"Measuring the effect of altitude on the passage of time" is now possible thanks to the PHARAO project, according to Didier Massonnet of the French CNES. Launched to the International Space Station, the project aims to test Einstein's theory of general relativity with unprecedented precision.
Since 1915, it has been known that time is relative, slowing down near massive objects. The PHARAO atomic clock, along with a hydrogen maser, will measure time with such accuracy that it will only deviate by one second every 300 million years.
This project faced many technological difficulties, including miniaturizing the atomic clock for space and creating a precise microwave link for reliable time transmission to Earth. Nine terminals worldwide will compare PHARAO's time with their own atomic clocks.
The analysis of differences will determine if the results align with the predictions of relativity. If not, it could open new doors in physics, potentially reconciling general relativity and quantum physics, two currently incompatible theories.
This could advance the search for a unified theory of physics, explaining both the universe and the quantum realm. The success of this mission could revolutionize our understanding of time and the fundamental laws governing the universe.