Clock accurate, 1 second in 300 BILLION years

https://phys.org/news/2022-02-ultraprecise-atomic-clock-poised-physics.html

@sonhouse
Previous atomic clocks have been used to show change in flow of time going up and down 6 feet or so.

This new technology allows that measurement to be accurate from a one MILLIMETER change in altitude.

@sonhouse

There was a somewhat related story (different research group) that mentioned gravity fields affect the flow of time -- I did not know that!

https://www.vice.com/en/article/jgmbdg/scientists-make-breakthrough-in-warping-time-at-smallest-scale-ever

So what do they do for the clocks on the ISS or spaceships? Do they calibrate them to account for the difference in gravity, or just let them run wild and get out of sync with Earth clocks?

@Kevin-Eleven
I think it goes something like this: There is a spacecraft flying around space and it has an atomic clock onboard.

It will run some different from one in a lab or space tracking facility because time flow varies depending on gravity and also on velocity, two separate kinds of physics but they both bend the flow of time. So for syncing the two clocks, it pays to know the trajectory of the spacecraft and the change in time flow can be calculated and that calculation then shows the difference and you effectively sync the two clocks. Time flows faster away from gravity. The more gravity, the slower time flows. The same thing happens when you get close to the speed of light, for different reasons, time flow slows down and would theoretically stop altogether if one managed to go to the speed of light.
That effect is what leads scientists and sci fi writers to speculate about actually going so close to the speed of light.

The idea is if you go say 99.999% of c (speed of light) you might slow your time flow down 100 to 1, so if you visit a star 100 light years away, YOU think the journey only took ONE year and you indeed are only one year older.
Now you spend say ten years studying that great star system, and go back to Earth.
So now you are 11 years older and the trip back takes an extra year so you are 12 years older but you are some 212 years into your own future because time flow back on Earth never changed, it was YOU who slowed down because of your velocity getting so close to c.

@sonhouse
Thanks!

@Kevin-Eleven
There have been dozens of sci fi stories based on the idea of establishing an interstellar civilization in spite of the speed of light, so they all go close to c and financial institutions are formed to stop someone from depositing a few hundred bucks in a bank account and coming back 200 years later expecting to get all that interest so they remove that incentive.

If there was a star with Earth like planets within a hundred light years or so and we managed to get there and establish Earth life there and it takes say 200 years to get there, that is a long time in human terms but in the big picture, compared to the age of mankind, which is measured in units of a hundred thousand years so it could be done, an interstellar civilization in spite of the limit of c.

There are variations on that theme, one being spaceships that could only go say one tenth c, now it takes 40 years to get to Alpha Centauri and that could work but at one tenth c, there is not much gain in time flow so you start out as a 20 year old, you will be near 60 when you get there.
So the science of the time developed hibernation technology that can put you out for that whole time so you end up still being 20 or so at the end of that journey.

Then there is the multigenerational ship where the whole population is awake and it might take a thousand years to get to target, so the majority will never see land.

The " book of the Long Sun' by Gene Wolfe is one of those.

@sonhouse

I was a Clarke and Stapledon head at an early age, so I have to wind myself back a little to consider economic issues. 😉

@Kevin-Eleven
If we do get time bending speeds in interstellar space, there will have to be changes to the way banks do business. I bet some man or woman goes out, comes back a hundred years later or so and actually DID put money in CD's or some such and get back to find their bank account is in the millions.

They would get away with it but I imagine the laws would change pretty quickly after that.

@sonhouse said
https://phys.org/news/2022-02-ultraprecise-atomic-clock-poised-physics.html

@Kevin-Eleven
I think atomic clocks on space craft just run and they use the time differences shown to account for the altitude above Earth and the change in time due to velocity.

@sonhouse said
@Kevin-Eleven
There have been dozens of sci fi stories based on the idea of establishing an interstellar civilization in spite of the speed of light, so they all go close to c and financial institutions are formed to stop someone from depositing a few hundred bucks in a bank account and coming back 200 years later expecting to get all that interest so they remove that incen ...[text shortened]... , so the majority will never see land.

The " book of the Long Sun' by Gene Wolfe is one of those.

@wildgrass
Except the science was bogus, so far no indication of going faster than light, maybe a wormhole someday but time shifts could be anything, a second, a billion years, no telling.