If you must preserve messages for people in the far future to read, Blu-ray discs and USB sticks are no good. For real long-term storage, you want a DNA time capsule.
Just 1 gram of DNA is theoretically capable of holding 455 exabytes – enough for all the data held by Google, Facebook and every other major tech company, with room to spare. It’s also incredibly durable: DNA has been extracted and sequenced from 700,000-year-old horse bones. But conditions have to be right for it to last.
Research suggests that data in DNA form could last 2000 years if kept at a temperature of around 10 °C. The Global Seed Vault in the Arctic could preserve it for over 2 million years at a chilly -18 °C, offering truly long-term storage. Learn more here.