DailyTech - New Mercury-Ion Atomic Clock Accurate for 400 Million Years

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Science New Mercury-Ion Atomic Clock Accurate for 400 Million Years
Tuan Nguyen (Blog) - August 1, 2006 10:21 AM

68 comment(s) - last by masher2.. on Aug 3 at 12:37 PM

Redefining time

According to reports published in the Physical Review Letter, the National Institute of Standards Technology (NIST) published a paper indicating that it had discovered a new type of atomic clock based on mercury-ion. The report said that the new atomic clock is so accurate it's nearly 6 times more precise than the current cesium-based atomic clock.

The report said that the NIST currently operates a cesium-based atomic clock called the NIST-F1, which is accurate for roughly 70 million years. If operated continuously, the NIST-F1 would only be off by 1 second after 70 million years. The new mercury-ion atomic clock on the other hand will take 400 million years.

The new experimental clock measures the atomic resonance frequency of a mercury atom. The atom itself is electrically charged and kept in an extremely cold suspension. Using the new mercury-ion atomic clock, scientists at the NIST say that they will be able to conduct more precise experiments and further develop applications that rely on atomic-time accuracy such as GPS systems. Currently, the international standard that defines what one second is relies on cesium-based atomic clocks -- 9,192,631,770 radiation cycles of the change between two energy levels of a cesium atom. The NIST says that it will be five to ten years before we see mercury-ion clocks replace cesium ones.