How Large is a Nanometer?
A nanometer is quite small, a billionth of a meter. It is 20 times wider than the diameter of a hydrogen atom. In terms of the electromagnetic spectrum, 1 nanometer is about the wavelength of soft x-rays. Hard x-rays and gamma rays have a shorter wavelength. The width of a DNA double-helix, the molecule that carries our genetic code, is about 2 nanometers. As the wavelength of light is 400-700 nanometers, science did not possess microscopes capable of probing the 1-nanometer scale until the invention and refinement of the electron microscope. Electron microscopes use electrons rather than photons (light) to take images. Today’s best electron microscopes have a resolution of just 0.05 nanometers, the diameter of a hydrogen atom. To get the length of a nanometer in perspective, pretend you were shrunk in size about 1.5 billion times, so your height become 1 nanometer. A human would be about 1.5 million km tall, from our new perspective. This is about 120 Earth diameters, or three times l
