There are some interesting technologies in the pipeline for truly long-term data storage. Synthetic diamond is one option (light-sensitive, so perhaps suscepti

There are some interesting technologies in the pipeline for truly long-term data storage. Synthetic diamond is one option (light-sensitive, so perhaps susceptible to cosmic-ray degradation over time): https://theconversation.com/turning-diamonds-defects-into-long-term-3-d-data-storage-67685 https://theconversation.com/turning-diamonds-defects-into-lo... Another is microetching, i.e. ion-beam insertion of foreign atoms into crystalline materials, such as diamond or nickel, although the data density is lower than the above approach, it seems a lot less sensitive (i.e. light should have less effect): https://en.wikipedia.org/wiki/HD-Rosetta https://en.wikipedia.org/wiki/HD-Rosetta