On: Grace Hopper on nanoseconds

[gnosis]

Then there's the attosecond[1], during which time light can only travel the length of three hydrogen atoms, and is the shortest measured period of time.

These[2] other time intervals are also interesting.

[1] - https://en.wikipedia.org/wiki/Attosecond

[2] - https://en.wikipedia.org/wiki/Orders_of_magnitude_(time)