A zettasecond represents 10^21 seconds, which translates to roughly 31.7 trillion years. Because this time span is more than two thousand times the current estimated age of the universe, the unit has no practical application in engineering or daily measurement. It appears almost exclusively in theoretical physics and cosmology to describe the extreme long-term decay of subatomic particles or the ultimate fate of the universe.
Heard on the job
If proton decay actually happens, we're looking at a half-life measured in zettaseconds or more.
Insider tip
When you see zettaseconds in a paper, the author is usually talking about deep cosmological time or theoretical particle decay rates, not observable phenomena.