4 ms·

Vernor Vinge had it figured out in A Deepness in the Sky with the use of kiloseconds, megaseconds, and gigaseconds.

by clem 1y ago

BurningFrog 1y ago
A second is still originally defined as 1/86400 of an Earth day. That doesn't make it unusable as a cross galactic time unit, and I think the same goes for years and hours.
- gleenn 1y ago
  Case-in-point, you are mistaken. The duration of a day changes due to many things, both logically and also physically due to the nature of Earth. Also just because you can call a second a second doesn't mean that is helpful making datetime software usable or easy on a different planet.
  - mikepurvis 1y ago
    I think he's speaking historically. Obviously now a second is a fundamental SI unit defined in terms of physics experiments, but the origin of it was as the amount of time that was 1/3600th of an hour of which there are 24 in the day.
    - shadowgovt 1y ago
      Similar to how almost-pi-squared meters-per-second shows up in the constant for gravitational acceleration near Earth's surface because the meter was originally "the length of pendulum that ticks once a second" and there's a pi in the pendulum motion equation. (... it's not exactly pi-squared because the French yanked it around a bit before settling into the modern number based on light in a vacuum and cesium atoms).
- layer8 1y ago
  The issue is that planetary locales will each have their own days and years (and possibly hours), so it would be confusing to adopt that same nomenclature for an interplanetary/interstellar time unit. And since the latter will be inconsistent with local time systems anyway, it’s easier to just have it use powers of ten. At least until we meet aliens that may prefer a different base.
  - deleted 1y ago
    [deleted]
  - BurningFrog 1y ago
    I was 100% thinking of use by humans living on other worlds. Pretty sure Mars will use seconds and hours. Handling dates will awkward whatever they decide on. Currently, a Mars days is called "sol", FWIW. If we find other species out there I won't speculate on how they think about time.
  - GoblinSlayer 1y ago
    But this makes no sense, humans can't just change their circadian rhythm to match an arbitrary daylight cycle, and clocks aren't necessarily reconfigurable. And with a good enough artificial lighting you don't need to depend on star. Daylight is just weather, it has nothing to do with how calendar works.
- ceejayoz 1y ago
  Seconds are now (in SI) defined as calculated from behavior of cesium-133 atoms. https://en.wikipedia.org/wiki/Caesium_standard https://en.wikipedia.org/wiki/Caesium_standard
  - BurningFrog 1y ago
    You can also define "days" and "years" in terms of that SI definition. I don't think that helps with the original concern.
    - ceejayoz 1y ago
      You can, yes. But having it all stem from some fundamental constant value any civilization can handle permits translation between civilizations. "Our dates start x trillion rotations of pulsar y ago and our unit is defined as z wiggles of cesium" is a starting point.
  - bunderbunder 1y ago
    9,192,631,770 is clearly a sensible number and not something that's blatantly chosen to match some arbitrary pre-existing geocentric standard like 10,000,000,000 would have been.
    - ceejayoz 1y ago
      It's retrofitted to what we already defined as a second, sure. But you can tell an alien species our units are expressed in multiples of that, and they can translate it into how theirs works. (Vinge, for example, has space-faring humans talk about "megaseconds" and "gigaseconds" rather than days/years.)
      - db48x 1y ago
        > "megaseconds" and "gigaseconds" rather than days/years. More like weeks and decades. Arranging to meet someone in a megasecond is like meeting them on the weekend; a megasecond is ~11.5 Earth days. A kilosecond is short enough to be used for moment–to–moment planning. They’re about a quarter of an hour each so they’re good for scheduling work tasks, scheduling time to meet people for a meal, etc etc. Gigaseconds are more rarely used, since each one is ~32 Earth years. Diaspora by Greg Egan has some fun with this too. The main character is a software emulation; called a citizen rather than a flesher. Most emulations live at a subjective rate 800× faster than the flesher normal. The second chapter is three flesher days after the first but 256 megatau, or ~8 years, have passed for the main characters. The fourth chapter is two thirds of a teratau later, over 20k subjective years. For the fleshers of Earth a mere 21 years have passed. The main character has actually forgotten the events of the third chapter; one of his friends brings it up and he has to search his archived memories to figure out what his friend is talking about.
greggyb 1y ago
Coming from an educational background of imperial units, I sometimes catch flak from ... most of the world about this. I take joy in exuberantly pushing back on their insistence of clinging to such archaic time units as "minutes", "hours", and "days", telling them to come back when they embrace kiloseconds. It is telling that most of my friends accept this with equal joy and laughter (: It probably doesn't hurt that I've also spent time drilling metric conversions so that I can code-switch pretty seamlessly among units. Neurotic tendencies can have payoffs.

Vernor Vinge had it figured out in A Deepness in the Sky with the use of kiloseconds, megaseconds, and gigaseconds.

by clem 1y ago

Vernor Vinge had it figured out in A Deepness in the Sky with the use of kiloseconds, megaseconds, and gigaseconds.

A second is still originally defined as 1/86400 of an Earth day. That doesn't make it unusable as a cross galactic time unit, and I think the same goes for years and hours.

gleenn 1y ago
Case-in-point, you are mistaken. The duration of a day changes due to many things, both logically and also physically due to the nature of Earth. Also just because you can call a second a second doesn't mean that is helpful making datetime software usable or easy on a different planet.
- mikepurvis 1y ago
  I think he's speaking historically. Obviously now a second is a fundamental SI unit defined in terms of physics experiments, but the origin of it was as the amount of time that was 1/3600th of an hour of which there are 24 in the day.
  - shadowgovt 1y ago
    Similar to how almost-pi-squared meters-per-second shows up in the constant for gravitational acceleration near Earth's surface because the meter was originally "the length of pendulum that ticks once a second" and there's a pi in the pendulum motion equation. (... it's not exactly pi-squared because the French yanked it around a bit before settling into the modern number based on light in a vacuum and cesium atoms).
layer8 1y ago
The issue is that planetary locales will each have their own days and years (and possibly hours), so it would be confusing to adopt that same nomenclature for an interplanetary/interstellar time unit. And since the latter will be inconsistent with local time systems anyway, it’s easier to just have it use powers of ten. At least until we meet aliens that may prefer a different base.
- deleted 1y ago
  [deleted]
- BurningFrog 1y ago
  I was 100% thinking of use by humans living on other worlds. Pretty sure Mars will use seconds and hours. Handling dates will awkward whatever they decide on. Currently, a Mars days is called "sol", FWIW. If we find other species out there I won't speculate on how they think about time.
- GoblinSlayer 1y ago
  But this makes no sense, humans can't just change their circadian rhythm to match an arbitrary daylight cycle, and clocks aren't necessarily reconfigurable. And with a good enough artificial lighting you don't need to depend on star. Daylight is just weather, it has nothing to do with how calendar works.
ceejayoz 1y ago
Seconds are now (in SI) defined as calculated from behavior of cesium-133 atoms. https://en.wikipedia.org/wiki/Caesium_standard https://en.wikipedia.org/wiki/Caesium_standard
- BurningFrog 1y ago
  You can also define "days" and "years" in terms of that SI definition. I don't think that helps with the original concern.
  - ceejayoz 1y ago
    You can, yes. But having it all stem from some fundamental constant value any civilization can handle permits translation between civilizations. "Our dates start x trillion rotations of pulsar y ago and our unit is defined as z wiggles of cesium" is a starting point.
- bunderbunder 1y ago
  9,192,631,770 is clearly a sensible number and not something that's blatantly chosen to match some arbitrary pre-existing geocentric standard like 10,000,000,000 would have been.
  - ceejayoz 1y ago
    It's retrofitted to what we already defined as a second, sure. But you can tell an alien species our units are expressed in multiples of that, and they can translate it into how theirs works. (Vinge, for example, has space-faring humans talk about "megaseconds" and "gigaseconds" rather than days/years.)
    - db48x 1y ago
      > "megaseconds" and "gigaseconds" rather than days/years. More like weeks and decades. Arranging to meet someone in a megasecond is like meeting them on the weekend; a megasecond is ~11.5 Earth days. A kilosecond is short enough to be used for moment–to–moment planning. They’re about a quarter of an hour each so they’re good for scheduling work tasks, scheduling time to meet people for a meal, etc etc. Gigaseconds are more rarely used, since each one is ~32 Earth years. Diaspora by Greg Egan has some fun with this too. The main character is a software emulation; called a citizen rather than a flesher. Most emulations live at a subjective rate 800× faster than the flesher normal. The second chapter is three flesher days after the first but 256 megatau, or ~8 years, have passed for the main characters. The fourth chapter is two thirds of a teratau later, over 20k subjective years. For the fleshers of Earth a mere 21 years have passed. The main character has actually forgotten the events of the third chapter; one of his friends brings it up and he has to search his archived memories to figure out what his friend is talking about.

greggyb 1y ago

Coming from an educational background of imperial units, I sometimes catch flak from ... most of the world about this. I take joy in exuberantly pushing back on their insistence of clinging to such archaic time units as "minutes", "hours", and "days", telling them to come back when they embrace kiloseconds. It is telling that most of my friends accept this with equal joy and laughter (: It probably doesn't hurt that I've also spent time drilling metric conversions so that I can code-switch pretty seamlessly among units. Neurotic tendencies can have payoffs.