On Wednesday, February 7, 2024, a story by journalist Tijana Nikolić, in which Dr. Aleksandar Bogojević, Director of the Institute of Physics Belgrade, talks about timekeeping, was broadcast on Dnevnik 1 of the Serbian Radio and Television.
Dr. Bogojević spoke about atomic clocks that used to be the standard in timekeeping, so while using them, the Institute had the most accurate time measurement in the region.
“Atomic clocks have to be cooled, but not with liquid nitrogen, which is relatively cheap, but with liquid helium in order to be accurate,” Dr. Bogojević said, explaining why they are no longer in use, but added that there are now new methods for timekeeping.
“The vibration rate of the excited state of levels in some atoms is measured with atomic clocks and this is taken as a standard. With this method, we have a billion times more precise definition of what one second is compared to mechanical watch timekeeping. However, now you look at the sky and some objects called pulsars, and from them, you can distinguish billionths of a second even more precisely,” says Dr. Bogojević.