Let Your Fingers Do the Seeing

Humans can feel objects that are just nanometers thick, a new study says.  We can feel tiny details invisible to the naked eye, such as the grit of this high-end sandpaper.

Sandpaper. Colored scanning electron micrograph (SEM) of the surface of advanced sandpaper showing the regular pyramidal arrangement on its surface. Sandpaper is designed to smooth rough surfaces by taking off their upper layers, and this type consists of tiny raised pyramids which are highly durable and abrasive. Magnification: x15 at 6x7cm size.