Atomic beams shoot straighter via cascading silicon peashooters

To a non-physicist, an "atomic beam collimator" may sound like a phaser firing mystical particles. That might not be the worst metaphor to introduce a technology that researchers have now miniaturized, making it more likely ...

In mice, feeding time influences the liver's biological clock

The timing of food intake is a major factor driving the rhythmic expression of most genes in the mouse liver, researchers report April 16th in the journal Cell Reports. The findings demonstrate that body-wide signals driven ...

New super-accurate optical atomic clocks pass critical test

Researchers have measured an optical clock's ticking with record-breaking accuracy while also showing the clock can be operated with unprecedented consistency. These achievements represent a significant step toward demonstrating ...

Understanding circadian rhythms in algae and fungi

Fungi, algae, and cyanobacteria might not complain about jet lag. But like humans, their physiologies adhere to a roughly 24-hour cycle of behavioral patterns in the absence of external cues. Organisms that experience recurring ...

Testing the symmetry of space-time by means of atomic clocks

In his Special Theory of Relativity, Einstein formulated the hypothesis according to which the speed of light is always the same, no matter what the conditions are. It may, however, be possible that—according to theoretical ...

'Doomsday Clock' stays at two mins to midnight

How close is human civilization to destroying the planet? The symbolic Doomsday Clock is still two minutes to midnight, as close as it has ever been, said the Bulletin of the Atomic Scientists on Thursday.

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Clock

A clock is an instrument used to indicate, keep, and co-ordinate time. The word clock is derived ultimately (via Dutch, Northern French, and Medieval Latin) from the Celtic words clagan and clocca meaning "bell". A silent instrument missing such a mechanism has traditionally been known as a timepiece. In general usage today a "clock" refers to any device for measuring and displaying the time. Watches and other timepieces that can be carried on one's person are often distinguished from clocks.

The clock is one of the oldest human inventions, meeting the need to consistently measure intervals of time shorter than the natural units: the day; the lunar month; and the year. Devices operating on several different physical processes have been used over the millennia, culminating in the clocks of today.

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