The most accurate timepieces in use today are atomic clocks, commonly employed to keep time for Internet and satellite communications and various astronomical purposes. Their operation is based on naturally occurring frequencies of atoms responding to radiation. This works pretty well, providing accuracy to about 1 × 10~(-13) second, or a tenth of a trillionth of a second. Apparently, some people are just never satisfied, however, including researchers at UCLA's Henry Samueli School of Engineering and Applied Science. Last May, they demonstrated an optical clock that can track time with precision to 270 quintillionths of a second; a quintillionth being 1 × 10~(-18), or 0.000000000000000001. This is known as an attosecond. For reference, one attosecond is to one second as one second is to about 31.71 billion years.
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