From medieval times to the present, philosophers have wondered how many angels could dance on the point of a pin.
The solution, assuming one believes in visible angels, can be found in the modern science of nanotechnology. Thanks to electron microscopes and tools that can manipulate individual atoms, some of the world's smallest components are now routinely examined.
The prefix nano stands for one-billionth, and one-billionth of just about any single thing is way too small for the human eye to see. Even one-billionth of an elephant would be so small, you'd need that super microscope to inspect it. It might be a cute little creature, though.
But not to trivialize the miracle of nanotechnology: it is quite useful if you're designing the layout of a computer chip or studying human DNA. In fact, there's so much nanotechnology work being done in physics, medicine, chemistry, and engineering that scientists are worried about a nanobubble in which anything you can put a nano in front of is getting funded, whether there's merit to the research or not.
Here's an example of how deeply we've dipped into this teeny, tiny world. Physicists at the University of California at Berkeley are working with things called nanotubes. They're one-atom-thick sheets of graphite, 10,000 times thinner than a human hair. These nanotubes have been converted into microscopic-sized filaments to create the world's smallest radio, one that picks up actual station transmissions. The first song heard on nanoradio was a 1970s ditty called "Layla," by Derek and the Dominos.
This weeny radio is 100 billion times smaller than the first big, clunky commercial radios of the early 20th century.
The research team leader sees the potential for nanoradio probes throughout the bloodstream, or tiny nanoradios placed almost invisibly inside the human ear. You'd have to be careful not to scratch your ear, of course.
Nanotelevision will probably be next. Then future generations, if they zoom their nanocameras in really close, might finally see just how many angels can dance on the point of a pin.