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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.



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RE: .
By masher2 (blog) on 8/1/2006 2:52:24 PM , Rating: 2
> "That's right, I forgot, global warming isn't real"

Global warming is real. What's not real is the belief that its an impending crisis caused by humanity.

It's not clear how much of the warming, if any, is due to human activity, nor how long the warming will continue, nor whether or not the overall effect will be beneficial or harmful. The earth warms and cools constantly...its been much hotter and much cooler than now in the past, and will be so in the future. With or without our help.



RE: .
By ceefka on 8/2/2006 7:23:16 AM , Rating: 2
Recently global dimming is also becoming an issue.

This definately has to do with burning fuels. It means less of the sunlight is getting through because particles stay in the atmosphere, in the cloulds. They act like a giant filter.

While oil reserves may be bigger than they used to be, that isn't a good thing, really. I'd be happier if they were smaller, so that we'd all be forced to use it wisely and think about alternative, read more enviromental friendly, energy.


RE: .
By masher2 (blog) on 8/2/2006 7:53:25 AM , Rating: 2
> "Recently global dimming is also becoming an issue. "

Oops, the most recent research has shown just the opposite-- that the "dimming trend" first observed has since reversed:

quote:
Newly available surface observations from 1990 to the present, primarily from the Northern Hemisphere, show that the dimming did not persist into the 1990s. Instead, a widespread brightening has been observed since the late 1980s...


http://www.sciencemag.org/cgi/content/abstract/308...

> "I'd be happier if [oil reserves] were smaller...

As would most rabid eco-guerillas. However, cheap abundant energy is the single most critical factor affecting standard of living. I realize many environmentalists would be happier with us living in a stone-age culture (or so they think, at least), but the rest of us prefer progress forward, not backwards.


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