A nanometer is about the distance a beard hair grows in the time it takes for a man to raise the razor to his face.
Does that sound impressive? Well actually a nanometer is one billionth of a meter, so it’s pretty miniscule. It’s less a matter of how fast the average beard grows as it is a matter of how small the amount it grows is. To put in perspective, the space between atoms in a molecule is around 0.15 nanometers, and a DNA double helix is about 2 nanometers in width.
So the hair growth is really not impressively fast. Still, as you likely know, hair is ALWAYS growing. Another way of putting it in perspective is comparing it to the size of a marble vs the size of the earth. A nanometer is to a meter as a marble is to the entire earth.
On the subject of nanotechnology, a few years ago a man named Dustin W. Carr created a “nano guitar,” about the size of a red blood cell. The guitar can play actual notes just like its human sized counterpart, only these notes are so high (17 octaves, to be exact) and the guitar is so small that the notes can’t be heard by human ears.