March 10, 2012
Nuclear Clock Keeps Time With The Universe
As time passes, new technology evolves in order to keep time. Soon the trusty atomic clock may be replaced by a nuclear clock, which keeps time to 1/20th of a second in 14 billion years.
In early time, the sun or grains of sand in an hourglass kept time. Over the years technology allowed for clocks you could wind, watches with quartz oscillators, and more recently the atomic clock.
The atomic clock uses an electronic transition frequency to keep time. Considered quite accurate, atomic clocks are used for GPS devices and have become standard for time distribution services. The accuracy isn't being called into question, but scientists at the University of New South Wales in Sydney, Australia have proposed a clock that can tell time with even more precision.
The proposed nuclear clock can tell time for 14 billion years, the age of the universe, without gaining or losing 1/20th of a second.
"This is nearly 100 times more accurate than the best atomic clocks we have now," said researcher and Scientia Professor Victor Flambaum, in a statement. Professor Flambaum is Head of the Theoretical Physics in the University of New South Wales School of Physics.
A paper discussing the proposed nuclear clock is due to be published in the journal Physical Review Letters. Contributions from U.S. researchers at the Georgia Institute of Technology and the University of Nevada are included in the paper. Professor Flambaum and colleague Dr. Vladimir Dzuba, also from UNSW, report the proposed single-ion clock will be accurate to 19 decimal places.
If the proposed nuclear clock is accepted, the new standard for keeping time will be lasers that orient electrons in a specific way to use the orbiting neutron as a pendulum. An atomic clock works by using orbiting electrons of an atom as the clock pendulum. The neutron is held tightly to the nucleus making its oscillation rate almost completely unaffected by any external perturbations. With an atomic clock, electrons are more loosely bound.
To date, the atomic clock at the U.K.'s National Physical Laboratory (NPL) is said to have the best long-term accuracy. Work from UNSW's School of Physics could call the accuracy of even the most accurate atomic clock into question.
"With these clocks currently pushing up against significant accuracy limitations, a next-generation system is desired to explore the realms of extreme measurement precision and further diversified applications unreachable by atomic clocks," said Professor Flambaum.
On the Net:
- University of New South Wales
- Physical Review Letters
- Georgia Institute of Technology
- University of Nevada