Everyday, it seems, consumer products store more information; MP3 players, smart cards, and digital cameras now hold hundreds of megabytes of data, many times the capacity of the first computer hard drives. It can make you wonder; is our demand for data storage insatiable? (Possibly.) And if so, is there any limit to the data we will be able to store in a reasonable space? (Definitely.)
Currently, data is stored in microscopic patterns recorded on magnetic disks, on optical media such as CDs and DVDs, and in the circuitry of memory chips. The finest patterns are typically microns (millionths of a meter) in size, smaller than a red blood cell, which means that we can store gigabytes (about 1,000,000,000 bytes) per square centimeter of storage material. The marks that represent each bit of data, however, are comprised of many millions of atoms. We could dramatically increase data storage by decreasing the number of atoms that represent each data bit.
If we were to store data in patterns of individual atoms, we could pack several terabytes (thousands of gigabytes) into a square centimeter. At these data densities, the entire collection of the Library of Congress would fit into a one square centimeter of storage media -- that's more than 17 million books, 4 million maps, and 50 million manuscripts.
That's the ultimate limit of data storage, so long as we write data on flat, two-dimensional surfaces. If we developed three-dimensional, atomic-scale data storage (picture something like a cube of sugar, with each crystal representing a bit of data) the limits of data storage soar to nearly unimaginable densities. A speck of 3D atomic storage material the size of the period at the end of this sentence could store every word ever spoken by every human being in the history of the world, with plenty of room to spare.