Scientists build atomic clock accurate to one second in 300 billion years

"I am convinced that what we have now is the world's most accurate clock," says research leader Murray Barrett at the National University of Singapore in a press release.

It is an atomic clock based on the unusual element lutetium, whose electrons change energy levels rapidly and regularly and are barely affected by temperature or magnetic fields. The changes are measured with a laser, and the oscillations act as a kind of pendulum.

Friends of order may wonder how accurate the clock really is - the answer is a margin of error of one second in about 300 billion years.

The clock is intended to be used to measure gravitational changes on Earth and perhaps to redefine what a second actually is.