And you thought the old way of measuring stuff was good enough...

So have you ever heard of the Michelson interferometer? Well this is the technology of splitting a light wave in half and then recombining the two beams at a later point and measuring the interference created at the detector. Remember light waves can be combined to strengthen the signal at the detector or cancel one another to show differences in the distance the two light beams traveled. Because of this inference pattern, measurements can be made down to half of a wavelength of the light being used. So visible light in the range of 400 to 700 nanometers can be used to measure differences of 200 to 350 nanometers. This may sound pretty good but scientists have found a way to make it even more accurate. They did it using super cooled Cesium atoms and an interferometer.

"Just as waves of light can sometimes act like particles called photons, atoms can be coaxed into showing off their inner waves. In this condition, an atom can exist in two or more places at once, called a superposition." So this wave of atoms can be split and then recombined to measure differences of thousandths of nanometers. This is incredible because the accuracy of measurements just jumped from 100's of nanometers to thousandths of nanometers(a picometer). Anyway take a look at this article Extreme Measures in the February 16, 2008 issue of Science News to read more about this. Take a look. I know you will be impressed.