Martian Rainbow
Page 34
CLOCK AND CALENDAR
The Martian clock and calendar are significantly different than the Earth clock and calendar, although we tried to keep things as much like home as possible. Fortunately for those that have strong body rhythms, the Martian day is nearly the same as the Earth day, so you shouldn't lose any sleep over the shift in planets. But the extra 39.5 minutes is enough different that it causes problems. If Mars had been colonized by businessmen, we would have just slowed our watches down by 3% and continued using sols with 24 hours, hours with 60 minutes, and minutes with 60 seconds. The only difference would have been that the second on Mars would have been 3% longer than the second on Earth.
Unfortunately, this is heresy to a scientist. A second is no longer 1/86,400th of an Earth day, but is defined as the duration of 9,192,631,770 cycles of a certain frequency of radio waves from a cesium atomic clock. Since Mars was colonized first by scientists, we are stuck with the system that they developed, where a Martian second is exactly equal to an Earth second, so the scientists on the two planets can talk straight to each other. You will have to put your Earth watches away and get a Mars watch.
The Martian day is called a sol. The Martian sol is divided into 24 increments called maurs (for Martian hours). [Despite some snide comments by erstwhile friends, the maur is not named after me.] Each maur is roughly the length of an Earth hour so students still have one hour class periods and people still work eight hour shifts, only now they are eight maur shifts.
Now comes the real difference. Instead of a maur being made of 60 minutes of 60 seconds each for a total of 3600 seconds per hour, there are 60 marmins (Martian minutes, of course) of either 61 or 62 seconds each (remember a Martian second is identical to an Earth second). The shorter marmins are the 00 and 01 marmins in each maur and every marmin is divisible by 3, for a total of 21x61 +39x62 = 3699 seconds per maur. Then, three sols out of four, the 02 marmin of the 00 maur has only 61 seconds to give 3698 seconds for that maur and a total of 88775 seconds for the sol. The fourth sol does not skip that leap second and is 88776 seconds long. This gives an average for the four sols of 88775.25 seconds, close enough to the physical sol that the difference over a Martian year can be included in the leap seconds the scientists add or subtract occasionally anyway to adjust for the slowdown in the planet's spin rate and changes in the shape of its orbit. Fortunately, you don't have to worry about memorizing where the leap seconds go or don't go, all the leap seconds are programmed into the timing circuit of your digital Marswatch, along with the various holisols and leap sols to keep the yearly calendar on track with the seasons.
Another major difference between timekeeping on Mars and on Earth is that, because of the greater distance of Mars from the Sun, the Martian year (called a mear) is nearly twice as long as an Earth year. Because we have no slow-moving moon to make "moonths" important, we have done away with them. But we have kept the 7-sol week. (T.G.I.F. means the same thing on Mars as it does on Earth.) A Martian calendar year consists of 95 weeks of 7 sols each for a total of 665 sols.
To round the calendar up to the nearly 669 sols of the physical mear, we add four seasonal "holisols" outside the weekly calendar as near the physical equinoxes and solstices as possible. They are: the perisolstice, the apequinox, the apsolstice, and the periequinox. The following sol starts a new week, so is always a Sunsol. Thus everybody gets two sols off in a row.
The mear is really about 668.6 sols long, so every 2.5 mears, starting from M001.25 or the apequinox of M001, we have either a "springmear" and spring forward over the periequinox into the new week, or a "fallmear" and let the apequinox fall off the calendar, so the start of each new mear stays on track with the seasons. That should keep us on track until way past M999 (about A.D. 4000) when everyone will have to buy a new watch anyway.
The 95 weeks are divided into seasons. The seasons are not equal in length because of the high eccentricity of the orbit of Mars. Since the main human habitation here on Mars is now in the southern hemisphere, we designate the seasons by what is happening here. Those that live "Up Over" have the opposite seasons, of course. The year starts with the perisolstice, the solstice that occurs when Mars is close to the sun. This starts the short, hot summer in the southern hemisphere and the short, warm winter in the northern hemisphere. This southern summer season is 22 weeks long. There follows the apequinox and a 27-week fall, the apsolstice and a 26-week winter, and then, as Mars starts back in toward the Sun, is the periequinox followed by the shortest season of all, the 20-week spring.
The seasons are not used in writing down dates. The standard order for a date is a letter M to indicate that it is a Martian date, immediately followed by the number of the mear, with MOO0 coinciding with the Earth year 2000, when the starting times of the Earth year and the Mars year were very close. (They weren't perfect, but let the scientists worry about those little details.) Then comes the number of the week from 00 to 95, the three letter code for the sol of the week (SUN, MON, TUE, WED, THU, FRI, SAT), the maur, the marmin, and the second. If the date happens to fall on a holisol, the five letter abbreviations PSOLS, AEQUI, ASOLS, and PE-QUI, are used instead of the week and sol. In this nomenclature, the start of the mear is M025/PSOLS/ 00:00:00, while the last second of the mear is M025/ 95SAT/23:59:62.
MONEY
We do have money on Mars, although there are no bills. Bills wear out too fast, so we use coins of hardened anodized aluminum. The diameter and thickness of the coins are proportional to the value of the coin, while the colors of the coins follow the colors of the rainbow. Around the picture on the front of the coin are the words: Territory of Mars. There is no date, since there are no plans to make any changes, and we want to actively discourage collectors.
VALUE
THICKNESS
DIAMETER
COLOR
FRONT
BACK
(M$)
(mm)
(cm)
PICTURE
INSCRIPTION
0.01
1.0
1.0
Red
Deimos
1 Cent
0.10
1.5
1.5
Orange
Phobos
10 Cents
1
2.0
2.0
Yellow
Viking
One Dollar
10
2.5
2.5
Green
Olympus
Ten Dollars
100
3.0
3.0
Blue
North Pole
100 Dollars
There are no plans for larger denomination coins, since transactions that large should be carried out by iris-certified bank account computer transfers anyway.
The artificially low (and subsidized) exchange rate of one Mars dollar equalling one hundred U.S. dollars that was set up by the founding fathers before Alexander the Unifier brought Earth under one rule, has fluctuated wildly depending upon the diplomatic relations (or lack of them) between Earth and Mars. Now that The Unifier has allowed self-government again on
Earth, things have stabilized and the present rate is one Mars dollar equals 280 Earth credits.
A helpful hint for those caught without a ruler but having a pocket full of change: A stack of five vikings or a red on edge is one centimeter, while an oly is close to an inch across.
ATMOSPHERE
The original atmosphere of Mars when the Viking spacecraft first landed was significantly different than what it is now after the Lineups processed the polar ice caps and raised the temperature and pressure. The total pressure was only about 8 millibars, compared to about 1000 millibars (that's 1 bar) for Earth, and the 500 millibars at the bottom of Dugout Crater. The triple point pressure for water is 6.1 millibars, so any open water on Viking's Mars would not only have been frozen, it would have been sublimated away. If you had gone out for a walk back then without your space sui
t, you would have found yourself a little short of breath, and pretty soon you too would be frozen and sublimating away.
Not only wasn't there enough air to breathe, what little there was wasn't worth breathing. The atmosphere consisted of 95% carbon dioxide, 3% nitrogen, and 1.5% argon, with oxygen only 0.1%. The water vapor content was variable, from nearly zero in the winter to 3% in the summer. This is to be compared to what you were used to back on Earth, which was 78% nitrogen, 21% oxygen, 0.9% argon, and only 0.03% carbon dioxide; then, depending upon the humidity, the water vapor in the air would be from 0 to 3%, displacing the other gases.
The atmosphere down at the bottom of Dugout Crater is certainly not earthlike, but it is better than what we started with. It contains 48% oxygen, 35% carbon dioxide, 13% nitrogen, 3.5% methane, and trace amounts of argon and ammonia. The argon came from the original Martian atmosphere, while the methane and ammonia were deliberately put in when the Lineups processed the poles. The methane and ammonia make it smelly, but they are good greenhouse gases and help keep us and our crops warm down at the bottom of Dugout Crater.
The partial pressure of each of the major components of the atmosphere changes with altitude in a slightly different manner, with the heavier gases, like carbon dioxide, falling off faster with altitude than the lighter gases like methane and ammonia. That means these greenhouse gases form a higher percentage of the atmosphere at high altitude, where they can do the most good. The following table gives the partial and total pressure with altitude. Take a good look at it before you start on a trip.
The temperatures given are the average daily temperatures in the midsouthern latitudes for summertime in the south. They can vary ±20 degrees C during the sol. Fortunately, the Lineups warmed things up somewhat from the original Martian temperatures when they processed the ice caps, and the increased pressure and the greenhouse gases are continuing to warm things up.
The amount of water vapor pressure given in the table is the maximum for 100% humidity. Usually, however, the only time you run into 100% humidity is down around Splash Lake on a hot, muggy summer sol, but that is soon relieved by a thunderstorm.
(Normally, a guidebook like this would also give you another table based on the average winter temperatures, but you shouldn't be traveling when it is winter in the southern hemisphere.)
ATMOSPHERIC PRESSURE WITH ALTITUDE
AVG. SUMMER
MAX
PARTIAL PRESSURE
ALT.
TYP. PLACE
TEMPERATURE
H2O
O2
CO2
N2
CH4
NH3
Tot
(km)
(°K)
(°C)
(°F)
(mb)
(mb)
(mb)
(mb)
(mb)
(mb)
(mb)
+ 27
Peaks
186
-87
-125
0
15
4
6
4
0.1
29
+ 10
Tharsis
237
-36
-33
0
66
30
21
7
0.1
123
+ 5
Elysium
252
-21
-6
1
89
46
28
8
0.1
171
+ 2.5
Melas, Olym.
260
-13
9
2
104
56
32
9
0.2
201
0
"Sea" level
267
-3
27
3
119
68
36
10
0.2
236
-2
Lowlands
273
0
32
6
132
79
39
11
0.2
261
-4
Hellas Basin
279
6
43
10
146
90
43
11
0.2
290
-10
Halfway Ter.
303
30
86
42
191
130
55
13
0.3
389
-14
Augustus
319
46
115
100
224
161
63
14
0.3
462
-16
Splash Lake
327
54
129
150
240
178
67
14
0.3
499
As can be seen from the table, the total atmospheric pressure at the bottom of Dugout Crater is 500 millibars and exceeds 290 millibars for a few hundred kilometers' distance around Dugout at the bottom of Hellas Basin where the altitude is below -4 km. These pressures are high enough that you don't need a pressure suit outside.
You can put on a pressure suit if you want (and you must if you leave Hellas Basin), but in the basin and especially down in Dugout, all you will need is your Turner Turbomask with its miraculous molecular microfilter. A battery-powered turbofan sucks in the low-pressure outside atmosphere with its 48% oxygen, 35% carbon dioxide, and 13% nitrogen plus other noxious and smelly stuff at 500 millibars and creates some 3 atmospheres (3000 millibars) on the high-pressure side of the filter. The magical molecular microfilter passes nitrogen and oxygen through to the other side and prevents the carbon dioxide and smelly stuff from getting through. You get to breathe the filtered air on the other side through your mask. The turbomask delivers 58% nitrogen and 42% oxygen at a little over 500 millibars, giving you the same amount of oxygen per breath as Earth's 1000 millibar atmosphere with 21% oxygen. A slight bit of excess pressure inside the mask not only makes it easier to breathe, but helps keep the nasty stuff out.
Up at Breakout, where Getout Slope merges with the bottom of Hellas Basin at -4 km altitude and the total pressure is only 290 millibars, the turbomask is delivering a 72/28 oxygen-to-nitrogen ratio, or 210 millibars of oxygen and 80 millibars of nitrogen. This is roughly the same mixture that was used in the first American SpaceLab in the early space exploration days.
In an emergency, it is possible to use a Turner Turbomask (set on pure oxygen) for your air supply and your skin as your space suit up to about 2.5 km altitude, where the total air pressure has dropped to about 200 millibars. Don't stay outside too long, or the surface of your skin will be one large hickey.
Now ... if you are new to Mars, and the last time your body experienced the effects of too much carbon dioxide was back on Earth when you chug-a-lugged a warm cola and experienced a painful burp ... then widen those scanners and put the next section into permanent memory.
CARBON DIOXIDE POISONING
Carbon dioxide can kill you.
I repeat ... CARBON DIOXIDE CAN KILL YOU!!! It can get you two ways. First, it can displace the oxygen you need and suffocate you to death. Second, even if it can't get you that way, it will sneak up on you and poison you to death.
Most of the medical information on the dangers of carbon dioxide poisoning was obtained back on Earth when workers went in to clean out the vats in breweries. Exposure to high concentrations, such as 25% of an
Earth atmosphere (partial pressure of 250 millibars), causes convulsions and coma within one minute. Exposure to concentrations near 10% (100 millibars) for only a few minutes will produce coma and subsequent asphyxiation. Since the partial pressure of carbon dioxide at the bottom of Dugout Crater is 178 millibars and at the top is 90 millibars, you can see what just a few minutes of breathing without a mask can do to you.
Inhalation of concentrations from 7 to 10% (70 to 100 millibars) produces difficulty with breathing, headache, dizziness, and queasiness. Five percent produces shortness of breath and headache in many individuals. After several hours of exposure to just 2% (20 millibars), most people develop headaches and have difficulty breathing after only mild exertion. So if you have a headache, or have difficulty breathing, or otherwise don't feel well, immediately suspect a leaky mask combined with a faulty CO2 warning system.
What is happening to you is not a lack of oxygen. Instead, the carbon dioxide (called carbonic acid gas on the label of your cola can back on Earth) is building up in your bloodstream, slowly turning your blood into carbonated vampire beverage and lousing up your delicate internal pH balance.
So—keep those breathing masks on tight and make sure that every breath you take has come through the filter canister on your turboexchanger. If your mask is not on tight, you may be getting enough oxygen to breathe and feel all right, but at the same time you may be getting too much carbon dioxide. Before you know it, you will be confused, weak, sick, or go into convulsions from acid blood.
When you are in an air-filtered building or work compound with the 40/60 oxygen/nitrogen ratio that makes exercise at 500 millibars possible, and even fun (according to some—never could see it myself), keep your turbomask or an emergency oxy-mask on you at all times. (There are some indoor sports where it is allowable to keep your masks on the bedside table.) If the structure is breached, allowing the outside atmosphere in, get to a high point until you can get your emergency mask on.