A group of scientists has measured the shortest unit of time ever with a measurement of the amount of time it takes a light particle to cross a hydrogen molecule. The measurement is called a zeptosecond and is a trillionth of a billionth of a second. That is a decimal point followed by 20 zeros and a one.
Researchers in 2016 were able to measure time in increments down to 850 zeptoseconds. Researchers say that the new level of accuracy was able to measure 247 zeptoseconds. That is a massive increase in accuracy compared to the femtosecond, which is millionths of a billionth of a second. Work on femtoseconds won a Nobel Prize in 1999.
The time it takes for chemical bonds to break and form is measured in femtoseconds, but zeptoseconds is the measurement used to measure light as it travels across a single hydrogen molecule. Physicist Richard Dorner of Goethe University in Germany and colleagues used x-rays from the PETRA III at Deutsch Elektronen-Synchrotron (DESY), which is a particle accelerator in Hamburg.
The energy of the x-rays was set to allow a single photon, or particle of light, to knock two electrons out of the hydrogen molecule. The interaction created a wave pattern called an interference pattern that the team could measure using a tool called a Cold Target Recoil Ion Momentum Spectroscopy (COLTRIMS) reaction microscope.
The tool is a very sensitive particle detector that can record extremely fast atomic and molecular reactions. Using the tool, the team determined that 247 zeptoseconds is the time it took light to travel in the molecule. The team essentially captured the speed of light inside of the hydrogen molecule. Dorner said that the team observed for the first time that the electron shell and the molecule doesn’t react to light everywhere at the same time.