[HN Gopher] OpenBSD Adds Support for Coordinated Mars Time (MTC) ___________________________________________________________________ OpenBSD Adds Support for Coordinated Mars Time (MTC) Author : dbolgheroni Score : 132 points Date : 2021-04-01 18:36 UTC (4 hours ago) (HTM) web link (marc.info) (TXT) w3m dump (marc.info) | gerdesj wrote: | We already had GMT which ended up being called UTC - "Universal". | If we'd stuck with GMT or defined E(arth)TC or similar, then MTC | would make sense. | | I do like it though, good to see some innovation in the AFD jokes | department. | HugoDaniel wrote: | Alien technology | cproctor wrote: | This could really bite you: | | > It is currently not possible to use ssh to login between | systems on MCT and any earth time zone | cphajduk wrote: | need to set the SSH timeout to 44 minutes. | koolba wrote: | Also make sure you're not behind a NAT that drops what it | thinks are idle connections. | | Full handshake requires a few hours of round trips. | zeristor wrote: | What about leap seconds for Mars? | kevwil wrote: | Honestly, no idea if this is an April Fool's Day prank or not. | Seems reasonable, but inconsistent naming makes me suspicious. | wongarsu wrote: | Coordinated Mars Time (MTC) is an actual thing [1]. The | abbreviation follows from UTC, which is abbreviated that way | because English speakers wanted CUT (coordinated universal | time) and French speakers wanted TUC (temps universel | coordonne), so we compromised on an abbreviation that works in | neither language (I wish I was joking). | | The commit going on to call the config TZ=MCT could totally be | a typo that will persist for eternity, just like the "referer" | header. | | 1: | https://en.wikipedia.org/wiki/Timekeeping_on_Mars#Coordinate... | jamesfmilne wrote: | I bet the MCRN Rocinante's computers are running OpenBSD. | lsllc wrote: | So, what you're saying is that 2307 is going to be the year of | the OpenBSD Desktop? (on Mars at least, the Earthers probably | use NetBSD and the Belters FreeBSD). | bpodgursky wrote: | To be pedantic, it was only the MCRN Tachi. "Now" it's just the | Rocinante. | HeckFeck wrote: | It's the only OS the protomolecule couldn't breach. | gbrown_ wrote: | Doors and corners... | lsllc wrote: | Please, let's _not_ have SST on Mars! (Sol-light Savings Time) | haddr wrote: | What about Belters? | gbrown_ wrote: | For Beltalowda! | 082349872349872 wrote: | Judging from the extant _lang belta_ vocabulary, Belters are | likely on an ISO week date calendar. They have 7 weekday names | but don 't seem to bother with our months, and they celebrate | (a presumably earth calendar based) New Year. (calculating new | years day relative to week 1 is probably for them the | introductory CS equivalent of calculating easter for us. | _Seritenyidiye_ , "a 30-day", exists as a word for month, but | probably refers to the earth concept, among those unlucky | enough to have to interface with earth calendars.) | | Beltalowda showxa ere tim wit: | https://en.wikipedia.org/wiki/ISO_week_date keya? Beltalowda | tili du pati (wit walowda walowda dansa unte walowda walowda | rowm unte da adewu "Piyat Minut"?) fo Yitim unte showxa ere | Mundiye, Tusidiye, unte kopeng. Amash beltalowda na tenye wowt | fo "months" tumang. Imalowda tu inya, tu "legacy", sasa ke? | imwm wrote: | "mars can't wait" lol | anthk wrote: | Well... | | https://astro-gr.org/openbsd/ | znpy wrote: | I wonder if SpaceX has anything to do with this. | znpy wrote: | I'm getting downvoted... Of course I forgot today is April 1st. | yellowapple wrote: | I know this is probably an April Fool's joke, but I'd be thrilled | if this was real. | BuildTheRobots wrote: | I'm almost certain it's a joke, the question is for how much | longer? The crypto interoperability issues are amusing, thiugh | I do seriously wonder how you deal with anything from a 10 to | 40 minute round trip time. | ronsor wrote: | You have caching servers and set really, really long | timeouts. | wongarsu wrote: | The same way we deal with speed-of-light delay on earth: | CDNs, asynchronous protocols like email, or just ignoring it | when we can get away with it (e.g. "instant" messaging). SSH | might be a bit tricky, but just pretend your system on mars | is a production server and send it a tested bash file (using | any of your favorite automation tools). | Fern_Blossom wrote: | Same here, this is so far the best one yet. Far better than | VW's shitty attempt. | | Though, it dawned on me, Mars could have _real_ time zones. Not | the stupid political mess we have today. Perfect, logical | longitudinal time zones from the get go. That right there is | more than enough reason for me to leave this planet. | | But let's be honest, Mars will be colonized, politics will | arise and the same fuckery will happen eventually. | monocasa wrote: | Better yet, no time zones. Just one clock for the planet. | jakear wrote: | Obligatory https://qntm.org/abolish | monocasa wrote: | When you're already destroying enough of the legacy | timekeeping systems by switching to a planet without a 24 | hour day, most of those arguments lack muster. | | Also, don't call people out of the blue and expect them | to pick up anyway. Maybe your uncle had to work late and | is sleeping even though the sun is technically out. | elygre wrote: | If they are zones, how can they be perfect? The middle might | be, but anywhere else will be imperfect. | yellowapple wrote: | You're right. We need to constantly adjust our clocks | depending on exact longitude. | midasuni wrote: | And velocity. And altitude. | nwallin wrote: | A time system useful on Mars needs additional consideration; | considerations we haven't given it yet. It requires more | thinking than just time zones. The various things we've sent to | Mars haven't had any need for a colloquially time; they're | computers, they just know that 21,872 seconds or whatever into | the day is that far into an 87,755 second day and that's good | enough to calculate shadow angles and expected solar panel | efficiency from. | | If we were to build a colony on Mars with normal people doing | normal everyday things, we need something more than that. The | first question we want to ask ourselves is, do we want to keep | the SI defined second? If we don't care, then we have free | reign to do whatever we want. We can define a Mars second to be | 1/86,400th of a Mars day, and keep the 24 hour, 60 minute, 60 | second time system we use on Earth. Or we switch to a metric | time system, with a 10 hour day, 100 minute hours, 100 second | minutes. Or a 1 day long day, and deci, ceni, milli, micro | days. Or whatever. | | If we want to keep SI compatibility, we need to keep the | second. The Martian solar day is 87,755.224 seconds long. | 87,755 factors into 5^2 * 53 * 67. So we can do 25 hours per | day, 53 minutes per hour, 67 seconds per minute to give an | 87,755 second day. Unfortunately there would need to be a leap | second once every 4-5 days. | | Then there's the question of the calendar. Perhaps fortunately, | this gives us the opportunity to restart from scratch, because | the calendar we use is such a goddamned clusterfuck, even worse | than our time system. Unfortunately, the number of days in a | Martian year (668 and change) does not lend itself to a clean | division into tidy periods. You could have 23 months of 29 days | each, with each month having 4 7 day weeks plus one holiday. | This will give you a 667 day year. Add another annual holiday | at the beginning of the year, plus an optional leap-holiday in | the middle of the year. | | Or you could split it up into 37 months of 3 weeks, each with 6 | days. This gives you a 666 day year, so sprinkle in 2-3 bonus | holidays per year. | | There are a lot of considerations. It needs to be given more | thought. Hopefully more thought than we've given to Earth's | timekeeping systems. | skissane wrote: | > The first question we want to ask ourselves is, do we want | to keep the SI defined second? | | I think absolutely yes. Any Mars colony is going to import a | lot of equipment and technology from Earth. All of that is | going to assume the SI second. Not just for measuring time, | but also as part of the definition of derived units such as | Newtons. Martian colonists will have no practical choice but | to use the SI second since all their Earth-manufactured | equipment is going to assume it. | | Plus, if they tried to introduce a distinct Martian second, | soon they'd have a mix of SI units (based on the SI second) | and slightly different Martian units (based on the Martian | second), and that would produce Mars Climate Orbiter style | disasters. | | > Perhaps fortunately, this gives us the opportunity to | restart from scratch | | People won't. People will want to use the Earth calendar | because they are keeping in sync with Earth news and Earth | culture. Maybe after a few centuries, Mars will feel | sufficiently independent from Earth, that it might want to | introduce a new calendar. However, by then Martians will be | thoroughly used to the Earth calendar, it will be a | centuries-old part of their Martian culture heritage, and | they probably won't want to change it. | kryptiskt wrote: | It's not a future problem, JPL personnel already work after | Mars time: https://www.businessinsider.com/nasa-perseverance- | team-mars-... | kibwen wrote: | Days, months, and years based on the cycles of the planet | make sense on Earth, but not as much on Mars. | | Almost all Martian settlers will be living underground, and | even aboveground the light at mid-day is extremely dim. You | can set the day to whatever length you want, regardless of | the Martian sol, and nobody will notice. | | Likewise, months and years on Earth are for tracking | agricultural seasons, but nobody will be growing crops on the | Martian surface. Set the year to whatever you want, with or | without months, and no civilians will notice. | PeterisP wrote: | For a person living on Mars it makes sense to align the time | to Martian solar day iff their daily life is linked to | outdoors activities in sun. However, if they are expected to | stay indoors or even underground facilities (which IMHO is | very, very likely at least for the first decades for various | reasons) then the outdoors day is simply irrelevant, and it | makes all sense to coordinate with Earth time for all your | activities and just look up local solar time only when you | need to schedule activity outside the base in the | "wilderness" - where you're anyway going to spend just some | hours, not a whle day/night cycle. | zokier wrote: | If we are to send people to Mars then presumably we want | some interaction with the surface. Otherwise we might as | well send those people to underground bunkers on Earth. | Zenst wrote: | It certainly does raise a forward thinking issue and that is | networking across planets and TZ handling. TZ's are already a | PITA what with leap seconds. | | Then there is defining standards on Mars, 24hour days kinda not | going to translate, so again, more forward thinking needed. As | for Mars GPS, bit of a way off, but I'm sure the good old | atomic clocks will work. | | I guess the job title of "Systems Engineer of Time" may become | a reality one day after all. | skissane wrote: | > 24hour days kinda not going to translate | | The Martian day, called a "sol", is about 24 hours 39 minutes | 35 seconds. So it is just a bit longer than an Earth day. Of | course, that extra 39 minutes and 35 seconds adds up - after | a bit over a month, it adds up to a whole Earth day, and a | count of sols would be one behind a count of Earth days. | | Idle speculation: I reckon people on Mars may initially use a | hybrid calendar of Mars days (sols) but Earth years. They'd | want to use the sol because they'd want to keep in sync with | Mars day-night cycle, especially since that would be | important for when they go outside and do stuff (in their | spacesuits). On the other hand, they'd still be in heavy | communication with Earth and absorbing a lot of Earth news | and Earth culture, so they'd likely want to keep the Earth | year. The Martian year is longer (about 22.5 months long), | and it would likely have less significance to them - Mars has | seasons, but seasons only have limited relevance when you | have to spend all your time indoors. | seiferteric wrote: | Kind of makes me wonder about local time on a space ship | going some significant % of the speed of light. Time itself | would be at a different rate than back home. Perhaps we need | to introduce the concept of a space-time zone. | zokier wrote: | We have few time standards that already take relativity | into account: | | https://en.wikipedia.org/wiki/Barycentric_Dynamical_Time | | https://en.wikipedia.org/wiki/Barycentric_Coordinate_Time | | https://en.wikipedia.org/wiki/Geocentric_Coordinate_Time | wongarsu wrote: | The most practical solution is probably to introduce a | global time beacon, like a satellite broadcasting it's own | time, or everyone counting the flashes of some known | pulsar. Then you have one time reference everyone agrees | on, it just ticks at different speeds depending on how fast | you are moving. | | Luckily so far the practical propulsion concepts we have | max out around 10% the speed of light for reasonable | amounts of propellant, so we have a couple decades left to | figure this out. | vsareto wrote: | Writing some test software based on Martian time might be a | good way to prevent some DateTime issues when we do start | living there. | korethr wrote: | The best April Fools jokes are the ones with enough | plausibility that they _could_ be real. | jamal-kumar wrote: | Imagine reading: | | "DANGER: ABI incompatibility. Updating to this kernel requires | extra work or you won't be able to login: install a snapshot | instead" | | and raging | sfblah wrote: | It mentions the days being longer, but what about the years? What | even constitutes a year on Mars? Seems like more thought needs to | go into how this would work if/when we become interplanetary. | Assuming knowing where you are in the year has any value on Mars, | we'd want some way to track that. I wonder also how this would | work on the moon. | 4147eded-4d4f wrote: | My background is physics and during an extended beer session my | group talked extensively about what properties an | interplanetary time keeping system would need to have. | | The answer we came up with was: thank god we'd be retired or | dead by the time it became a problem that we had to deal with | day to day. | | You would need something like international atomic time to be | the basis for it, but unlike TAI which is the weighted average | of some 400 atomic clocks on the surface of the planet, you | would need to define it with respect to free space (which we | can't access) and with respect to a single event that's | accessible to everyone yet human scaled enough that it happened | in written history (the best we came up with was the first | nuclear blast). | | Then you would need to have a calculation that turned it into | local time which would be completely decoupled from any actual | time keeping. Think printing the result of a square root in | Roman numerals vs trying to do the calculation in Roman | numerals. | | Unix epoch is laughably inadequate for anything like that. | Basically we have nothing today and you'd need an international | agreement to have a sane time keeping system going forwards. | swiley wrote: | Judging by DST and the gregorian calander I'm sure we'll end | up with a system that doesn't even approach the utility of | what you're thinking. | | Everyone will probably just use Eastern Time on mars complete | with Daylight saving, _maybe_ TAI if we 're lucky. | smitty1e wrote: | One anticipates a network that operates with a faster-than- | light "because" pipe, or you just have a planetary local NTP | server and let something upstream do the Einsteinian | gymnastics with the timestamps. | wahern wrote: | What's wrong w/ TCB | (https://en.wikipedia.org/wiki/Barycentric_Coordinate_Time) | and TDB | (https://en.wikipedia.org/wiki/Barycentric_Dynamical_Time)? | yellowapple wrote: | Probably best to just drop the notion of "days", "years", etc. | entirely, and instead just track the number of kiloseconds, | megaseconds, etc. since the Unix Epoch. | jhgorrell wrote: | In the novel "A Deepness in the Sky" by Vernor Vinge, the | characters tell time this way. I had to do some math early in | the book to get a feel for what 1Msec & 1Gsec was. | | In addition, they also keep track of their cold sleep time, | because if you want to meet your spouse 50 years from now, | you want to try and keep the same relative age. | zrm wrote: | Since the Unix Epoch where? Isn't being on another planet | going to have to deal with the relativistic passage of time? | bonzarm wrote: | France used the decimal time for a few years beginning in | 1792 during the French Revolution. It didn't go well. | yjftsjthsd-h wrote: | I was under the impression that the OS _did_ only track time | in seconds since the epoch, and whenever you see something | else it 's just the software translating for human | convenience. If that's the case, then it this doesn't really | make sense; humans will want something friendlier than epoch | time on Mars, too. | bonzini wrote: | Sort of. Unix time does not count leap seconds, all days | are 86400 seconds long in Unix time. So the actual number | of seconds since the epoch is a bit larger than what time() | returns. | | I don't know how Windows deals with leap seconds (its epoch | is in 1601 or something like that). Edit: it doesn't, the | clock goes 1 second ahead of UTC and it's then fixed by | NTP. | pedrocr wrote: | So time() is actually days since epoch with 1/86400 | precision. That makes the Google solution to smear leap | seconds with NTP instead of making them explicit make | even more sense. | rzimmerman wrote: | It's technically even more complicated than just scaling the | day/seconds by to match a Martian sol. There are relativistic | corrections that add up over time (Earth clocks would observe | Mars clocks ticking at a different and non-constant rate). Good | thing this is real :) | fsh wrote: | This is already the case on earth. UTC is defined at sea level | and clocks run faster at higher elevations due to the lower | gravitational redshift. This effect is easily observable with | atomic clocks and has to be taken into account in any accurate | clock comparison. ___________________________________________________________________ (page generated 2021-04-01 23:00 UTC)