Word: cesium
(lookup in dictionary)
(lookup stats)
Dates: all
Sort By: most recent first
(reverse)
There is an official U.S. time, determined concurrently by the National Institute of Standards and Technology and the U.S. Naval Observatory. Both operate atomic clocks, which are capable of calculating the exact time within an infinitesimally small degree through a process that uses microwaves to manipulate cesium atoms. These clocks are publicly available, both at time.gov and over radio airwaves. GPS systems also carry on-board, constantly updated atomic clocks. (See the top iPhone applications...
...could truly appreciate the global slowdown until the invention of the atomic clock, which uses the oscillation frequencies of atoms such as cesium, hydrogen or rubidium to mark the passage of time. According to Andrew Novick, an engineer with the time and frequency division of the National Institute of Standards and Technology (NIST), there exist three types of atomic clocks: primary standard clocks, which are state-of-the-art instruments owned by only a handful of nations, such as Germany, Britain and the U.S. (there's one at NIST); smaller, rack-mounted commercially available versions that can cost as much...
...would be a fantasy. These clocks are so precise that they literally redefined time: Once tied to the mean solar day, the official measure of a second was changed in 1967 to refer to the duration of more than nine billion periods of radiation between two levels of the cesium 133 atom...
...decades after he officially retired from Harvard, the University felt it was the right time for Higgins Professor of Physics emeritus Norman F. Ramsey, the man who co-developed cesium and atomic clocks, to be honored at yesterday’s Commencement exercises with an honorary degree...
...environment. Furthermore, even during normal operation, power plants emit radioactive particles, including gases such as krypton, xenon, tritium, and argon, all of which can cause genetic diseases and gene mutations, not to mention iodine-131 (which causes thyroid cancer), strontium-90 (which causes leukemia and bone cancer), and cesium-137 (which causes muscle cancer). Then, of course, there is plutonium-239, which is so toxic that just one-millionth of a gram is carcinogenic. The United States has over 100 nuclear reactors, each of which produce about 200 kilograms of plutonium-239 per year. The bomb dropped on Nagasaki used...