What is the most accurate clock in the world?

Question

What is the most accurate clock or timepiece in the world and what makes it so accurate?

Answer 1

The most accurate clock in the world, as of January 2007, is the atomic clock CS2 at the Physikalisch-Technische Bundesanstalt (PTB), in Braunschweig, Germany. It has an error of plus or minus 1.1 nanoseconds. (Their web site say they do better than this, but that's only after the clock time is "corrected".)

The United States Naval Observatory (USNO) in Washington D.C., was #2 for January; their clock error was plus or minus 1.5 nanoseconds.

The U.S. National Institute of Standards and Technology (NIST), in Boulder Colorado, was #7 in the world, errors of plus or minus 4.8 nanoseconds.

But ... every month, this changes. Perhaps the NIST clock is the most accurate this month.

Atomic cesium clocks are accurate because cesium has a very precise vibration frequency. Also, these clocks are made and operated very carefully, so that anything that might disturb them is kept away.

Every month, clocks from 56 locations around the world are compared and an average is calculated. This average is the official time. Unfortuantly, this official time is known only after the month is over! But scientists can also figure out the error in each clock, so they can say (a month late), that when the USNO clock said January 21, 4:15:00, it was really that time plus 5 nanoseconds (as an example).

The stuff that Marine52 says, about the NIST-F1 clock, is true if you average the clock errors over a long time. But if you take just single readings of the time, they were off by plus or minus 4.8 nanoseconds during January, about 68% of the time. He forgot to include the link, I put it in the list below.

Answer 2

NIST-F1, the nation's primary time and frequency standard, is a cesium fountain atomic clock developed at the NIST laboratories in Boulder, Colorado. NIST-F1 contributes to the international group of atomic clocks that define Coordinated Universal Time (UTC), the official world time. Because NIST-F1 is among the most accurate clocks in the world, it makes UTC more accurate than ever before.

The uncertainty of NIST-F1 is continually improving. In 2000 the uncertainty was about 1 x 10-15, but as of the summer of 2005, the uncertainty has been reduced to about 5 x 10-16, which means it would neither gain nor lose a second in more than 60 million years! The graph below shows how NIST-F1 compares to previous atomic clocks built by NIST. It is now approximately ten times more accurate than NIST-7, a cesium beam atomic clock that served as the United State's primary time and frequency standard from 1993-1999.

Answer 3

Atomic Clocks
http://www.units.muohio.edu/dragonfly/time/accurate.htmlx

Answer 4

Any anologue watch or clock that has stopped. It's 100% correct twice a day!

Answer 5

the most acurate clock in the world is the one given by satellite.

Answer 6

The one on the dashboard of my 1987 Ford Escort.

It's built Ford tough...........