Eternal Clocks?

There are laser and atomic clocks in special laboratory environments that are accurate to one second in 300 million years! Yet their lifetimes are typically less than 30 years. Some wristwatches run longer! There are mechanical clocks in development that could last about 10,000 years! But they would need periodic winding. Why do the laser and atomic clocks have such short lifetimes? How might one build a mechanical clock that would survive so long?

Answer

The laser clocks and the atomic clocks must maintain a vacuum within a reasonably small range of parameters to function accurately. The temperature and pressure must be maintained within a certain tolerance because temperature fluctuations or pressure fluctuations could bring about inaccuracies. Even the outgassing of atoms and molecules from the container walls can create severe problems for some designs. Certainly, improvements will be made to ensure longer lifetimes and more robust timepieces. But maintaining vacuums, low temperatures, and so on, for decades and centuries will be constant problems in these sophisticated systems.

Whether a 10,000-year (or even a 1,000-year!) mechanical clock will ever exist and can stand the test of time and environment is doubtful. A group of engineers and futurists are presently developing such a clock containing a stack of rotating metal rings connected to a torsion pendulum. Periodic winding will be required, perhaps once a year or so.

No special environment is needed, although the assumption seems to be that a standard atmosphere with limited pollutant content is a reasonable expectation. We do know from a variety of scientific research projects that the oxygen concentration in the atmosphere has been very nearly constant at 21 percent for millions of years, so the rusting rate of the exposed metal can be predicted. But we do not know what future chemistry will bring. Even a local environmental disaster such as excess acidity in the air from volcanic eruptions, a chemical explosion, or careless disposal could shorten the life span of the clock dramatically.