Nov 25 (NHK) - Japanese scientists plan an experiment to gauge the effect of gravity on time.
They will place ultra-precise clocks on the ground level and the 450-meter-high observation deck of the Tokyo Skytree tower to determine the time difference.
Albert Einstein's theory of general relativity says the weaker gravity becomes, the faster time flows. Accordingly, a clock at the height of 450 meters will tick minutely faster than one on the ground level, as gravity is weaker up there.
In 2015, a team led by Professor Hidetoshi Katori at the University of Tokyo developed "optical lattice clocks," which they say are 1,000 times more accurate than the cesium atomic clock that's used to define one second.
The team says the optical lattice clocks are so accurate they make it possible to detect a time difference caused by a one-centimeter gap in height.
The team has already measured a difference of four-10 billionths of one second per 3 days in central Tokyo and a town just outside, because of the altitude gap between the 2 locations.
Katori says that someday ordinary people will become familiar with the idea that the speed of time is deferent from place to place.
