From: whatis.com
Part of the Electronics glossary:
An atomic clock
is the most accurate type of timepiece in the world, designed to measure time
according to vibrations within atoms. NIST-F1, the United States' standard
atomic clock, is said to be so accurate that it would neither gain nor lose a
second in over 30 million years. Atomic clocks are used to coordinate systems
that require extreme precision, such as Global Positioning System ( GPS )
navigation and the Internet. A group of atomic clocks located in a number of
places throughout the world are used in conjunction to establish Coordinated
Universal Time ( UTC
Like a regular
clock, an atomic clock keeps time according to oscillation , which is a
periodic variation or movement between two entities or between two states of a
single entity, created by changes in energy. In a pendulum-driven clock, for
example, the oscillation is the back and forth movement of the pendulum (the oscillator
). Such a clock keeps time according to the frequency of the pendulum's swing,
which will be more or less accurate, depending on a number of variables. The
precision of an atomic clock, on the other hand, depends upon the fact that an
atom, caused to oscillate, will always vibrate at the same frequency.
In 1945, Isidor
Rabi, a physics professor at Columbia University, proposed that atomic
vibrations could be used to keep time, based on something he'd developed called
atomic beam magnetic resonance . Four years later, the National Bureau
of Standards (now the National Institute of Standards and Technology ) had
developed an atomic clock that used the vibrations of ammonia molecules.
NIST-F1, the United States' current standard, uses cesium atoms; it and a
similar atomic clock standard in Paris are the most accurate timepieces ever
made.
The first
commercial cesium-based atomic clocks were manufactured by the National
Company, a Massachusetts-based firm; Frequency Electronics, FTS, and Hewlett
Packard ( HP ) are among the companies producing them today. Atomic clocks have
never been widely used in consumer products because they are typically large
and use too much power. Recently, however, NIST developed an atomic clockwork
that overcomes these problems. About the size of a grain of rice and accurate
to within one second in 126 years, the new mechanism could soon be manufactured
on computer chips and used in consumer market handheld devices, such as radios,
GPS systems, and cellular telephones.
============================================
In addition to this blog, I have authored the premiere book on Netiquette, "Netiquette IQ - A Comprehensive Guide to Improve, Enhance and Add Power to Your Email". You can view my profile, reviews of the book and content excerpts at:
www.amazon.com/author/paulbabicki
If you would like to listen to experts in all aspects of Netiquette and communication, try my radio show on BlogtalkRadio and an online newsletter via paper.li.I have established Netiquette discussion groups with Linkedin and Yahoo. I am also a member of the International Business Etiquette and Protocol Group and Minding Manners among others. I regularly consult for the Gerson Lehrman Group, a worldwide network of subject matter experts and I have been contributing to the blogs Everything Email and emailmonday . My work has appeared in numerous publications and I have presented to groups such as The Breakfast Club of NJ Rider University and PSG of Mercer County New Jersey.
In addition to this blog, I have authored the premiere book on Netiquette, "Netiquette IQ - A Comprehensive Guide to Improve, Enhance and Add Power to Your Email". You can view my profile, reviews of the book and content excerpts at:
www.amazon.com/author/paulbabicki
If you would like to listen to experts in all aspects of Netiquette and communication, try my radio show on BlogtalkRadio and an online newsletter via paper.li.I have established Netiquette discussion groups with Linkedin and Yahoo. I am also a member of the International Business Etiquette and Protocol Group and Minding Manners among others. I regularly consult for the Gerson Lehrman Group, a worldwide network of subject matter experts and I have been contributing to the blogs Everything Email and emailmonday . My work has appeared in numerous publications and I have presented to groups such as The Breakfast Club of NJ Rider University and PSG of Mercer County New Jersey.
==========================================
No comments:
Post a Comment