible light, so they can interact with correspondingly smaller objects. An electron microscope focuses a beam of electrons onto the object, which spews out its own electrons and X-rays. The microscope creates an image by reading the energy and distribution of these emissions. One kind of microscope, the scanning electron microscope, sweeps the beam over the surface of an object.