In a lab in England, they built a battery out of diamond — and carbon-14. It would still hold half its power in the year 7700. Its makers built something they will never see finish. A message in a bottle, sent forward in time. It says: we were here, and we were thinking of you.
Carbon-14 decays so slowly that a diamond built around it can drip power for thousands of years — a battery that treats centuries like minutes. Nobody alive will see it run dry. Some things are not made to be used. They are made to be found.