Blink and you’ll definitely miss it.

Scientists have measured the shortest interval of time ever recorded, clocking how long it takes a particle of light to cross a single molecule of hydrogen.

The ultra-quick journey took 247 zeptoseconds, according to a team of German researchers, with a zeptosecond representing a trillionth of a billionth of a second. This is equivalent to the number 1 written behind a decimal point and 20 zeroes.

The findings are the culmination of global efforts to measure shorter and shorter time spans in physics, and they offer scientists a way to precisely measure atomic changes through what’s known as the photoelectric effect.