Why a Group of Physicists Watched a Clock Tick For 14 Years Straight (wired.com)

An anonymous reader writes: If you drop your phone today and it falls to the ground, you can be fairly certain that if it slips from your grip again tomorrow (butterfingers!), it won't suddenly soar into the sky. That's thanks to one of the basic ideas in Einstein's theory of general relativity, which posits that the laws of physics don't change over space and time. But to actually know that for a fact, you'd have to perform the same task over and over again, in as many locations as possible, and watch closely for any change in outcome. That's why, as Sophia Chen reports, a group of physicists has spent the past 14 years -- or 450 million seconds -- watching clocks tick.

Their results would have made Einstein heave a sigh of relief. The physicists were observing the 12 atomic clocks to see whether their subatomic particles' behavior changed over those 14 years -- but it was completely consistent, even as the clocks moved with the Earth around the sun. Now, these findings don't necessarily mean that the laws of physics are absolutely not changing across time and space. They only definitively show that the laws of physics stayed constant over the 14 years of the experiment. "Still, they can now say this with five times more certainty than they could a decade ago," Chen writes. "And if it holds true for Earth's location in the universe, it's not too much of a leap to imagine it's true elsewhere."

Comments

Re:talk about watching paint dry

[jellomizer]

A quote from TFA:
"Most of it is automated, but someone watches it all the time, and someone carries a beeper."

They are not watching the clock tick. but they are making sure the conditions stay consistent, and all parts are working.
A physical person watching a clock to see it going off by a nanosecond isn't possible.

Re:How would they know?

[lgw]

Any change would also affect the observer and the measurement device.

Ever tried to debug a problem from timestamps in log files, where the problem turned out to be clock drift? Non-trivial for sure, but possible.

What this experiment shows is that the clocks kept the same time as one another). That's something. It doesn't really show that the laws of physics are the same everywhere, just that any gradient is quite shallow across the small area the Earth traversed during the experiment. Still, it's worthwhile to do such diligence, because the underlying assumptions are so very fundamental to scientific thought that no one questions them in other work.

Experiments that confirm what everyone assumes to be true, assumes at such a deep level that its below conscious thought, those are valuable.

Still, Feynman one talked about how we could be sure there was not another fundamental force because of a similar experiment: the attraction between two uncharged masses was measured over months with extraordinary precision, and the results were as expected. That was wrong. The experiment simply wasn't accurate enough to detect dark energy, pulling the masses apart every so slightly. And dark energy is the dominate force at work in the universe, so it's a heck of a thing to miss.

So, keep doing experiments to confirm our most basic assumptions, because we can never be sure we aren't missing something.