Physicists used zeptoseconds to measure results of an experiment (Metro.co.uk)
Physicists used zeptoseconds to measure results of an experiment (Metro.co.uk)

A team of physicists have recorded the shortest possible measurement of time: the zeptosecond.

A zeptosecond is a trillionth of a billionth of a second. Or, to give it its numerical value: 0.000000000000000000001.

The scientists, from Goethe University in Germany were required to use the measurement to record how long it takes for a photon (a light particle) to travel across a hydrogen molecule. The answer is 247 zeptoseconds.

Technically, there are smaller measurements of time (the yoctosecond, anyone?) but scientists haven’t been able to measure them against anything yet.

In the case of the hydrogen molecule, the German physicists used a technique involve X-rays and powerful microscope to get their measurement. Essentially, a particle accelerator in Hamburg smashed the photons into the hydrogen molecules and a very high-tech microscope measured the result.

‘Since we knew the spatial orientation of the hydrogen molecule, we used the interference of the two electron waves to precisely calculate when the photon reached the first and when it reached the second hydrogen atom,’ explained Sven Grundmann whose doctoral dissertation formed the basis of the scientific article in Science.

‘And this is up to 247 zeptoseconds, depending on how far apart in the molecule the two atoms were from the perspective of light.’

An illustration showing a photon smashing into molecules to measure a zeptosecond
The photon (yellow, coming from the left) produces electron waves out of the electron cloud (grey) of the hydrogen molecule (red: nucleus), which interfere with each other (interference pattern: violet-white). The interference pattern is slightly skewed to the right, allowing the calculation of how long the photon required to get from one atom to the next. (Credit: Sven Grundmann, Goethe University Frankfurt)

So, if you want some particularly good pub quiz ammo, you could say that Usain Bolt’s world record 100m sprint took him just 19,190,000,000,000,000, 000,001 zeptoseconds.

Or the time it takes for the human heart to beat 60 to 100 times takes on average 60,000,000,000 000,000,000,001 zeptoseconds.