Comments interspersed

On 4/3/25 07:37, Timothy Collinson - timothy.collinson at port.ac.uk
(via tml list) wrote:
> <snip>
>
> What caught my attention, however, was an article on Compact Atomic
> Clocks which revealed that (at the time) they could be accurate to one
> second in 100 million years BUT require a 3m tall vacuum vessel as
> well as extensive electronics racks and optoelectronics components to
> coll the atoms down to micro-Kelvin temperatures.
Guessing from context it's "to _cool_ the atoms down..." ?
>
> However, lower accuracy (1 second in 30,000 years) commercial caesium
> and rubidium clocks had been developed which could typically be housed
> within a 500 x 500 x 130 mm rack-mountable enclosure with thermal
> rather than cold atoms.

>
> And "the last few years" have seen the emergency of chip-scale atomic
> clocks that can fit in a matchbox with a core 'physics package' of
> less than 1cm^3 - accuracy: 1 second in 300 years.
>
> No doubt things have moved on in the last 12 years although I've not
> had time to look at where they are now.

Like so? https://www.ingenia.org.uk/articles/compact-atomic-clocks/

Changes look to have mainly been increased frequency stability and
holdover  - this one https://www.sparkfun.com/atomic-clock.html,
although no longer in stock,  seems to be in the range of 1 second in
3,000 years.

>
> But it did occur to me that perhaps Traveller computers are
> (notoriously) large because, amongst other things, they need to
> contain a really accurate clock.
>
> For:
> - navigation obviously, but also
> - financial transactions (perhaps you can only 'carry' Credits if
> you've got a sufficiently powerful (i.e. large) clock)
> - flexible networks (field networks for combat)
> - secure comms
> - efficient comms
> - sensors
>    (see box on p.27)
>
That actually circles back to having a high-precision time reference
enabling (or, practically, required for) those things.
Especially in TU where the time in-jump can vary between onboard and
offboard observers (eg the _Bangers and Mash_ takes 7 days on the dot
according to its internal clocks, but 8 days 2 hours according to
difference between last starport time received before jump and first
starport time received afterwards), how frequently do ships synchronise
(or "discipline") their onboard clocks with eg starport clocks?
How do different star systems synchronise their clocks to some Polity
Standard Time?

I suspect the required precision would be at least as high as modern-day
- where the atomic clocks on NAVSTAR satellites (and, I presume other
satnav systems) are corrected to run at (frinstance) 10 Mhz _from the
reference frame of the ground_ - onboard, it's something like (I think)
a few Hz greater (making NAVSTAR et al great, and continuing, tests of
general relativity).  This would be purely for worldbuilding, but
general-relativistic timing corrections would not be trivial to work out
between systems with a 2 week ping time.

However, if accurate to second-per-millennium clocks are _commercially_
available _now_, would that be good enough for C57 civilian traffic
traipsing through the main routes of charted space (or C22 civilian
traffic traipsing around the main routes of Ushuggi), syncing up during
starport visits?
That caesium clock you mentioned occupies 0.04 cubic metres - or less
than 0.004 dtons.  With (I _think_) costs of ~50k USD each _now_, that's
what, 60k CrImp for three (WHAT DO when two clocks aboard ship
disagree?), taking up three-fifths of sod-all space?  Compared to the
cost of even a Scout ship, that's epsilon.

I lean towards the option taken in GT: Interstellar Wars, where most of
the volume of a Traveller "computer" is taken up by stuff not subject to
Moore's law - stuff like sensors, governed by more mundane things like
the laws of physics.
As computronium _is_ subject to Moore's Law (or something like it), I'm
not seeing how financial transactions would _require_ a beefy computer.

Could you expand more on secure/efficient comms?

Alex