Never before have researchers been able to measure such a short time span – 10 ^ -21 seconds.
It was world news when the Egyptian chemist Ahmed Zewail managed to measure the speed at which molecules change shape. These processes take place on the order of femtoseconds. An almost incomprehensible period of time in which a femtosecond takes only 0.000000000000001 seconds.
Zeptosecond
There is no question that there are even shorter periods of time. But just look at measuring them. Researchers of the Goethe University in Frankfurt have now succeeded. They have studied a process that takes place on the order of zeptoseconds.
And with that, researchers immediately have the shortest time span ever measured. A zeptosecond is also a significant step shorter than the femtosecond. Where the one after the decimal point at the femtosecond has to tolerate fourteen zeros, that is 20 at the zeptosecond.
Photos
But which process is so exceptionally short? The researchers put it in the magazine Science from the cloths. It is about the journey of a photon (a light particle) through a hydrogen molecule. That journey takes 247 zeptoseconds.
Don’t calculate, but measure
That in itself is nothing new, says researcher Sven Grundmann. “The average bond length (ie the distance between the two hydrogen atoms that make up a hydrogen molecule, ed.) Was already known and the same applies to the speed of light. So in principle you can calculate quite easily that it takes a photon 247 zeptoseconds to travel through this molecule. ” What makes the research so special is that researchers did not calculate it, but measured it. “That has never been done before, because there was no suitable clock for it.”
Stopwatch
And with that we also immediately tackle the biggest challenge of the research. “You first have to have a stopwatch, or in other words, come up with a way to measure such short periods of time,” says Grundmann. And so Grundmann and colleagues have done that. They sent a photon on a hydrogen molecule. This first encountered the first hydrogen atom in the hydrogen molecule and stripped it of its electron, and then did the same with the second hydrogen atom before leaving the molecule. The removal of an electron is accompanied by electron waves, which originate first in the first atom and later in the second. “Compare it to a flat stone hitting the water twice and creating two wave patterns,” explains Grundmann. Where these wave patterns are in principle symmetrical, because of this disturbance – prompted by the fact that the stone hits the water at two different moments – they become asymmetrical. “You can deduce from that asymmetry how much time has passed between the first and second touch of the water.” And something similar happens during the meeting between the photon and the hydrogen molecule. “The photon is actually the rock that first hits the first hydrogen atom and later the second. The outgoing electron waves create a distorted pattern and that asymmetry allows us to calculate how long it takes the photon to travel through the hydrogen molecule. ”
Quantum
Measuring zeptoseconds is not directly useful in everyday life, but that is different for the quantum world, or the world of the smallest particles. “Some processes in that world go very fast. And to be able to study them against their duration, you have to be able to measure short periods of time. ”
For now, the shortest measured time span is in the order of zeptoseconds, but Grundmann has no doubts that this will change over time. “I think there are people who will come up with smart ways to measure even shorter time frames. In atomic and molecular physics we have now reached our limit, I think: we have seen how the fastest object (light, ed.) Travels the shortest possible distance. But we may be surprised in the future. ”
–
Keep amazed ✨
Receive the most beautiful space photos and interesting popular science articles every Friday. Get the free Scientias Magazine together with 50,000 others.
