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Calling a clock the most accurate ever may sound like hyperbole, but physicists at the National Institute of Standards and Technology in Boulder, Colorado have built a pair of devices that can ...
An accelerometer measures proper acceleration, which is the acceleration it experiences relative to freefall and is the acceleration felt by people and objects. [2] Put another way, at any point in spacetime the equivalence principle guarantees the existence of a local inertial frame, and an accelerometer measures the acceleration relative to that frame. [4]
Here a single reference frame of yardsticks and synchronized clocks define map position x and map time t respectively, the traveling object's clocks define proper time τ, and the "d" preceding a coordinate means infinitesimal change. These relationships allow one to tackle various problems of "anyspeed engineering", albeit only from the ...
An accelerograph can be referred to as a strong-motion instrument or seismograph, or simply an earthquake accelerometer.They are usually constructed as a self-contained box, which previously included a paper or film recorder [1] (an analogue instrument) but now they often record directly on digital media and then the data is transmitted via the Internet.
An inertial navigation system (INS; also inertial guidance system, inertial instrument) is a navigation device that uses motion sensors (accelerometers), rotation sensors and a computer to continuously calculate by dead reckoning the position, the orientation, and the velocity (direction and speed of movement) of a moving object without the ...
That is, clocks at higher altitude tick faster than clocks on Earth's surface. This effect has been confirmed in many tests of general relativity, such as the Pound–Rebka experiment and Gravity Probe A. In the Hafele–Keating experiment, there was a slight increase in gravitational potential due to altitude that tended to speed the clocks ...
The most accurate pendulum clocks were controlled electrically. [166] The Shortt–Synchronome clock, an electrical driven pendulum clock designed in 1921, was the first clock to be a more accurate timekeeper than the Earth itself. [167] A succession of innovations and discoveries led to the invention of the modern quartz timer.
The first clock had an accuracy of 10 −11, and the last clock had an accuracy of 10 −15. The clocks were the first to use a caesium fountain , which was introduced by Jerrod Zacharias , and laser cooling of atoms, which was demonstrated by Dave Wineland and his colleagues in 1978.