Friday, November 7, 2008

Masa untuk berubah?

A group of Tokyo University scholars has created an experimental atomic clock that is believed to be far more accurate than current ones that gain or lose just a second over tens of millions of years, it has been learned.

The so-called optical lattice clock is regarded as a promising technology for the next-generation of ultra-high-accuracy clocks.

The research group, led by Associate Prof. Hidetoshi Katori, published details of the experiment in the Oct 27 edition of science magazine Nature Physics.

The atomic clocks that set world standard time define the duration of a second in terms of the frequency of transition of the cesium-133 atom.

The optical lattice clock, meanwhile, confines atoms in minute optical lattices created by lasers irradiating from six directions – back and forth, right and left, and up and down.

As the atoms that emit light are trapped in the lattices, the measured frequency is far more accurate than that provided by current cesium atomic clocks.

The research group succeeded in measuring time intervals as minuscule as one-2,000 trillionth of a second by fixing 100,000 strontium atoms, which oscillate at a higher frequency than cesium, in the optical lattices.

Currently, the optical lattice clock’s accuracy is about twice to 10 times that of the atomic clock.

However, if the method is improved by increasing the number of atoms used or in other ways, it would be possible, in theory, to make an ultra-accurate clock that would gain or lose no more than a second over 10 billion years, according to the research team.

The universe itself is thought to be between 13.5 billion and 14 billion years old.

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