Keeping time precisely for five billion years

 

“Strontium atoms floating in the center of this photo are the heart of the world's most precise clock. The clock is so exact that it can detect tiny shifts in the flow of time itself.” Photo via NPR, courtesy of the Ye group and Brad Baxley/JILA.

From NPR:

This new clock can keep perfect time for 5 billion years.

"It's about the whole, entire age of the earth," says Jun Ye, the scientist here at JILA who built this clock. "Our aim is that we'll have a clock that, during the entire age of the universe, would not have lost a second."

But this new clock has run into a big problem: This thing we call time doesn't tick at the same rate everywhere in the universe. Or even on our planet.

"It's about the whole, entire age of the earth," says Jun Ye, the scientist here at JILA who built this clock. "Our aim is that we'll have a clock that, during the entire age of the universe, would not have lost a second."

Right now, on the top of Mount Everest, time is passing just a little bit faster than it is in Death Valley. That's because speed at which time passes depends on the strength of gravity. Einstein himself discovered this dependence as part of his theory of relativity, and it is a very real effect.

The relative nature of time isn't just something seen in the extreme. If you take a clock off the floor, and hang it on the wall, Ye says, "the time will speed up by about one part in 10¹⁶."

That is a sliver of a second. But this isn't some effect of gravity on the clock's machinery. Time itself is flowing more quickly on the wall than on the floor. These differences didn't really matter until now. But this new clock is so sensitive, little changes in height throw it way off. Lift it just a couple of centimeters, Ye says, "and you will start to see that difference."

This new clock can sense the pace of time speeding up as it moves inch by inch away from the earth's core.

Read and listen to Geoff Brumfiel’s whole story, New Clock May End Time As We Know It, at NPR.

Hat tip to Mike the Mad Biologist.

Comments

[El Jefe]

Yes it's timey-wimey, but is it wibbly-wobbly? That could turn out to be a design flaw if not....

[Mark]

I'm afraid the story is a little exaggerated. If what Ye says, I figure that moving the clock off the floor and hanging it on a wall will change the time by about a second in 300 million years. That means the total error from the origin of the Earth would be in the neighborhood of 10 to 15 seconds. I would say that means the relative nature of time really is seen only in the extreme, at least if you're talking about changes due to small changes in gravitational field. And I would say that the headline for the story is just plain silly.