5D discs, by comparison, store information within their interior using tiny physical structures known as “nanogratings.” Much like those bumpy lines in the CDs, these change how light is reflected, but instead of doing so in just two “dimensions,” the reflected light encodes five — hence the name. The changes to the light can be read to obtain pieces of information about the nanograting’s orientation, the strength of the light it refracts, and its location in space on the x, y, and z axes. These extra dimensions are why 5D discs can store data so densely compared to regular optical discs. A Blu-ray disc can hold up to 128GBs of data (the same as the biggest iPhone), while a 5D disc of the same size could store nearly 3,000 times that: 360 terabytes of information.
