The Shortest Recorded Event Is Precisely 247 Zeptoseconds

Scientists have managed for the first time to record an event that lasts just 247 zeptoseconds, the shortest observed duration of any event in human history. We didn’t even know what zeptoseconds were.

It’s often said that life is short, and time is fast. Both those things are true in a relative sense. But when you talk about the time it takes for a single particle of light to pass through a hydrogen molecule – well, simply put, there’s never been anything faster or shorter.

In fact, the time it takes light to pass through a hydrogen molecule is now officially both the fastest and shortest event ever recorded – and it takes exactly 247 zeptoseconds.

Now, it’s a good bet that most of you have never heard of a zeptosecond. And that’s perfectly fine. Not many people outside theoretical and particle physicists have heard of it.

To bring you up to speed, a zeptosecond is one trillionth of a billionth of a second. Yep, that’s right. Digitally expressed, it looks like this: 0.000 000 000 000 00 000 001.

So, getting back to the single light particle passing through a hydrogen molecule, a group of scientists has managed to actually record this event for the first time ever. Their findings have been published in the peer-reviewed journal Science. And there are no prizes for guessing that the authors of the study were physicists.

They were, in fact, physicists from the Goethe University in Frankfurt, Germany and their observations now allow scientists to witness the interactions of light and matter with an entirely new level of detail.

And here is the science bit. It gets a little complicated but stay with me. The physicists shined particles of X-ray light on hydrogen molecules in a gas. As each light particle, or photon, crossed a Hydrogen molecule it forced an electron out of first one hydrogen atom and then the other.

As electrons can exhibit wavelike behaviour, the two expulsion events stirred up electron waves that spread out and merged — similar to the ripples formed by a stone skipped twice over a pond.

The overlapping crests and troughs of those waves created an interference pattern, which the researchers observed using an instrument called a reaction microscope, which is a high-resolution “microscope” for the investigation of the dynamics of atomic, molecular and nuclear reactions.

If the electron waves had formed simultaneously, the interference pattern would have been symmetric around the centre of the Hydrogen molecule.

But because one electron wave formed slightly before the other and had more time to spread out, the pattern shifted toward the second wave, says study co-author Sven Grundmann, a Goethe University physicist.

This shift let the researchers calculate the 247-zeptosecond time delay between the emission of the two electron waves. That matched the team’s expectations based on the speed of light and known diameter of a hydrogen molecule.

Past experiments have observed particle interactions as short as attoseconds, which are 1,000 longer than zeptoseconds.

Five Fun Science Facts:

1. There are as many zeptoseconds (zs) in one second as there are seconds in 2,500 times the age of the universe, which is about 13.8 billion years old.
2. The only units of time shorter than a zeptosecond are a yoctosecond and Planck time.
3. A yoctosecond (ys) is a septillionth of a second.
4. Planck time is a theoretical concept in quantum physics, named after the German physicist Max Planck. Planck time (tP) is the unit of time in the system of natural units known as Planck units.
5. A Planck time unit is the time required for light to travel a distance of one Planck length in a vacuum, which is a time interval of approximately 5.39 × 10 −44 s.