## Meet the zeptosecond, the shortest unit of time ever measured

ABOVE – A particle of light, called a photon (yellow arrow), produces electron waves out of an electron cloud (grey) of a hydrogen molecule (red: nucleus). The result of those interactions is what’s called an interference pattern (violet-white). The interference pattern is slightly skewed to the right, allowing researchers to calculate the time for the photon to get from one atom to the next.

Scientists have measured the shortest unit of time ever: the time it takes a light particle to cross a hydrogen molecule.

That time, for the record, is 247 zeptoseconds. A zeptosecond is a trillionth of a billionth of a second, or a decimal point followed by 20 zeroes and a 1. Previously, researchers had dipped into the realm of zeptoseconds; in 2016, researchers reporting in the journal Nature Physics used lasers to measure time in increments down to 850 zeptoseconds. This accuracy is a huge leap from the 1999 Nobel Prize-winning work that first measured time in femtoseconds, which are millionths of a billionths of seconds.

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## Light Split Into Attoseconds, Captured in Image

You often hear and read about cameras capturing images at 100th of a second. Would it give you a jolt if you hear about a flashlight that captures light images of 80 attoseconds long.

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