Researchers in the US have shown that time passes faster the higher up you are by bringing relativity back to Earth.
Albert Einstein's theory of relativity shows that gravity and veolicty impact on time. Previously, experiments have confirmed this by comparing atomic clocks on the Earth's surface with ones placed in high-altitude jets and rockets.
Reporting in the journal Science, Dr James Chin-Wen Chou and colleagues from the National Institute of Standards and Technology (NIST) in the United States, have used the latest generation of atomic clocks to measure changes in time at a more down-to-Earth scale.
The researcher's first experiment involved lifting one clock above the other allowing them to measure the change in the Earth's gravitational pull over distances of less than a metre.
Their results confirmed time moves quicker, and hence a person ages faster, when they stand a couple of steps higher on a staircase.
The difference isn't much, about 25 billionths of a second over a 79 year life time, but it will have more practical applications in areas like global positioning systems and geophysics.
After examing the effect of altitude Chou's team then compared speed.
They did this by moving the clocks relative to each other by velocities of just a few metres per second, and again showed that the clocks kept slightly different times.
The key to both experiments is the quantum logic atomic clock, which uses the oscillation of a single aluminium ion to maintain precise timiing. The atom vibrates between two energy levels over a million billion times per second allowing the clocks accuracy down to a second in 3.7 billion years.
Setting a new standard
Professor Ken Baldwin, a physicist with the Australian National University says, these clocks will become the new standard, being 100 times more accurate than today's atomic clocks.
Baldwin says the study's findings reveal some interesting side effects caused by everyday life.
"It means when you run for the bus, you can now measure the fact that you are a little bit younger than if you stood still," he says.
Baldwin says accurate timing is important because we rely on global positioning systems to determine our exact location on the Earth, as well as making very accurate geodesy calculations.
"That's important for tidal measurements and detecting shifts in the Earth," he says. "It makes a difference to research in geology, the movement of water on the Earth's surface, changes in the icecaps, all sorts of activities that relate to understanding the position of massive objects on the planet's surface".