zeptosecond

A zeptosecond is the SI unit of time equal to 10^-21 seconds. The symbol for this unit is zs, and it uses the SI prefix zepto-, which denotes a factor of 10^-21. A zeptosecond is one sextillionth of a second.

Zeptoseconds belong to the ultrafast timescale and are far shorter than attoseconds, which are 10^-18 seconds. They arise in discussions of nuclear and subatomic dynamics, where processes at extremely small temporal intervals may occur. The measurement and manipulation of such brief intervals require highly specialized instrumentation and techniques beyond conventional ultrafast spectroscopy.

Generating and capturing light or events on the zeptosecond timescale is a focus of ongoing research. Proposed approaches include advanced high-harmonic generation schemes and next-generation light sources, such as X-ray free-electron lasers, combined with precision pump-probe methods. Experimental demonstrations of zeptosecond-scale control or measurement remain at the frontier and are technically demanding.

In use, the zeptosecond prefix provides a way to describe phenomena that occur on unimaginably short timescales. It appears mainly in theoretical discussions and experimental planning within physics, rather than in everyday timekeeping or common measurements.