Wired: Ultra-Precise Quantum-Logic Clock

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bystander
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Wired: Ultra-Precise Quantum-Logic Clock

Post by bystander » Sat Feb 06, 2010 4:17 pm

Ultra-Precise Quantum-Logic Clock Puts Old Atomic Clock to Shame
Wired Science - 2010 Feb 05
Scientists have built a clock which is 100,000 times more precise than the existing international standard.

The quantum-logic clock, which detects the energy state of a single aluminum ion, keeps time to within a second every 3.7 billion years. The new timekeeper could one day improve GPS or detect the slowing of time predicted by Einstein’s theory of general relativity.

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neufer
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Re: Wired: Ultra-Precise Quantum-Logic Clock

Post by neufer » Sat Feb 06, 2010 5:09 pm

[url=http://www.wired.com/wiredscience/2010/02/quantum-logic-atomic-clock/]Ultra-Precise Quantum-Logic Clock Puts Old Atomic Clock to Shame[/url] wrote: Scientists have built a clock which is 100,000 times more precise than the existing international standard.

The quantum-logic clock, which detects the energy state of a single ALUMinum ion, keeps time to within a second every 3.7 billion years. The new timekeeper could one day improve GPS or detect the slowing of time predicted by Einstein’s theory of general relativity.
http://en.wikipedia.org/wiki/Washington_meridian wrote:
The Washington meridian was one of four prime meridians of the United States.
The four which have been specified are:
  • 1. through the Capitol
    2. through the White House
    3. through the old Naval Observatory
    4. through the new Naval Observatory.
Many western states have borders that are [whole degree number] meridians of "longitude west of Washington",
that is, west of the legal 1850 meridian through the Old Naval Observatory.

In 1793, Secretary of State Thomas Jefferson surveyed and marked with a wooden post the southwest vertex of L'Enfant's triangle, establishing the second Washington meridian, the one through the President's house. The wooden post was replaced by the Jefferson Pier in 1804, while Jefferson was President of the United States. After removal and replacement several times, it was permanently replaced in 1889 by a 2-foot square, 2-foot tall, granite pier, now 390 feet WNW of the center of the Washington Monument. Its longitude is 77°2'11.56"W.
http://www.greatdreams.com/washmnmt.htm wrote: .
<<The Washington Monument *ALUMinum apex*
representing a small pyramid, on top of the 3300 pound capstone.>>
Image
  • . _Finnegans Wake_ page 423

    . The *ALUM* that winters on his top is the stale
    . of the staun that will soar when he stambles till
    . that hag of the coombe rapes the pad off his lock.
http://www.usatoday.com/life/enter/books/fc/codebook.htm wrote:
. _The Code Book_ by Simon Singh
. The Evolution of Secret Writing
.
<<Secret communication achieved by hiding the existence of a message
is known as steganography, derived from the Greek words steganos,
meaning *coVERED*, and graphein, meaning 'to write'. In the fifteenth
century, the Italian scientist Giovanni Porta described how to conceal
a message within a hard-boiled EGG by making an ink from a mixture
of one ounce of *ALUM* and a pint of vinegar, and then using it to
write on the shell. The solution penetrates the porous shell,
and leaves a message on the surface of the hardened EGG albumen,
which can be read only when the shell is removed.>>
Art Neuendorffer

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neufer
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Aluminium-26

Post by neufer » Sat Feb 06, 2010 5:29 pm

http://en.wikipedia.org/wiki/Aluminium-26 wrote:
<<Aluminium-26, 26Al, is a radioactive isotope of the chemical element aluminium, decaying by either of the modes beta-plus or electron capture, both resulting in the stable nuclide Magnesium-26. The half life of 26Al, 717,000 years, is far to short for any except an infinitesimal amount of the primordial atoms of the isotope to survive to current time, but small amounts of the nuclide are produced by collisions of Argon atoms by cosmic ray protons. Aluminium-26 also emits gamma rays and X-rays. The gamma emission at 1809 keV was the first observed gamma emission from the galactic center. The observation was made by the HEAO-3 satellite in 1984.>>
Image
The picture shows the obtained line profile of the 1809 keV line obtained with the SPI instrument on-board INTEGRAL. This 1809 keV line results from radio-active decay of 26 Al. This element is a key-tracer of star formation. The line is also moderately broadened which could reflect the kinematics of the 26 Al ejecta. However, the width of 3.3 +/- 1.3 keV could also be consistent (at the 2 sigma level) with an unbroadened line. Credits: Juergen Knoedlseder, CESR
Art Neuendorffer