of the Sun. The orbits of Mercury, Venus and Earth lie closer to the Sun than its orbit, while those of Jupiter, Saturn, Uranus, Neptune and Pluto lie outside of it.
Martian days and years:
"The orbit of Mars lies in a plane at an angle of 1 degree and 51 minutes of arc to the plane of the ecliptic, which means that Mars and the Earth rotate around the Sun almost in the same plane.
"Mars requires about 687 Earth days for a full revolution around the Sun, and this may be considered as a Martian year.
"Mars rotates around its own axis once in every 24 hours, 37 minutes and 22.7 seconds, making the Martian day only slightly longer than the Earth day, so that the Martian year has 569.6 Martian days.
Seasons of mars:
"The rotational axis of Mars is inclined to the plane of its orbit by 24 degrees, which is very close to the inclination of the Earth's axis to her orbit, namely 23.5 degrees.
Diameter of mars:
"The diameter of Mars at the equator is 6,780 kilometers, while when measured along the polar axis, it is 35 kilometers shorter. This is a little more than half the diameter of Earth.
"The mean density of the planet is only 72% of that of the Earth. Its mass is proven to be approximately one tenth of that of the Earth, within close limits. These figures yield an acceleration due to gravity at the surface of Mars as equivalent to only 38% of that of
the Earth, or 0.38g.
Moons of mars:
"Mars has two very small moons, Phobos and Deimos. Phobos is very close to its
mother planet, its mean distance from the center of Mars being equivalent to only 2.77 radii of Mars. It circles the planet in 7 hours, 39 minutes and 14 seconds, doing so several times a day, somewhat similar to Lunetta circling the Earth. Viewed from the surface of Mars, it would rise in the west and set in the east.
Its
"The other moon, Deimos, lies at a distance from Mars of a scant 7 radii of the latter and requires about 30 hours and 18 minutes to encircle it. We estimate its diameter at 10 kilometers and its orbit is circular within close limits."
Atmophere of mars:
It is well proven that Mars has an atmosphere, although it'sconsiderably less dense than that of the Earth. Once in a while, the formation of clouds has been noted. As to the surface, its formations are very clearly shown, particularly in infrared photography. At times, however, these formations are covered by some sort of
diffuse white or yellow layer which registers particularly on ultraviolet photographs."Such layers must be considered cloud formations, and we take the white ones for water vapor and the yellow ones for sand clouds in all probability, whirled up by powerful storm conditions.
regular appearance of snowfalls in the polar regions in Winter, and the occasional
snowfalls in the temperate zones. There's no other possible explanation for regions of hundreds of thousands, or even millions, of square miles being concealed, sometimes in a
very brief period, by a blinding white layer. The borders of the polar snowcaps also are
frequently surrounded by a veil of clouds. We're inclined to interpret this veil as fog banks, developing over regions where snow is beginning to melt, rather than as clouds in
the conventional sense. These fog banks develop in the cold Martian nights. Generally
they are gone by noon."
"A mercury barometer at sea level on Earth reads 760 millimeters where a corresponding one on Mars would read only 64 millimeters, if we've estimated correctly.That's only one twelfth of the terrestrial atmospheric pressure at sea level.""Confound it! That means we'll have to wear pressure suits and employ artificial
respiration on Mars!"
"There's no doubt of it, Colonel. Surface atmospheric pressure will be equivalent to
that at 60,000 feet above the Earth. The pressure is higher at low altitudes because the lower we
descend, the heavier is the column of air above us. Now the acceleration of gravity on Mars is 38% of ours on Earth. So any column of Martian air of equivalent mass would press upon the air below it with only 38% of the weight with which it would do so upon Earth. Consequently increase in density of Martian air with diminishing altitude necessarily takes place more slowly that upon Earth."Putting it another way, we can say that decrease of barometric pressure with increasing altitude takes place more slowly than at home. The atmospheric pressure of the terrestrial atmosphere decreases by a power of ten for every 18 kilometers of altitude; that is to say that ground level pressure is reduced at 18 kilometers altitude to a tenth, at 36 kilometers to one ten thousandth of an atmosphere.But on Mars, the pressure decreases by a power of ten only every 47 kilometers by reason of the weaker field of gravity. So, if we have but a twelfth of our terrestrial pressure at the surface, we shall have one hundred and twentieth of that pressure at 47 kilometers, one
twelve hundredth at 94 kilometers..."
Presence of oxygen:
There's difference of opinion as to the oxygen content; some observers insisting that they have proved that it exists. But if,indeed, oxygen is actually present, the quantity is considerably less than on Earth, even percentage-wise."
"There isn't the slightest doubt that plant life exists, and the botanists consider it well
within the realm of credibility that Martian plants may live within a sort of 'internal
oxygen atmosphere.' A plant applies photosynthesis in order to live, and generates new oxygen in the process, although it does require a certain amount of oxygen for recycling.
If we assume that such a plant can store oxygen within its system, there's no reason why
it cannot do without any free oxygen in the surrounding atmosphere."Now as to animal life, the answer doesn't come quite so easily. Animals, in the ordinary sense of the word, cannot live without oxygen. Nature, however, discovers the most extraordinarily manifold methods of providing animals with oxygen, even on Earth.Fish, for example, attract oxygen from the water through their gills. Monocellular
organisms absorb oxygen through their exterior membranes, just as they do their food.Why shouldn't a Martian animal get its oxygen by eating plants which have stored oxygen
produced by photosynthesis? It would, of course, demand that the lungs be more intimately connected with the digestive organs than are our own...
"Should you think this hypothesis a little far-fetched, there are other plausible
explanations. Take, for example, the condition of symbiosis, which is quite familiar in
natural history. Here animals and plants are able to survive jointly under conditions which
would be fatal to either party alone. Corals, which are fauna rather than flora, are a case in
point. We know that the oxygen content of the water within an extensive bank of coral is
far too low to sustain life in the coral creatures inhabiting it. So Nature simply grows
oxygen-producing algae throughout the coral bank. Thus it's quite reasonable to assume
that Martian animals may live with oxygen-generating plants in some analogous symbiosis.
"We do have animals on Earth which require no oxygen at all to remain alive.
Intestinal parasites, such as tapeworms, are typical of this class. Instead of relying on the
chemical process of oxidation as do most other animals, they use fermentation to obtain
the energy essential for the maintenance of life. Fermentation is the dissociation of sugar
into alcohol and carbon dioxide, which is the process that transforms grape juice into wine
or champagne. Fermentation, like oxidation, generates heat. Intestinal parasites exist
amid a superfluity of sugar. They are beautifully protected against temperature variations
by the bodies of their hosts, so they live extremely contentedly by fermentation without
any oxygen whatsoever.
Water:
The huge zones of vegetation, particularly those in the southern hemisphere seem,or many and various reasons, to have been oceanic basins. The earlier astronomers even named them "Mare" because they thought that they were actually lakes. Today we know that open water bodies of any such size are unimaginable in view of the low atmospheric pressure of Mars - why, they'd evaporate in no time!"What happened to the prehistoric Martian oceans and lakes is in prospect for our own, incidentally. We can follow on Earth the long process of their shrinkage through the various geological ages, and even through the short span of human history. Rome, for example, was a sea-side town when the Republic flourished, but since then the ocean has receded and Rome lies many miles inland. We find fossilized fish in all sorts of places in the mountains and deserts of the southwest states of America. These leave no doubt thatlarge portions of the American continent were under water and only emerged by reason ofthe sinking of the oceans and inland lakes. The Great Salt Lake of Utah is a tiny remnantof the prehistoric Lake Bonneville, and even now its level is dropping at a rate which canbe measured year by year.
"Planetary water loss is irrevocable and pitiless. On one side, the water sinks into the
crevices of the solid crust. These crevices continue to gape open as long as the
incandescent interior is undergoing a cooling process and shrinking. On the other hand,
water evaporates into the air. This process becomes more rapid as the atmosphere is
dissipated and its pressure drops."
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