English: These tiny micron sized pits store user data in Giga Bytes which is pretty fascinating to think about. These are so tiny that even a highly powerful Zeiss optical microscope can't detect them. Apparently, you can measure a density of these pits, and do some calculations to find the storage capacity of the CD disks at home. This specific image is taken by me, using an Atomic Force Microscope owned by the University of Michigan, as part of my training for this job. Atomic Force Microscopes or AFMs are uniquely powerful in the way that they can measure the z height of samples using a laser and PSD (photodetector) motion. These 2D scans can give you 3D information about the specimens, after a little post processing.