OUR most accurate clocks are probing a key tenet of Einstein’s theory of relativity: the idea that time isn’t absolute. Any violation of this principle could point us to a long-sought theory that would unite Einstein’s ideas with quantum mechanics.
Special relativity established that the laws of physics are the same for any two observers moving at a constant speed relative to each other, a symmetry called Lorentz invariance. One consequence is that they would observe each other’s clocks running at different rates. Each observer would regard themselves as stationary and see the other observer’s clock as ticking slowly – an effect called time dilation.
Einstein’s general relativity compounds the effect. It says that the clocks would run differently if they experience different gravitational forces.
For two decades, comparing atomic clocks aboard GPS satellites with those on Earth have helped test the effect – and always confirmed it. But since any deviation from relativity would be very subtle, we might need a more precise instrument to find it.
Most atomic clocks rely on the frequency of the microwave radiation emitted when electrons in caesium-133 atoms change energy states. Next-generation clocks that use strontium atoms have at least three times the precision, barely gaining or losing a second over 15 billion years.
Read more:
https://www.newscientist.com/article/mg23331184-900-atomic-clocks-make-best-measurement-yet-of-relativity-of-time/?utm_source=NSNS&utm_medium=ILC&utm_campaign=webpush&cmpid=ILC%257CNSNS%257C2016-GLOBAL-webpush-ATOMICCLOCKS
Δεν υπάρχουν σχόλια:
Δημοσίευση σχολίου