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Friday, April 17, 2009

World's most accurate clock unveiled

Perfect timekeeping has taken a step closer to reality after scientists developed a clock that loses just a second every 300 million years.

By Richard Alleyne, Science Correspondent
Atomic clock: World's most accurate clock unveiled
Ultra-cold strontium atoms in an atomic clock Photo: PA

The researchers claim the new atomic clock is more than twice as accurate as timepieces currently used to regulate international time zones and satellite systems.

Like its predecessors, the strontium atomic clock at the University of Colorado, harnesses the natural – and extremely consistent – vibration of atoms to keep track of time.

But it makes the "pendulum effect" of atoms even more consistent by holding them in a laser beam and freezing them to almost minus 273 degrees – the temperature at which all matter stops resonating.

"An atom consists of a nucleus and some electrons that spin in clearly defined orbits around the nucleus," said Professor Jan Thomsen, a nuclear physicist at the University of Copenhagen, who has worked with the new experiments together with researchers at the University of Colorado.

"By using the focused laser light one can make the electron swing back and forth in a clearly defined way between these orbits, and it is that which forms the pendulum in the atomic clock".

Even though the increase in accuracy represents only a small fraction of a second, it has great potential in areas to do with the determination of great distances - for example, measuring the distance to distant galaxies in space.

Now the team want to go a step further.

"We dream of getting an atomic clock with perfect precision," said Prof Thomsen.