To measure small time differences, you need a really small clock, and researchers in Germany have discovered the smallest known clock: a single hydrogen molecule. Using the movement of light along the length of this molecule, these scientists measured the smallest time interval ever: 247 zeptoseconds. You don't know what a "Zepto" is? Continue reading…
When a bit of light, called a photon, hits an atom with enough energy, it can kick the electron out of that atom and make it fly. If we set up this situation carefully in a laboratory, we can measure the electron shooting out of the atom and deduce when it got the big kick from the incident photon.
With more than one electron, you can turn this arrangement into a tiny, very fast clock. The photon hits one electron and then the other. By measuring the delay between outgoing electrons, we can measure the time it takes for the photon to travel from one electron to another within the molecule.
For years, scientists have been building various atomic devices to do just that, and they are finding ever smaller clocks. A team from Goethe University in Germany recently managed to achieve this with just a single hydrogen molecule: two protons that share two electrons.
Using an X-ray beam at Deutsches Elektron-Synchrotron (DESY), a particle accelerator in Hamburg, the team observed the slight temporal differences when the two electrons snap out of the molecule when the X-rays take them, as in the October issue of Science.
From there they could calculate the time it took for the X-ray photons to jump from one end of the molecule to the other. And this time difference was hardly anything: 247 zeptoseconds. A zeptosecond is a trillionth of a billionth of a second.
If you want that to be spelled out (and I know you do) it looks like this: 0.000000000000000000247 seconds.
It's a new world record for the shortest time interval ever recorded. Further work in this area will help us understand the detailed structures of molecules and their relationship to incident photons, which are used everywhere from chemistry to nuclear energy.