Storing data for longer than a few years is tricky enough with rapidly advancing technology, so what are you supposed to do if you need to store data for thousands or even millions of years? That's just the problem facing nuclear waste management companies, who need a way to warn future civilizations of hazardous sites that will withstand the test of time. Luckily a recent proposal may have the solution with a sapphire disk etched in platinum that could survive longer than humanity itself.

Communicating with future generations is tricky for any number of reasons. Aside from finding a medium that will remain intact over the years, there's no way to accurately predict how people of the future will read data, what language they'll use, what technology they'll have at their disposal, or if they'll even be human by then. But when the information being preserved has to do with radioactive waste that can still be dangerous thousands of years from now, it's even more crucial to leave a warning that can be easily interpreted centuries from now.

That's why ANDRA, a French nuclear waste management agency, created a disk made of industrial sapphire that could last millions of years, thanks to the gem's exceptional toughness and resistance to scratching. The prototype was made by taking two thin, 20-cm (7.9-in) wide disks, etching one side of one disk in platinum, and then molecularly fusing them together. One disk made this way costs €25,000 (about US$30,738) and could hold up to 40,000 miniature pages of text or images. Theoretically, the sapphire should preserve the etchings so they can be viewed by any future archaeologists using a microscope. Currently the prototype has been submerged in acid to test its resilience, and ANDRA is confident the results will show the disk could survive for 10 million years.

The sapphire disk is one of many ideas currently being explored by ANDRA, which started a project to bring together material scientists, archaeologists, anthropologists, and other specialists to explore ideas for warning future excavators about hazardous waste sites. Fortunately the team has plenty of time to form a definite solution, since the nuclear waste repositories operating now will most likely not be sealed until the 22nd century. Even with time on their side, the group still hopes to identify all possible solutions to the problem and then narrow them down by 2014 or 2015.

ANDRA's project and sapphire disk may be aimed at managing radioactive waste, but whatever idea it settles on could open the floodgates for preserving even more vital information for the far off future.

Source: Science