## New US Atomic Clock Goes Live 127

PaisteUser (810863) writes with news about a new, hyper-accurate atomic clock unveiled by the National Institute of Standards and Technology.

*"A new atomic clock, so accurate it will lose or gain only one second every 300 million years, was unveiled Thursday by the National Institute of Standards and Technology, a branch of the U.S. Department of Commerce. The NIST-F2 had been in development for about a decade and is three times more accurate than the F1, which has been in use since 1999. The institute will continue operating both clocks for now at its campus in Boulder, Colorado."*
## Re:so the new clock is 3x as accurate as the old o (Score:4, Informative)

NIST has vastly more accurate clocks - so I don't see what the big deal is.

http://www.nist.gov/pml/div688... [nist.gov]

## Re:Mod parent up (Score:4, Informative)

No, the weight of a kilogram is completely arbitrary. They are trying to fix it to something but right now it is just a weight.

A atomic clock works by counting the vibrations in an atom. The atomic clock fails when it miscounts the vibration of an atom, causing the error. The new clock is so good at counting that errors rarely occur.

## gravitational time dialation (Score:5, Informative)

I met a guy that used to work at NIST that mentioned that their clocks are so sensitive, they can tell what floor the atomic clocks are on because of of the slightly different gravitational potential each clock experiences. I wonder what kind of resolution the can resolve. Can a very massive bolder throw off the clock a little? ..perhaps one day we will have to keep better track of the local gravitational potential well. It's possible to measure the gravitational constant with simple apparatus at home. Using two massive bodies in a torsion pendulum arrangement, you can estimate "big G" --
http://www.owlnet.rice.edu/~do... [rice.edu]

Here is an wikipedia article that mentions the phenomena with atomic clocks: http://en.wikipedia.org/wiki/G... [wikipedia.org]

## Re:so the new clock is 3x as accurate as the old o (Score:3, Informative)

The higher-accuracy clocks arewhich is a necessary basis for Standards Compliance. As I understand it, the F3 clock (from the article) is a "Cesium-fountain" atomic clock and is therefore suitable for use in standards-based calculations. The clock(s) referenced in that article, on the other hand, are Mercury and Aluminum based and therefore cannot be referenced according to SI standards.. The SI governing body would have to change their standard for the other clocks to be considered, but given how many things are based on the Standard, modifying it is a non-trivial exercise...

notbased onCesium,-AC