The amount of time it takes a light particle to pass a hydrogen molecule was measured by a team of researchers to create the smallest unit of time ever. A trillionth of a billionth of a second is the unit of measurement known as a zeptosecond. That consists of a decimal point, 20 zeroes, and a one.
In 2016, scientists were able to measure time in 850 zeptosecond increments. According to researchers, the new degree of accuracy allowed for the measurement of 247 zeptoseconds. Compared to the femtosecond, which is millionths of a billionth of a second, that is a significant improvement in accuracy. In 1999, work on femtoseconds was awarded the Nobel Prize.
Zeptoseconds are used to measure how long it takes light to pass through a single hydrogen molecule, whereas femtoseconds are used to measure how long it takes chemical bonds to form and break. Richard Dorner, a physicist at Goethe University in Germany, and his colleagues employed x-rays from the PETRA III particle accelerator at Deutsch Elektronen-Synchrotron (DESY) in Hamburg.
The x-rays’ energy was calibrated such that just one photon—a particle of light—could dislodge two electrons from the hydrogen molecule. Using a device known as a Cold Target Recoil Ion Momentum Spectroscopy (COLTRIMS) reaction microscope, the team was able to quantify the interference pattern that was produced by the contact.
The device is a very sensitive particle detector that can capture atomic and molecular reactions that happen very quickly. The team calculated the time it took light to move through the molecule to be 247 zeptoseconds using the technique. In essence, the researchers managed to measure the speed of light inside a hydrogen molecule. According to Dorner, the team noticed for the first time that the electron shell and the molecule don’t respond to light uniformly across the board.
