[boringg]

I thought you were being glib but no: "An attosecond is so short that that the number of them in one second is the same as the number of seconds that have elapsed since the universe came into existence, 13.8 billion years ago. On a more relatable scale, we can imagine a fash of light being sent from one end of a room to the opposite wall – this takes ten billion attoseconds."

That's truly amazing that we can measure at that detail. Mind blowing actually.