Einstein’s theory of general relativity holds that a massive body like Earth curves space-time. It caused time to slow as you approach the object. A person on top of a mountain ages a tiny bit faster than someone at sea level.
US scientists have confirmed the theory at the smallest scale ever. It demonstrated that clocks tick at different rates when separated by fractions of a millimeter.
National Institute of Standards and Technology and University of Colorado Boulder scientists discovered their new clock was “by far” the most precise ever built. This could pave the way for new discoveries in quantum mechanics. It is the rulebook for the subatomic world.
The research has been published in the prestigious journal Nature. It described the engineering advances. It enabled them to build a device 50 times more precise than today’s best atomic clocks.
It wasn’t until the invention of atomic clocks. It keeps time by detecting the transition between two energy states inside an atom exposed to a particular frequency. The scientists could prove Albert Einstein’s 1915 theory.
Early experiments included the Gravity Probe A of 1976. It involved a spacecraft 6,000 miles above Earth’s surface. It showed that an onboard clock was faster than an equivalent on Earth by one second every 73 years.
The clocks have become more and more precise, since then. It is able to detect the effects of relativity.
NIST scientists observed time moving at different rates when their clock was moved 33 centimetres higher, in 2010.
Theory of everything
The key breakthrough was working with webs of light. It is known as optical lattices. It is to trap atoms in orderly arrangements. This is to stop the atoms from falling because of gravity or otherwise moving. It resulted in a loss of accuracy.
Inside the new clock are 100,000 strontium atoms. It is layered on top of each other like a stack of pancakes. It is in total about a millimetre high.
The clock is precise. The scientists divided the stack into two. It can detect differences in time in the top and bottom halves. Clocks essentially act as sensors, at this level of accuracy.