That’s 0.000000000000000001 seconds.
It’s impossible for the human mind to imagine just how short of a timeframe that is, so let me give you some comparisons.
12 attoseconds is the shortest measurable period of time.
In a single second, light can circle the Earth 7.5 times. In a single attosecond, light would barely manage to move from one end of a molecule to the other end.
If you could perceive the world in that speed, even light would appear frozen to you.
1 attosecond is to a second what the size of an atom is to the size of the entire Earth. Times 100.
If you were an immortal living in that timeframe, you would live out the entire age of the universe in the time it would take a normal person to blink.