A few days ago, a news story appeared about the possible redefinition of the second. The BBC reported that scientists have invented a clock that loses just one second in 300 million years.
This new atomic clock is called the optical lattice clock. Its accuracy compares to the loss of one second every 100 million years by the caesium atom clock which is used for the current definition of a second. Given that the metre is defined as the distance that light travels in 1/299 792 458 seconds, a redefinition of the second will also change the definition of the metre.
Given the accuracy of the caesium atomic clock, we may ask why we need a more accurate definition of a second and what relevance has this to our daily lives. The BBC news report answers this as follows: “Many technologies such as telecommunications, satellite navigation and the stock markets rely on ever-better time measurements.”
This demonstrates that SI, the modern metric system, continues to evolve to meet the world’s ever-increasing demands for more accurate measurements. It is a measurement system that is fundamental to all measurements, both old and new.
The BBC report can be found at:
This news story has also appeared in UK newspapers, which can be found at the following links: