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The Unix timestamp will begin with 16 this Sunday

unixtimestamp.com

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Re: The Unix timestamp will begin with 16 this Sunday

#61

Post by gerikson »

shantara wrote: post #44
jezze wrote: post #37

When we one day become a space faring civilization we will probably stop using the gregorian calendar because why would you use that on say Mars? 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.

In "Deepness in the Sky" a spaceship's computer is still running on Unix time many thousands years into the future. It is generally believed that the calendar starts with the first Moon landing, and only the main character as a "programmer-archeologist" discovers a small difference between it and true Unix time 0.

"A Deepness..." also used SI multiples of seconds to denote something approximating 24 hours, a week, a month etc.

Re: The Unix timestamp will begin with 16 this Sunday

#62

Post by linkdd »

NGC404 wrote: post #40
jezze wrote: post #37

When we one day become a space faring civilization we will probably stop using the gregorian calendar because why would you use that on say Mars? 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.

Next iteration of unix-time should include the concept of local time in context of relativty if we are going to travel or communicate over significant distances.

Einstein: There is no such thing as an absolute time

Programmer: Hold my beer

Re: The Unix timestamp will begin with 16 this Sunday

#63

Post by disown »

browserface wrote: post #18

The crazy thing is there has only been 1.6 billion seconds since 1970. There have been more babies since 1970 than there have been seconds. Which is crazy. Back then, Earth's population was on 3.7 billion. Now it's 7.8 billion. That means that (ignoring deaths) 2.5 babies have been born for each unix second. Or roughly 1 baby every 400 milliseconds.

Linear vs quadratic growth.

Re: The Unix timestamp will begin with 16 this Sunday

#66

Post by tzs »

mocar wrote: post #32

And today is day 256 of 2020

For those who would like to be able to figure day of year from date in the heads, here are a couple of reasonable ways.

1. Given month 1 

  0, 1, -1, 0, 0, 1, 1, 2, 3, 3, 4, 4
Add the day, and add 1 if it is a leap year and m >= 3.

E.g., September 12. m = 9, giving 240 + F[9] = 243 for Sep 0. Add 12 for the day, and 1 for the leap year, giving 256.

The F table has enough patterns within it to make it fairly easy to memorize. If you prefer memorizing formulas to memorizing tables, you can do months m >= 3 with F[m] = 6(m-4)//10, where // is the Python3 integer division operator. Then you just need to memorize the Jan is 0, Feb is 1, and the rest are 6(m-4)//10.

2. If you have the month terms from the Doomsday algorithm for doing day of week calculations already memorized, you can get F]m] from that instead of memorizing the F table.

F[m] == -(2m + 2 - M[m]) mod 7, where M[m] is the Doomsday month term (additive form): 4, 0, 0, 3, 5, 1, 3, 6, 2, 4, 0, 2.

You then just have to remember that -1 BTW, you can run use that formula relating F[] and M[] the other way. If you have F[], them M[m] = F[m] + 2 m + 2 mod 7. Some people might find it easier to memorize F and compute M from that when doing day of week with Doomsday rather than memorize M.

Re: The Unix timestamp will begin with 16 this Sunday

#68

Post by daveFNbuck »

remram wrote: post #47
NGC404 wrote: post #40

Earlier quoted context omitted.

Next iteration of unix-time should include the concept of local time in context of relativty if we are going to travel or communicate over significant distances.

You mean that from a remote place or fast-moving ship, the time on Earth would appear to go at a different speed? So local time would not just have a constant offset?

If time is moving at a different speed, it wouldn't just be a constant offset. You'd also need a multiplier. Think of two cars moving at different speeds on a road. They don't stay the same distance apart.

Re: The Unix timestamp will begin with 16 this Sunday

#69

Post by Dylan16807 »

BoppreH wrote: post #46
jezze wrote: post #37

When we one day become a space faring civilization we will probably stop using the gregorian calendar because why would you use that on say Mars? 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.

There is a very good reason to eventually abandon it: leap seconds. Unix time goes back one second whenever there is a leap second on Earth. 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 th…

Or we just pretend they never happened.
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