Scientists have a set a new record in accurate timekeeping, creating an atomic clock that won't lose or gain a second in 15 billion years — a time span greater than the estimated age of the Universe. The clock measures the oscillation of strontium atoms to create its "tick," and could one day become the standard for the world's official time — Coordinated Universal Time (UTC). Currently, UTC is set using atomic clocks that measure the vibrational frequency of the element caesium, although these are only accurate in the region of one second in hundreds of millions of years.
The strontium clock, developed by physicists from the National Institute of Standards and Technology (NIST) and the University of Colorado Boulder, measures the movement of strontium atoms pinned in a narrow column with powerful lasers. All atoms have naturally consistent vibrational frequency (for strontium its about 430 trillion times per second) and the measurement of these movements is used to create the clock's "tick."
The strontium clock, known as an optical lattice clock, has been in development for several years and previously broke timekeeping records in 2013. However, a series of tweaks outlined in the journal Nature Communications (these include shielding the clock from types of electromagnetic radiation) have made it three times more accurate again. The clock's so accurate, in fact, that raising it just two centimeters off the Earth's surface has a noticeable effect, with even this minuscule change in gravity picked up by the clock's "tick."
This phenomenon is not just a matter of bragging rights though ("my clock's so accurate it notices when you put a notebook under it"), but could also help scientists create incredibly accurate maps of the shape of the Earth. The effect of gravity on the passage of time was first predicted by Albert Einstein's theory of relativity. It means, among other things, that clocks tick at different speeds at different elevations. Scientists believe that they can harness this phenomenon, using a network of incredibly accurate clocks spread across the surface of the Earth to measure its shape — a concept given the fantastic name of "relativistic geodesy."
Currently though, not even the strontium clock is accurate enough to beat conventional methods of measuring the shape of the Earth (scientists suggest it would need to measure an elevational difference of just one centimeter to be useful). This means the clock's creators will just have to be satisfied with all the other beneficial effects of more accurate timekeeping, including improving navigation and positioning systems such as GPS and pushing the boundaries of quantum physics.
Comments
Legit cool.
Though I couldn’t help but think that one day we’ll probably figure out an even more accurate way of keeping time. Not to diminish this accomplishment, not at all.
I’m also wondering if it’s possible to make a clock that isn’t affected by gravitational forces, sort of like a standard time reference (which is what we want I think), seeing as all time is relative due to the varying gravitational forces present wherever a clock might be; not just on Earth, but say in space, or on another planet.
Say we do decide to colonize other worlds, I think that would be useful. You’d have the local planet’s time and you’d also have your Standard Galactic Time or whatever other name you’d want to call it.
But we’d also have to agree to stop with this DST nonsense, either keep it on, or turn it off once and for all.
Good post, keep ’em coming.
By ÐeadRunner on 04.22.15 6:27am
DST is stupid, agreed.
By Optimus-Prime on 04.22.15 6:53am
But time and gravity are linked to each other. The change in the passage of time wrt gravity is explained by Einstein’s theory of general relativity. Also what’s even more bizarre is that different clocks showing different times in different gravity are not wrong. Time actually passes differently at different altitudes.
By whiskeylover on 04.22.15 8:20am
Well any such standard reference would just have to be of specified elevation – much like we already do for lat-(or is it long-?)-itude, giving everything either in GMT or relative to it.
e.g. "It’s 1747 GMT at Earth sea level."
By Fordy on 04.22.15 12:48pm
Our sun will be dead long before this thing loses a second. Who’s going to be around to appreciate that?
By i'm on the verge on 04.22.15 7:01am
Well that’s a little depressing to think about… Of course we’ll either have moved on from the planet and possibly have evolved into something else or be extinct by then!
I feel like we can stop building more accurate clocks now.
By milkydj on 04.22.15 7:50am
I believe the true benefit is in GPS and other system that rely on incredibly accurate time calculation. The more accurate the tick, the more accurate the measurements those tools will be able to provide. Its not about the time loss over millions of years.
By Mackoy on 04.22.15 11:21am
Given that the whole universe is ~13B years old, it can probably outlive the universe (if you believe various theories that it collapses and re-expands) before it loses a second.
Pretty much peak accuracy there.
By verger1 on 04.23.15 3:38am
Can someone who understands how these things work explain something that’s puzzled me about these accuracy claims?
How do you assess the accuracy of a clock that is more accurate than all other clocks? Is the 1 second every 15 billion years simply the theoretical loss?
By ifbnBvyozBTkEdKfeDJd7kxF on 04.22.15 7:15am
Just a matter of math I reckon.
By Citizen85 on 04.22.15 7:44am
Im no expert but I always though it had something to do with the rate of decay. More stable particles can be observed for longer and have a better degree of accuracy. If im wrong, please correct me.
By Mackoy on 04.22.15 11:25am
Now if they focus on the calendars, we seem to gain a day every 4 years!
By drumdbeat on 04.22.15 8:20am
If the clock is sensitive enough to detect minute variations in elevation, then what is going to be the "official" elevation for UTC? And if it is sea level (or a certain number of meters above sea level) what happens if sea level rises in the coming decades?
By AndyMac55 on 04.22.15 10:40am
I’m assuming it depends on the clock’s calibration. This clock is calibrated for whatever elevation it’s at now. A clock built somewhere else will be calibrated for that elevation.
By Password Length Limits Suck on 04.22.15 11:54am
This entire article just makes me want to watch Interstellar again.
By Jowiso on 04.22.15 11:54am
That movie was soooo depressing, after it was over I just felt depressed.
The way they were able to visually present time as a dimension was very interesting.
By wonshikee on 04.22.15 12:53pm
Hell yeah! I love that movie _
I watched it about a month after reading ‘A briefer history of time’, and the whole time I was like "THIS IS ACTUALLY BASED UPON LEGIT SCIENCE!!!"
By Imrhien on 04.22.15 8:40pm
All atoms have naturally consistent vibrational frequency (for strontium its about 430 trillion times per second) and the measurement of these movements is used to create the clock’s "tick."
I have to say, more than anything else is how insane that number is. How does it vibrate so fast?
The world at the atomic level is so fascinating and mysterious.
By wonshikee on 04.22.15 12:37pm
You got that right. Even Einstein got stumped by the world at the atomic level.
By ben cruz on 04.23.15 4:40am
Yah but starting when
By crappypunk on 04.22.15 5:52pm