But there really is no reason to get rid of the unix timestamp as a measure of time and this measure may stay around for a long time. This may mean that people in the future might consider 1970 as year zero where modern civilization began.
As opposed to eunuchs.
“Most years, since its inception in 1999, Vinge has been on the Free Software Foundation's selection committee for their Award for the Advancement of Free Software.”[0]
Since “A Deepness in the Sky” was written in 1999 as a prequel to “A Fire Upon the Deep” (from 1992), which do you recommend to read first?
Many people didn't like Deepness much. But the sequel to Fire, Children of the Sky, was interesting.
The Peace War is a fascinating exploration of "what if this one thing was possible?" and all its terrible consequences, but Deepness grabbed me much more as a story.
Another handy time_t approximation is that a year is about 2^25 seconds, or 32 megaseconds.
It's extremely weird and IMHO completely ruins the purpose of a timestamp, but it's a compromise for backwards compatibility, since Unix time was created before leap seconds. This hack ensures that the number of seconds in a day remains fixed, an assumption of many systems at the time.
Ironically, your kernel measures TAI time perfectly happily if unmolested, as that always ticks once for every SI second (ignoring oscillator drift). No slewing. No smearing. No stepping.
Also, "since Unix time was created before leap seconds." I found this interesting for the simple reason I've never spent any time thinking about Epoch vs Leap Second histories.
tm_sec + tm_min*60 + tm_hour*3600 + tm_yday*86400 +
(tm_year-70)*31536000 + ((tm_year-69)/4)*86400 -
((tm_year-1)/100)*86400 + ((tm_year+299)/400)*86400Go and read about "right" versus "posix" timezones.
So it's cyclic and doesn't make sense outside the earth reference frame
Edit: since 2019, 1 second is defined by taking the fixed numerical value of the caesium frequency ∆νCs, the unperturbed ground-state hyperfine transition frequency of the caesium-133 atom, to be 9192631770 when expressed in the unit Hz, which is equal to s−1
So a second makes sense in the galactic scale at least as long as Caesium-133 is a stable isotope in that environment
> realisation of the metre is usually delineated (not defined) today in labs as 1579800.762042(33) wavelengths of helium-neon laser light in a vacuum
"Local seconds since 1970", vs. "Static seconds since 1970".
In a broad sense, the answer goes like this: Almost everything in the galaxy shares an approximate reference frame when it comes to velocity and special relativity. For general relativity and gravity, that's obviously a distortion so it doesn't count.
In the long term, to prevent very minor drift, we can use quasars as a reference.
Number of seconds since a given time seems fine until we're travelling significantly outside of a common reference plane.
Unix time decrees every day has exactly 86400 seconds. But the introduction of leap seconds means that While most days have 86400, some earth days have 86401 seconds and potentially there could also be days with 86399
TAI makes sense everywhere, Unix time only on earth.
Unix time is [...] the number of seconds that have elapsed since the Unix epoch, minus leap seconds.
- Wikipedia
If you are on Mars you'll have to update your computer time every ~6 months when Earth release a new table of leap seconds caused by e.g. earthquakes.
Carl Sagan put a quasar GPS on a golden plaque on both Voyager probes, so future intelligences could tell where and when the Voyagers came from.
How do you even measure a global value when the local perspective by definition changes the value?
Programmer: Hold my beer
Programmer: Next iteration of unix-time should include the concept of local time in context of relativity if we are going to travel or communicate over significant distances.
Einstein: Hold my beer
You don't need science fiction for this.
* https://www.bipm.org/en/bipm-services/timescales/time-ftp/Ci...
In addition, you will probably want clocks that run at a given perceived speed, to time physical processes that take the same time everywhere (e.g. so your cookie recipe saying "bake for 600 seconds" work without translation).
We could eventually arrive at stardates with one starday being 100000 seconds. Of course, that would be just as arbitrary as simply keeping the 24 hours of 60 minutes each.
http://www.chronobiology.ch/wp-content/uploads/publications/...
They were very limited, though. We do not really know what would happen on a spaceship that changed its day to 100 000 seconds and subjected the crew to this cycle for months or years.
Given how adaptable people usually are to external influences, I would guess that some adaptation would take place.