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Here's How We'll Keep Time on Mars - Nerdist:
Now that humanity has a decent shot at sending people to Mars, it's as good a time as any to think about the kinds of lifestyle challenges the Red Planet will pose. For instance, time itself will have to change in a significant way. As this new video from YouTube channel RealLifeLore explains, people will have to rethink what a "year" or "day" means to them. (Kind of like what happened in 2020.)
[...] These changes result in the Martian day (or Sol) being slightly longer than Earth's, at 24 hours and 37 minutes. Mars' year being much longer, at 687 Earth days. However, a "second" is equal on both planets; a second defined as a particular number of radiation cycles of a cesium-133 atom, which remains unchanged anywhere in the universe. But they still end up requiring different senses of how long a "day" or "year" is.
(Score: 0) by Anonymous Coward on Thursday December 31 2020, @09:20AM (2 children)
Yes.
(Score: 4, Funny) by driverless on Friday January 01 2021, @05:59AM
I think my mother-in-law will be moving there shortly, then she'll finally be the age she tells people she is.
(Score: 0) by Anonymous Coward on Friday January 01 2021, @01:48PM
Why would I want to send my mule to Mars? Wouldn't a robot be more useful than a beast of burden? A robot wouldn't need a space suite for a start.
(Score: 3, Insightful) by Dr Spin on Thursday December 31 2020, @09:42AM (1 child)
An earth year is a year. It will not change. A complete rotation of Mars around the sun is not an earth year. It is something else. Perhaps a "mear"?
Personally, I would prefer a beer, but that might add to the confusion instead of reducing it.
As for a rotation on its own axis - as long Americans are involved, lets call it a "pay".
Warning: Opening your mouth may invalidate your brain!
(Score: 2, Informative) by Anonymous Coward on Thursday December 31 2020, @08:53PM
That would make a whole bunch of unfortunate names: vear, jear, sear, and near. What would you recommend for Mercury and Uranus? Rear and quear?
(Score: 5, Insightful) by maxwell demon on Thursday December 31 2020, @09:42AM (9 children)
Will the Mars year be of any significance? Given that you'll not be living under a natural climate, I guess it will not be too significant, except maybe if you are close to the poles. Possibly the more important measure will be the time between two Earth-Mars oppositions, as that determines how hard it is to get new supplies fro Earth, as well as the signal delay in Earth-Mars communication.
The Tao of math: The numbers you can count are not the real numbers.
(Score: 2) by fakefuck39 on Thursday December 31 2020, @11:06AM (5 children)
Yeah, this is exactly the right point to make. What matters to humans is the day, not the year. So the mars year, for daily lives is not significant. The day is about the same, so our sleep cycle should be fine. Now as fars as issues of earth and mars being slowly more and more out of sync over several days, that problem has been solved. As someone who's hopped on over 2k flights, traveling between many timezones, the solution comes from all the thousands of consultants I see on the plane every morning - a issue of mismatching timezones. And the solution is very simple, because the problem is very simple. When you need to work together, you schedule your ship for a time when both parties are available - problem solved.
(Score: 2) by PiMuNu on Thursday December 31 2020, @11:52AM (4 children)
Leap years are enough of a faff. Now day length as a variable gets added to *every* PC in the world... think of the bugs!
(Score: 3, Informative) by fakefuck39 on Thursday December 31 2020, @12:19PM
that's already the case though - we add a few seconds to a day every few years or so just like we add a day to the year every few years. this is because the earth's rotation is slowing.
https://www.timeanddate.com/time/leapseconds.html [timeanddate.com]
(Score: 3, Insightful) by istartedi on Thursday December 31 2020, @05:59PM (1 child)
Internally maintain seconds from epoch. Format the output based on locale. It's not too bad if things were designed properly so... yeah. Lots of bugs.
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(Score: 3, Insightful) by PiMuNu on Friday January 01 2021, @11:19AM
I was comparing with Y2K bug, but I guess that was more low level/insidious to deal with (i.e. "maintain seconds from epoch" was broken). Nonetheless...
(Score: 0) by Anonymous Coward on Friday January 01 2021, @08:55AM
Because Mars is further from the Sun they are going to want as much sunlight as possible. Expect daylight-savings year round, and probably double-daylight-savings during the Mars winter.
(Score: 3, Interesting) by canopic jug on Thursday December 31 2020, @04:20PM
Like in other comments, it is essential to note that those living on Mars will probaly be underground most of the time and indoors nearly all of the time when at the surface. In both cases it would mean artificial lighting. So it would make sense to just stick with one time for the whole planet. Since UTC is already a standard and used for international coordination, it can serve just as well for interplanetary coordination.
Furthermore, it would not matter that much that the outdoors there has a different day-night cycle. It would be analagous to keeping track of the tides along the coasts. We already deal with a different time cycle along the coasts with the tides and have for ages. It is so ingrained in the local culture that if you're along the coast, you don't give it a second thought but have various means of knowing when the tides are for your area. However, if you are a bit away from the coast, the idea never occurs to anyone. So those on Mars could have their regular time, UTC, and then keep track of the outdoors situation by means of a Mars schedule like we do for the tides. Although, their calculations would be far less complicated than figuring out the tides, since there are no sunlight equivalents for bays, fjords, or storm surges to affect the time of sunrise or sunset out there.
Money is not free speech. Elections should not be auctions.
(Score: 2) by Immerman on Thursday December 31 2020, @04:22PM
Definitely so, assuming lots of solar power - the daily yield will vary dramatically with the seasons.
So will the weather - dangerous dust storms will be far more likely some times of year. And if you're near the poles frost will likely build up on unheated surfaces in the winter.
(Score: 2) by Socrastotle on Saturday January 02 2021, @09:19PM
Owing to an axial tilt that is, oddly, near identical to ours - Mars also has a seasonal cycle nearly identical to ours. Summer near the equator on Mars reaches temperatures of around 70 degrees F. During the winter it obviously gets much colder. This has dramatic implications for all infrastructure. And, in the longrun, Mars will likely be terraformed.
But I mean really the most relevant reason is simply time keeping. Mars and Earth will rapidly grow apart. 40 million miles alone will do that just fine, but it's going to be especially radical in this case. Owing to 0.38G, we will already see the second generation of Martians having dramatic physical differences contrasted against humans (Earthlings?). And they may not even be physically able to ever return to Earth. Imagine you are a 180lb man and you moved to a place where you were suddenly, and permanently, 473 pounds. You'd likely just crumple to the ground. And it wouldn't just be physical discomfort - your organs, bones, and other physiological systems would experience a comparably radical and immediate change. Organ failure seems a probable outcome.
We will inevitably see Mars, and Martians, share less and less with Earthlings over time. Consequently, year 0 of Martian time will have meaning for Martians - whereas the Earth equivalent will gradually come to be seen as little more than an arbitrary conversion used only as necessary.
(Score: 5, Insightful) by kazzie on Thursday December 31 2020, @09:45AM (1 child)
Having gone to all the trouble to travel to Mars, I vote that all Martians get an extra 37 minutes in bed each morning.
(Score: 1, Funny) by Anonymous Coward on Thursday December 31 2020, @09:59AM
In reality I'd expect an extra 37 minutes for morning meetings 😈
(Score: 2) by PinkyGigglebrain on Thursday December 31 2020, @10:10AM (4 children)
WTF? when did that happen?
Humanity currently can't even get back to Luna, and yet we have "a decent shot at sending people to Mars"??
Talk to me when we have an actual working ship/lander, a real plan to get the people to Mars and back. and most important, keeps them alive in the process.
"Beware those who would deny you Knowledge, For in their hearts they dream themselves your Master."
(Score: 2) by fakefuck39 on Thursday December 31 2020, @12:29PM (3 children)
where have you been? we already sent an electric car with full self-driving capabilities for them to drive up there. we're ready to go. we even got a starship now flying regular missions just like the uss enterprise on star trek. the boring company is currently digging a long high-speed railgun tunnel on the moon to launch people to mars from there. the tunnel will be complete 2 years from now.
I think the issue is, you're getting your rss feed from the internet, and that news hasn't been updated in a long time. for current stories, you need the brain interface chip implanted like the rest of us.
go tusk.
(Score: 0) by Anonymous Coward on Thursday December 31 2020, @05:54PM (1 child)
Christ, what a shit spewing moron
(Score: 0) by Anonymous Coward on Thursday December 31 2020, @06:39PM
And (based on his previous posts), he's doing it from the shitter -- hiding out from his "beautiful wife" so she doesn't see his obsessive posting behavior...
(Score: 0) by Anonymous Coward on Thursday December 31 2020, @06:58PM
Damn you had me goin until the last line. I honest to god thought you were genuinely delusional.
(Score: 1, Insightful) by Anonymous Coward on Thursday December 31 2020, @10:12AM (10 children)
Do nearly everything by UTC. Use that for ages, dates, and so on. Earth defines seconds, minutes, hours, weeks, months, and years. There are legal and religious issues if this gets messed with.
In typical use, Mars defines the days. The clocks roll over from 24:36, not 23:59. Solar noon is 12:18:30 on Mars.
(Score: 2) by pkrasimirov on Thursday December 31 2020, @10:27AM (1 child)
The problem is it will misalign with Earth clocks.
(Score: 2, Insightful) by Anonymous Coward on Thursday December 31 2020, @11:54AM
The offset from UTC happens to change about once per day. Something like February 29th happens about every 48 days, with that calendar day just missing.
Alternately, you could make the UTC days be official, but use the 24:37 clock for ordinary stuff like scheduling a lunch break.
Something has to break. The least disruptive thing is to use a 24:37 clock for going about your day, and Earth UTC for everything else.
(Score: 1, Interesting) by Anonymous Coward on Thursday December 31 2020, @12:05PM
Why is that better than, say, adding a leap-minute-and-a-half to every hour? Why not just roll over the hour after x:60:29 instead of after x:59:59?
(Score: 2) by kazzie on Thursday December 31 2020, @02:29PM (3 children)
Or just use Universal Coordinated Time throughout the universe?
(Score: 3, Insightful) by hendrikboom on Thursday December 31 2020, @05:54PM (2 children)
Using UCT throughout the universe is practical only at those parts of the universe where simutaneity is approximately meaningful; i.e., those parts whose long-term average motion puts them in the same inertial reference frame.
Works for the objects orbiting out sun.
-- hendrik
(Score: 2) by kazzie on Thursday December 31 2020, @07:16PM (1 child)
Bu- bu- b-... they said it was universal!
(Score: 0) by Anonymous Coward on Friday January 01 2021, @04:14AM
Universal for all places ON EARTH.
Context is vital.
(Score: 2) by Immerman on Thursday December 31 2020, @05:38PM (2 children)
Really annoying having to go to work at a different time every day.
I imagine that behind the scenes, everything will use epoch time (number of seconds from a reference time) just like it does on Earth. UTC is just a common format to use when writing it for human consumption - and that only when (inter-)global portability is needed. For everyday use, UTC is terrible, virtually nobody sets their house clocks to UTC time.
Martians will use the length of Mars days and years to mark time, because that will be what's relevant to them.
Seconds, and to a lesser extent, minutes, and hours are embedded into a lot of common units and reference information, so I imagine they would continue to be used with the same size. I imagine the easiest solution for clocks would be to use military time counting from 00:00 to 24:36:22 instead of to 23:59:59. That would also keep the unintuitive "short hour" in the middle of the night when few people would have to deal with it. Any sort of AM/PM convention is likely to introduce ambiguity between independent colonies.
They'll need to devise their own 760-day calendar to reflect the local seasonal shifts (With a leap-year every 11th year). Months and weeks are where things get interesting, since those are pretty arbitrary. But given the high divisibility of a Martian year (760= 2*2*2*5*19) and probably high number of intellectuals colonizing, I'd bet on an arrangement designed to maximize the consistency and divisibility of smaller (and thus more commonly used) times: 19 months of 40 days each, with each month having five weeks of 8 days each. That also keeps months and weeks close enough to what people are used to that casual communication and thinking wont result in too much confusion. (I vote the extra day be allocated to a three-day weekend rather than a 6-day work week.)
For religious observances... if there's any religious edict to observe Earth-based anniversaries, you'll presumably observe them when they're happening on Earth, along with all the Earthling believers - at at semi-random times roughly twice per local year. I imagine they'd develop their own local-time secular holidays over time - probably starting with solstices (perhaps both a summer and winter version of Christmas?), equinoxes, Landing Day, and other momentous events.
Legally - it's unlikely any Earth country will have legal jurisdiction, so it probably won't matter. Even if it did, the only things I can thing of offhand that concern themselves with years and ages of majority, etc - which if you're enforcing Earth law, would presumably be measured in Earth time. And taxes on Earth-based income - in which case you pay them when they come due, which will be happening on Earth.
(Score: 2) by Immerman on Thursday December 31 2020, @06:28PM
Gah, wait, nevermind about the calendar, I accidentally used the synodic period rather than the siderial period.
There's 668.5991 sols (solar days) in a Martian year. 668 has prime factors 2*2*167, while 669 has prime factors of 3*223. Whatever calendar they come up with will likely be just as ugly as Earth's. Oh well.
(Score: 0) by Anonymous Coward on Friday January 01 2021, @04:10AM
Quoth the parent:
"I imagine that behind the scenes, everything will use epoch time (number of seconds from a reference time) just like it does on Earth. UTC is just a common format to use when writing it for human consumption..."
Wrong. UTC is more than a formatting standard. UTC attempts to keep time as measured by atomic clocks in sync with time as determined by the earth's rotation to within a certain error tolerance. This is why UTC inserts leap seconds when it becomes necessary.
The time standards you are looking for increase monotonically and at a steady rate as determined by atomic clocks--no leap seconds ever. Two standards to choose from are:
1/ International Atomic Time (TAI)
2/ GPS time
Each of these was in sync with UTC or its predecessor standard when they were created and have drifted slowly away from UTC over the years because they do not incorporate leap seconds ever.
(Score: 5, Interesting) by KritonK on Thursday December 31 2020, @01:04PM (3 children)
Robert L. Forward [wikipedia.org] addressed this issue in his novel Martian Rainbow.
In an appendix to the novel, he describes the Martian timekeeping system as one designed by scientists, for whom the duration of a second is sacred, and not by businessmen, who would have simply slowed down clocks, so that each sol would be exactly 24 Martian hours long, each consisting of 60 Martian minutes and 3600 Martian seconds. Instead, each sol is 24 Martian hours (maurs!) long, each maur is 60 Martian minutes (marmins!) long, but each marmin is either 61 or 62 second long, for a total of 3699 seconds per maur. There is also a 665-sol calendar year of 95 7-day weeks, with some additional off-calendar days (4 per Martian year (mear!), plus one extra, every 2.5 mears), to round up the mear to about 668.6 sols.
"You will have to put your Earth watches away and get a Mars watch."
(Score: 4, Insightful) by Immerman on Thursday December 31 2020, @06:20PM (2 children)
Given that virtually all the early colonists are likely to be scientists or engineers, and the length of a second is deeply embedded in almost all units, that seems unlikely to change. Plus, you'll want it to be easy to coordinate times with Earth, and Mars is likely to be only the first of many colonies throughout the solar system.
My money is on simply using epoch time behind the scenes for most things (seconds since a reference time), and military time with a "short hour" (24:00to 24:39:35) in the middle of the night, when almost nobody has to deal with it.
If they do want to have their own time that goes evenly into a day, I really doubt they'd stick with the ridiculous historical Earth conventions, they'd probably go with metric time - likely something like 100 centisols (about 15 minutes) per day, that each have 1000 "mars seconds" - (about 1.13 seconds).
(Score: 0) by Anonymous Coward on Thursday December 31 2020, @07:32PM (1 child)
What's wrong with earth time? 24, 12, and 60 are all nice numbers with lots of divisors, easy to conceptualize. Nobody would ever use a metric time except nerd enthusiasts. Martian time will only be measured and used by scientists and whoever it is that will plan the launches and receptions. I'm not convinced that humans will ever live on the surface of Mars. If we figure out how to catch asteroids and mine them, we will definitely stick to stations.
(Score: 3, Insightful) by Immerman on Thursday December 31 2020, @10:30PM
What's right with Earth time? Who actually uses all those divisors? That all came from ocean navigation where time and geometry are interrelated. Probably the Babylonians with their base-60 geometry. For everyone else it's just a yardstick to measure time, and simple fractions aren't that important. It's not like you can cook half a cake in half the time, or get a job done anywhere close to exactly 3x faster just because you have 3x as many people working on it.
Meanwhile, scientists will all use the standard SI time based around seconds - those are the units used in all the reference books, and almost nothing they calculate cares about time of day. Changing to any other base unit of time would be a HUGE headache, requiring replacing virtually every other unit of measure as well, from Newtons to Volts to sieverts - all of them have seconds embedded in their definition.
"Martian Time" will only really be relevant for Martians scheduling their day, and is fundamentally incompatible with the second. If we don't actually colonize and have people living their whole lives there, then I'm betting we'll never use anything but military time with a clock that goes to 24:39. Why would you want to learn a whole new time system for a slightly different length of day when you'll be returning to Earth in a few years?
And if you're a colonist who wants to simplify local timekeeping, going metric is simple. You certainly don't want a situation where you have to remember to convert from Mars-seconds to Earth-seconds before any calculation, that's just begging for ugly mistakes to happen. And if it's metric, then you only need to remember one conversion factor to convert between sols and seconds to get to all other units - 88.78ks per sol is easy to remember. If you're using non-metric time then you also need to remember conversion factors between mars-minutes, mars-hours, mars-seconds, whether as separate values, or by explicitly including the factors of 60 and 24.
Basing local time on sols also makes good sense to in that it's an explicitly local time system that's readily adaptable to any off-Earth colony. Space stations, where time is arbitrary, are likely to use Earth-standard days. But planets, moons, etc. are all likely to want a time system that tells them where the sun is at.
(Score: 2) by looorg on Thursday December 31 2020, @01:30PM (6 children)
Really? 24h37m is not significantly longer then 24h on earth. Time will be synced to earth time anyway -- The Masters voice and all that. Until a time they are on their own and don't want anything to do with us it won't matter. Considering we have had mechanical devices to tell time now for quite some time this is a non-issue.
If the "year" on Mars is 687 earth days is irrelevant, as it is today. All it shows is that the orbit of Mars vs the Sun is greater. Which I gather would only be of relevance if Mars would have seasons which is more or less only relevant when it comes to agriculture outside which I don't see them doing on Mars anytime soon.
(Score: 4, Insightful) by HiThere on Thursday December 31 2020, @04:11PM (1 child)
Sorry, but while over the period of one day an extra 37 minutes doesn't matter, those add up over time. If there's any important external activity at all the Mars day will need to dominate.
My guess is that everyone will have two clocks. One synced to some Earth time or other, the other synced to the Mars day. Since the same Mars time will never appear twice during the same Earth day period, the Mars time will dominate, but dates, etc. will use Earth time. The combination Mars-time-of-day + Earth-date will uniquely identify any point in time. The only problem is that it's possible to specify combinations that don't exist, but a (relatively) simple computer program could check for that.
Javascript is what you use to allow unknown third parties to run software you have no idea about on your computer.
(Score: 2) by kazzie on Thursday December 31 2020, @07:19PM
Or they could use the Bristol [thelog.org.uk] approach...
(Score: 2) by jmorris on Thursday December 31 2020, @05:31PM
Nah, other than close conjunctions, the radio delay is long enough that communication will be email only. Perhaps with video, but still more like mail than phone. Nobody will expect prompt replies because of the drift in day night cycles.
The second has to be held constant or everything breaks. Mars is a lucky break with the day being close. Means minutes and hours can stay constant too. Clocks there will just run past midnight and roll over at 24:38, no real problem. Keeping the week would also work. Timekeeping beyond that, a replacement for months, quarters, years, will be where the fisticuffs begin since there are no obviously correct answers and everyone will have a pet idea.
Even better is people will be keenly aware that any proposed solution really needs to scale. By the time we have enough Martians to bother rewriting all the timekeeping libraries we will also have Lunatics and soon be planting colonies on worlds with very different natural time cycles. Some will be strange enough to simply ignore the local cycles and just keep UTC (asteroids), others will have usable day/night cycles, seasons, etc. that it will be useful to adapt to. Is there a universal solution even possible?
Since the second will almost certainly be held constant everywhere, the timestamp will also remain constant. Number of seconds past Jan 1, 1970 UTC on Earth will remain the base even after we are on worlds around other stars. Converting those timestamps to a local time will be even more fun than the current timezone + internationalization libraries. Relativistic effects will eventually need to be taken into account. Just printing the time will invoke hairy floating point math libraries.
(Score: 0) by Anonymous Coward on Thursday December 31 2020, @06:52PM (1 child)
Time may be synced to Earth time, but the lag makes some things problematic.
Imagine managing your investments with that variable lag--no high speed trading on the big Earth stock exchanges for Martians. I could see forward-looking money managers going for this business, "We'll manage your fortune for you, while you are hours behind the action."
Come to think of it, at least some of the early Martians will probably be the super rich that buy their way onto the rocket. But once they realize they will be behind/lagging their trading competitors, perhaps that will dissuade them from the trip after all?
(Score: 0) by Anonymous Coward on Thursday December 31 2020, @07:51PM
They'll just convert their investments - buy a load of luxury goods or spices to transport.
(Score: 2) by Immerman on Thursday December 31 2020, @11:02PM
If you were on a space station where time is arbitrary, absolutely. Not much point in syncing to anything else.
On a planet though it'd be silly to sync to Earth time - all your operations, available solar power, etc. will be synced to the local solar day.
You'll still want to use standard seconds for measuring time intervals for any sort of calculation purposes - anything else completely breaks the entire system of measures, since seconds are embedded in the definition of virtually every other unit. And quite possibly you'd just use military time counting to 24:37 instead of 24:00 - that'd certainly be the easiest solution.
The only other option that makes sense to me is to add a supplemental time-of-day clock based on solar days - probably metric since that lets you easily convert from any scale of time measurement to standard seconds with only a single conversion factor. Clocks would likely count in centi-sols since that dives you a nice fine-grained day with two digits and no decimals, with a4-digit [00.00] clock counting in roughly [15 minute.11 second] intervals. High noon is at 50.00, and the standard "8-to-5" workday would instead be 34-to-70.
(Score: 2, Insightful) by Anonymous Coward on Thursday December 31 2020, @02:04PM (16 children)
The martians will never see sun, they'll be living underground in habitats. They'll use earth time, and set the lights however they want to.
(Score: 0) by Anonymous Coward on Thursday December 31 2020, @03:38PM
Bbbut... how will we get crapola-fest articles about the minutia of Mars life to get us on board with the next $10T budget request to develop biro pens and velcro strips that work ON MARS TADA!?
(Score: 0) by Anonymous Coward on Thursday December 31 2020, @03:43PM
On Mars, finally, a group of 15 people who *will* eat bugs. The mission of the globalist NGOs will be declared a success.
(Score: 2) by mhajicek on Thursday December 31 2020, @05:29PM
Even living underground, any power intensive work will be scheduled for when the sun is shining.
The spacelike surfaces of time foliations can have a cusp at the surface of discontinuity. - P. Hajicek
(Score: 4, Interesting) by istartedi on Thursday December 31 2020, @06:09PM (10 children)
At Martian temperatures, we may already have superconductor materials that could be used to maintain a magnetic field strong enough to curb the charged particles that comprise much of the radiation. That field might interfere with other equipment, but it could be used around a solarium and/or greenhouse so the residents don't have to be mole people. So you'd sleep underground and lights would be your signal to wake up, but if you wanted to "step outside" you'd just walk down the access tunnel to the solarium to watch the sunset, dust storms, whatever is going on.
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(Score: 0) by Anonymous Coward on Thursday December 31 2020, @06:36PM (8 children)
There would be no point. The sun won't be strong enough for vitamin D synthesis or photosynthesis in plants. They will live underground, because it's the only sane way to operate.
(Score: 2) by Immerman on Thursday December 31 2020, @06:57PM (7 children)
Sure it will. 40% as much sun reaches Mars' orbit as Earth's. And at the surface it's closer to 6%, since Earth's atmosphere blocks a lot of it here.
That's a bit of an overcast day, but still plenty for growing plants and making Vitamin D. It just won't happen quite as fast as on Earth. In fact there's a LOT of partial-sun and shade-loving plants that would still be getting a more sun than they'd really like.
And a few meters of glass or transparent ice would provide just as much radiation protection and atmospheric compression as a few meters of rock.
(Score: 2) by Immerman on Thursday December 31 2020, @07:00PM
Whoops, typo. That should be
> at the surface it's closer to 60%
(Score: 0) by Anonymous Coward on Thursday December 31 2020, @07:46PM (5 children)
Much of the northern hemisphere doesn't get vitamin D from the sun half the year. How are they going to do it with 60% strength, probably close to the Martian pole for water access? How are you going to grow enough food to feed people with 60% strength sunlight? They'll live underground or on a station, and they will eat engineered foods grown from cultures. Energy will be nuclear.
(Score: 2) by Immerman on Thursday December 31 2020, @09:38PM (4 children)
>Much of the northern hemisphere doesn't get vitamin D from the sun half the year.
The problem is not lack of sun, it's the fact that they're spending their time indoors or bundled up in warm clothes that block the sun. It only takes about 10-30 minutes several times a week to make enough vitamin D. Doubling that in a colony with a climate-controlled "outdoors" is not going to be a problem.
>How are you going to grow enough food to feed people with 60% strength sunlight?
Easy, use 167% as much farmland, so that the total solar energy intake is the same. Or use crops that don't waste most of the energy. Look at wheat and corn - we grow an entire huge plant to get maybe a few handfuls of grain.
And in that vein, I think you're not far wrong with cultures - algae, bacteria, etc. are radically more efficient crops, regardless of where you're getting your energy. And for staple ingredients like flour, sugar, oil, and protein powder, that are liquid or powdered anyway, there's really no benefit to getting it from a large plants.
(Score: 0) by Anonymous Coward on Friday January 01 2021, @02:54AM (3 children)
Martian soil is loaded with perchlorates, can't grow in farmland, you need to build dirt just for agriculture. I don't have time to find the data, but if I remember I will be back on vitamin D. At the very least, I'm incredibly skeptical of the idea that humans on Mars will ever try to get "natural" sun, use the sun to grow plants, or rely on solar power. It's silly to go through such expense and risk in a hostile environment.
(Score: 2) by Immerman on Friday January 01 2021, @03:59AM (2 children)
>Martian soil is loaded with perchlorates, can't grow in farmland,you need to build dirt just for agriculture.
True - but it's not terribly hard to remove perchlorates, and you can't grow stuff outside anyway, what with all the vacuum and mostly subfreezing temperatures. And when you make dirt once, you get to use it year after year. In fact, with responsible agriculture you end each growing season with more dirt than you started with, since it's mostly organic material. Or, you forgo the dirt altogether and use hydroponics or aeropoics. And those challenges will be the same regardless of where you're getting your light from.
.
As for light - solar cell efficiency is in the 10-25% range, and if you're making the solar panels locally they'll probably be at the low end for a long time to come. Which means that using artificial light will require solar fields between 4x and 10x as large as your farmland to generate the same amount of artificial light as windows would let in.
As for the expense and risk - depending on the available raw materials, making glass is relatively cheap - just melt "clean" sand and cast it. Making clear ice is even cheaper. Far cheaper than making solar panels, at least early on. If you just care about the light rather than a view, you don't even need super large or thick windows, just use thin, cheap, mirrors to concentrate light and bounce it around the thick wall that's blocking radiation.
There's also some incredible potential for microbial crops - one of the fun things with biotechnology, especially with microbes that reproduce (and thus evolve) so quickly, is that if you can create a gentle path to the environment you want them to survive, evolution can often rapidly do the hard work for you like magic. Much as wild bacteria evolved to survive 1000x the lethal dose of antibiotics within 10 days in that Harvard demonstration ( https://www.youtube.com/watch?v=plVk4NVIUh8 [youtube.com] ), so too could "crop" microbes rapidly evolve to handle something closer to native Martian conditions.
It's speculated that just spreading a large sheet of plastic on the ground would trap enough heat, moisture, and atmospheric pressure to allow microbes to thrive on the surface, provided you cleaned the toxins from the soil first. Radiation isn't really a problem for most single-celled organisms, since any damaged cell will just die and make more room for its neighbors to expand. Make a similar "petri dish" the size of a football field, with a gradient from ideal to native soil conditions beneath the plastic sheet, and that field might well be fully green before you know it.
(Score: 0) by Anonymous Coward on Sunday January 03 2021, @12:22AM (1 child)
When the soil, pressure, temperature, and maybe even the gravity is wrong, they might as well be on a space station instead. That way you're not stuck in a gravity well of a planet.
(Score: 2) by Immerman on Sunday January 03 2021, @08:50PM
Once you get off Earth, nowhere is ideal. And there's much to be said for space stations, especially if you assume they're built inside a thick shell of asteroid "concrete" for shielding.
However, most of the challenges are the same for both space stations and planetary colonies - you're building a habitat and ecosystem from raw elemental materials, you've got lethal vacuum outside, and dust from the material you're working with outside is likely to be extremely unhealthy if it gets inside.
The big unanswered question is whether gravity on Mars is enough to keep people healthy throughout their lifecycle or not. If not, that greatly increases the difficulty of colonizing Mars to the point that it's probably not worth doing.
If gravity is the gravity is sufficient though, then it offers a huge advantage in long-term habitat durability:
-In a rotating space station you've got both air pressure and centrifugal force trying to rip your habitat apart, and any tensile failure in the skin is likely to be catastrophic.
-On a planet you can just bury your habitat underground, covered in a bit more than 15psie of sand, concrete, or whatever shielding you're using, and you'll put almost the entire habitat under compression. Fill the habitat with air, and that air will support most of the weight of the shielding on the roof. Which means that the entire outer skin of your habitat is under almost no net structural load. All you need to worry about is air leaking through the walls, not the walls themselves coming apart.
As a further advantage, building things to support compressive loads tends to be a *lot* cheaper and easier than tensile loads - in many situations you can literally just pile up dirt to support a compressive load. It's the difference between the loads trying to mush things together, and trying to tear them apart.
There's also a big psychological/aesthetic advantage to Mars - there's something outside. You've got blue sky that stretches as far as the eye can see, and vast landscapes giving the view a sense of scale. In a space station your perceptual universe is limited to the station itself, and whatever infrastructure you've built outside. Everything else - even asteroids passing nearby within the Belt, is too far away to be visible as more than a distanceless point of light. You may know intellectually that space is vast - but as far as your senses can tell it could just as easily be a featureless black sphere covered in lights, a few miles across.
Oh, and on Mars that sky is more than just a pretty picture - it provides a virtually unlimited supply of oxygen and carbon wherever you're at, if you have the relatively compact hardware to harvest it. Water too - in much smaller quantities, but enough to keep someone alive.
(Score: 2) by Immerman on Thursday December 31 2020, @06:51PM
Unless you're talking LHC-class magentic field intensity, you're not going deflect cosmic rays much.
But there's no reason for anything high tech - you could just use glass a few meters thick. To get similar radiation shielding as Earth's atmosphere provides, you just need a similar amount of material above you. Doesn't matter if that 1000kg/m^2 is provided by km of air, or meters of glass. You could even use the weight to counteract the air pressure within the habitat, allowing it to be built in moderate compression rather than extreme tension, which conveniently greatly increases the long-term durability.
Of course, the glass would likely start looking like a particle collider bubble chamber after a while - which could be beautiful for a while, but would eventually start really interfering with the view, and even the amount of light getting in. So you'd probably want to design it so that individual segments could be easily replaced. Or perhaps build it from ice so you could occasionally thaw and carefully re-freeze it back into transparency.
(Score: 2) by mrchew1982 on Thursday December 31 2020, @06:38PM (1 child)
Some of the latest habitat designs utilize thick water ice comes to nullify ionizing radiation. The whole colony won't have natural sunlight, but some will.
(Score: 2) by Immerman on Thursday December 31 2020, @07:12PM
Honestly, why not most/all of it?
A few meters of ice or glass not only lets in natural light while blocking radiation, its weight can also be used to keep your atmosphere compressed (and conversely, your atmospheric pressure can be used to hold the roof up), just like burying it/building underground would do.
If you're digging your habitats significantly underground natural light is definitely a major project. But near the surface, especially if you're building-and-burying, it's just a matter of installing thick glass blocks wherever you want a window.
(Score: 2, Insightful) by Anonymous Coward on Thursday December 31 2020, @04:30PM (1 child)
Yes and no. Mars and Earth have different gravity potential, plus they are in different position in the Sun's gravity well. General relativity predicts clocks on the two planets will drift with respect to each other. Locally the second will be the same but from a distance, it's not.
(Score: 2) by Immerman on Thursday December 31 2020, @09:42PM
Heck, it varies across the surface of the Earth -your clock will run slightly faster on a mountain-top than at sea level.
The difference though is barely enough to be picked up by the most sensitive atomic clocks, so it's not really relevant to much of anything.
(Score: 0) by Anonymous Coward on Thursday December 31 2020, @06:28PM
Cuz I'm gonna blow up 1/2 of the Earth, and rule the other 1/2. Neener-neener.