If the theory as outlined were correct it ought to be possible to make it more and more probable and at last prove it without a shadow of a doubt by making closer and closer observations. We have made it sound plausible by examining celestial bodies which are very far off--the nebulæ. Let us now proceed to make it sound much more reasonable--perhaps we may even be able to prove it absolutely by applying it to the observation of a body that is much nearer us--and therefore susceptible of much closer observation--than the nebulæ, and that is the planet Mars. When we bring the telescope to bear on Mars, the planet, especially its polar regions, is brought so near that Percival Lowell has even remarked that we know more of the Martian polar regions than we have hitherto known about our own earthly ones. We shall observe Mars in detail then, following our observations with a brief glance at Venus so that we may check up on what Mars shows us. Then we shall take the final step that proves our theory up to the hilt.
For there is a planet that we may inspect with even greater detail than we can inspect Mars--and
that is our own. With the knowledge gained from inspecting Mars we can read the answers to certain riddles of Polar exploration that have hitherto baffled both the scientists and the explorers who found the scientists' theories inadequate to guide them when they actually reached polar regions. We shall then have traversed the solar universe from the farthest nebula to the very ground under our own feet. If in that survey we find no facts that contradict our theory but numbers of facts which contradict every other theory; if those facts all line up and fit into our theory and ours alone; we shall rest satisfied that we have actually discovered the true structure of the bodies which revolve in space. And, knowing the structure of our earth truly for the first time, it is but a step to utilize our knowledge in ways undreamed of hitherto--but that is to anticipate.
Let us first attain a general idea of the planet Mars as it is revealed to us by the telescope and explained by the orthodox astronomers. For this Moulton is as good a guide as anyone. In his "Introduction to Astronomy" he gives all the necessary elementary knowledge of the planet. Its orbit is the next beyond that of the earth--the sun being the center, while the orbit of Venus is nearest to the earth on the inner side. Its mass and volume are considerably less than the earth--and it is this relative closeness to the earth in
position that has made Mars so favorite a location for those people who speculate on the possibility of life on other planets. For they argue that conditions on Mars should be very similar to conditions on the earth. Mars has two small satellites, much smaller and nearer than our moon, and the period of the rotation of the planet is about thirty-eight minutes longer than our own day of twenty-four hours. An-other similarity with the earth is that the inclination of the plane of the equator to the orbit of Mars is about 24 degrees, so that its days and seasons would be very much like those of the earth.
Fortunately for the astronomer who wishes to observe its surface Mars has very little atmosphere. The amount of atmosphere is calculated by noticing--through the aid of proper apparatus and calculations--the amount of light received by the planet and the amount reflected from it. The ratio between those two is called the albedo. Clouds reflect more light than earth surfaces do for the light is absorbed by the atmosphere in part before it reaches the surface and the light reflected from the surface is again subject to tribute by atmospheric absorption before it gets clear from the planet and so the small amount of light reflected from the surface of Mars shows us that it has but little atmosphere. Other observations support this the fact, for instance, that
when a star is hidden or "occulted" by Mars there is no gradual hiding due to a rare and then denser atmosphere intervening as the paths of Mars and the star cross, but a sudden blotting out of the star. We lay stress on this point here, for it is in apparent contradiction to the phenomena of the light from the polar caps of Mars--which the older astronomers thought were ice caps reflecting light through what must have been an atmosphere as the light certainly rose above the surface of the planet.
In appearance Mars is a reddish planet to the naked eye, but the telescope reveals a surface of variegated color. There are many dark patches in the surface and they are fixed--but at each pole is a large circular white cap which at its apparent maximum extends from 25 to 35 degrees from the pole and which diminishes in size in the spring season until it sometimes disappears totally. But the reader should not jump to the conclusion that that diminishing in spring indicates that the cap is composed of snow or ice. The astronomers themselves have begun to doubt that. For the cap does not diminish gradually as it would if it were gradually melting ice. It does it by sudden jumps--but we shall return to that in detail later on.
Moulton notes these facts, remarks that some of the appearances of the caps are such as to indicate
View of Mars, showing the circular white spot which is an entrance to this planet's interior, instead of the so-called polar ice cap, thus proving that Mars, the earth, and all other planetary bodies are hollow and contain a central sun. (Photographed by F. A. A. Talbott, Beighton, England.) For optical reasons all astronomical photographs are inverted.
that they might be snow, but he immediately adds that we cannot account for the warm climate that would be necessary to cause the melting of the caps if they really were of snow.
The next thing we notice on the surface of the planet is the so-called system of canals. These were first seen in 1877 by Schiaparelli who called them by the Italian word "canali" which meant not canals but channels. As they are from twenty to sixty miles wide it is obvious that the later English designation of canals is a little unfortunate, even though Professor Lowell thinks that they are artificial constructions. These channels extend along the arcs of immense circles, and measure in length from a few hundred up to four thousand miles. Often they intersect in dark so called "water-areas" or "lakes". Lowell claims that the junctions of the canals are always supplied with lakes and that there are no lakes except at the junctions of canals. In 1882 Schiaparelli discovered that many of the canals were double, two running parallel to each other at a distance apart of 200 to 400 miles. Later observations confirm this although the apparent doubling was found to depend on the season. But what the canals mean Moulton does not know. They may, he says, be due to some kind of vegetation, they may be due to optical illusion. "The doctors disagree," Moulton
admits. That the planet's outside surface is the abode of life, as held by Professor Lowell, has been questioned on the ground that it would be too cold to support life. But Moulton doubts if the planet is as cold as the application to its supposed conditions of certain mathematical formulæ would indicate. And how uncertain the scientists are on this point may be seen from the fact that some of them have thought the polar caps are of snow while others have thought they consisted of frozen carbon dioxide gas which only solidifies at 109 degrees Fahrenheit.
In his "Descriptive Astronomy" written six years later than the book we have just been referring to, in 1912, Moulton has no advance to record in knowledge of the planet. Again he points out that the small amount of water on the planet would render the polar ice cap theory untenable. And if there were water, he adds, it is not at all certain that it would be raised in clouds, transferred from one region to another, and precipitated as snow. Mars only receives from the sun less than half the amount of light and heat that the earth does, and so its temperature is much less than that at which snow would alternately form and melt, and to the suggestion that it is frozen carbon-dioxide that forms the polar cap, Mr. Moulton opposed the fact that carbon-dioxide in an atmosphere, by its absorptive power, tends to
produce a high mean temperature, and so would prevent any such phenomenon as the freezing of a gas at the poles. And so Moulton concludes:
"At the present time we are not, justified in drawing any positive conclusion about the meaning of the polar cap or the climatic condition of Mars."
Such is the general impression of Mars and our knowledge about it that is gained from elementary text-hooks and that was once held by all astronomers. But there are some curious facts that do not seem to have been noted by Moulton before he wrote these two books or if noted they did not seem to him to be important--and these facts are at once very important and easily explained in the light of the present theory. Let us, therefore, see what those writers have to say who deal more in detail with this one planet.
E. Walter Maunder, F. R. A. S., in his little book, "Are the Planets Inhabited?" goes into some details regarding the presence of water on the planet. He puts the question whether the so-called canals are artificial or natural formations. If they are artificial it would certainly seem as if some intelligent inhabitants had made them for a purpose, and as they wax and wane with the seasons it would seem as if Lowell were right when he claimed that what we saw when they waxed in the spring was the mass of vegetation
growing by means of their irrigation, while the drying up of the vegetation in the winter would signalize the fact that the water supply had given out. On the other hand if we found them to be not artificially created canals at all, then Lowell's theory of the utilization of water from the poles would be invalidated, and we would be left just where Moulton's two books left us--in sheer ignorance of the whole matter.
But Mr. Maunder has a lot to urge against Professor Lowell's theory. Mars, he tells us, is much more like the moon in its conditions than it is like the earth. After studying in detail the temperature of Mars, Mr. Maunder concludes:
"The size of Mars taught us that we have in it a planet with an atmosphere of but one half the density of that prevailing on the top of our highest mountain; the distance of Mars from the sun showed us that it may have a mean temperature close to that of freezing mercury. What chance would there be for life on a world the average condition of which would correspond to that of a terrestrial mountain top, ten miles high and in the heart of the polar regions? But Mars, in the telescope, does not look like a cold planet. As we look at it and note its bright color, the small extent of the white caps presumed to be snow, and the high latitudes in which the dark markings--presumed to be water or vegetation--are seen, it seems difficult to suppose that the mean temperature is lower than that of the earth.
In the summer, the white polar caps of Mars diminish to a far greater extent than the snow and ice caps of the Earth; indeed, one of the Martian caps has been known to disappear completely.
The contradiction between this calculated very low mean temperature and the observations he has just made, Mr. Maunder finds in the fact that the extremes of temperature are very great on Mars. The maximum temperature of the planet, he thinks, is above the freezing point of water, but normally the water on the planet is frozen: "Mars is essentially a frozen planet; and the extremes of cold experienced there, not only every year but every night, far transcend the bitterest extremes of our own polar regions."
For that reason, he says, it is very unlikely that there is any vegetation on Mars, except possibly some of the very lowest type. But here is a very interesting point regarding the patches that have been thought to be water:
"Some of the so-called seas may possibly be of the latter class (stretches of vegetation) but that there must be expanses of water on the planet is clear, for if there were no water surfaces there would be no evaporation; and if there were no evaporation, from whence would come the supply of moisture that builds up the winter pole cap?"
"But we thought astronomers had given up the idea that the polar caps could be proved to be of snow," the reader may exclaim.
Well, the quotation just given shows the confusion on the subject in the minds of the orthodox astronomers. For right after saying that, Mr. Maunder quotes Professor Newcomb as remarking:
"There is no evidence that snow like ours ever formed around the poles of Mars. It does not seem possible that any considerable fall of such snow could take place, nor is there any necessity of supposing actual snow or ice to account for the white caps."
But Professor Newcomb does not go as far as the reader is, perhaps, expecting him to go. For snow he only substitutes a hoar-frost formed of extremely fine particles of water vapor (how, in such a low temperature they came to be vaporized and brought to the pole before re-freezing, he does not say.) And after quoting that, Mr. Maunder himself says, a little later on, that Mars is always a frozen planet, frozen except on its mere surface when this is exposed to the full rays of the sun.
In other words the surface of the planet would be more or less uniformly bright if this were the case. Certainly hoar-frost at the poles would not be such a different surface from all the rest of the planet as to give us the characteristic appearance of the polar
caps; and those caps would never disappear by whole-sale bounds as they have been observed to do in actual fact.
No, the astronomers who try to theorize on the basis of polar snow caps are simply getting themselves into logical trouble.
In his book entitled "Mars", Lowell says, in presenting a map of what he thinks is the "ice cap" of the southern Martian pole:
"It will be seen from it how much farther advanced is our knowledge of the Martian south pole and the regions about it than is our knowledge of either of our own."
What a significant admission that is, and not so much out of date at the present time as most people imagine who have taken all their knowledge of our earthly poles at second hand and never examined into it.
An English astronomer, E. S. Grew, in his text book, "The Growth of a Planet," remarks that polar conditions on Earth and on Mars cannot be compared because the meteorological conditions are quite different in the two planets.
But supposing what we see can be explained only by conditions which are not meteorological? Then the two planets, perhaps, can be compared. It is because our theory points to something permanent in the structure of the planet as the explanation of polar phenomena, and not to mere meteorological
changes, that we can compare the two planets and show similar agencies at work on each of them, testifying to a structure which is the same in the one as in the other--and as in all others indeed.
But let us turn to an observation of Professor Lowell of the utmost value. On page 86 of his book, "Mars", Professor Lowell records:
"Meanwhile an interesting phenomenon occurred in the cap on June 7 (this was in 1894). On that morning at about a quarter to six (or, more precisely, on June 8, 1 hour, 17 minutes, G. M. T.), as I was watching the planet, I saw suddenly two points like stars flash out in the midst of the polar cap. Dazzlingly bright upon the duller white background of the snow, these stars shone for a few moments and then slowly disappeared. The seeing at the time was very good. It is at once evident that the other-world apparitions were--not the fabled signal lights of the Martian folk, but the glint of ice-slopes flashing for a moment earthward as the rotation of the planet turned the slope to the proper angle. . . . But though no intelligence lay behind the action of these lights they were none the less startling for being Nature's own flash-lights across one hundred million miles of space."
These star-like points had, however, been seen before, and Lowell goes on to check up his observations with those of others:
"Calculation showed the position of the star points
to be in longitude 280 degrees and 290 degrees, and in latitude 76 degrees south. At this place on the planet then there was a range of slopes sufficiently tilted to reflect the sun from their ice-clad sides. On comparing its position with Green's map of his observations upon the cape of (Madeira) in 1877, it appeared that this was the identical position of the spot where he had seen star-points then, and where Mitchell had seen them in 1846, to whom they had suggested the same conclusion. Green Christened them the 'Mitchell Mountains.' At the time both these observers saw them, they were detached from the rest of the cap. We shall see that they eventually became islands, just as Green saw them, and that the observation in June marked an earlier stage in their history."
Now it is important to note in the above exactly what was seen--far more important, to do that than to pass it over and listen to Lowell's ideas, merely, about what he saw. And the definite thing that Lowell plainly saw, and was astonished by, and specifically mentioned, was "two points like stars flash out in the midst of the polar cap."
And let us also note that Green saw, many years earlier, two spots and that Mitchell saw, as far back as 1846, something similar but with a difference--which we shall come to presently. But meanwhile let us see how inadequate is Professor Lowell's explanation of what he saw--so that we may keep distinct
the actual thing and the mere theory which was made up to account for it.
In the first place, Edward S. Morse, in his "Mars and Its Mystery", a book which warmly supports Lowell's theories about life on Mars, on page 138, tells of photographs taken by Professor Pickering of the polar regions of Mars in which a vast area of white appeared around the pole in the amazingly short space of twenty four hours. In that time an area nearly as large as the United States was visible as a white cap, and then it gradually disappeared.
And yet Professor Lowell asks us to believe--if this is really ice at the poles that it is so permanent that two very steep slopes--so steep as to reflect light direct to Earth--should keep their size and shape and positions from 1846, when Mitchell saw them, until the present day. And we remember, also, Professor Newcomb's explanation that there is no snow or ice at the Martian poles but only immensely fine hoar frost which could not possibly pile up into steep cliffs and reflect light to us in the way described. And even Professor Lowell himself, in his other book, "Mars as the Abode of Life," admits that it would be very hard to prove that the polar caps were composed of snow or hoar-frost, and that he could not have--to his satisfaction proved it if it had not been that around the polar area was to be seen a band of dark blue which he took to be water from the melting ice of the snow-cap (page 81). But
later on in the same book he speaks (page 140) of the well-known total disappearance of the one cap and the almost entire extinction of the other, showing how each summer melts what the winter had deposited, and that in both cases that is nearly the sum total of the cap.
But if both caps are thus depleted by each summer, how could a great ice cliff--again we ask the same question--remain since 1846 to reflect to us the light that Lowell saw?
No, there are too many contradictions there. Ice cliffs, if they formed in the polar regions of Mars, would form at so many different angles and in so many different relative positions that flashes would be constantly sent over to us: There would be a display as continuous as that of heliograph signaling. As a matter of fact, what Lowell really did see was a direct beam two direct beams at the same moment flashing from the central sun of Mars out through the aperture of the Martian pole does not the blue rim around that area to which Lowell has referred indicate the optical appearance of the reflecting surface of the planet gradually curving over to the interior so that at a certain part of the curve it begins to cease reflecting the light?--and the fact that it is not seen often simply shows that it is only when Mars is in a certain position with relation to the earth that we are able to penetrate the mouth of the polar opening and catch the direct beam.
That it was a direct beam of light that Lowell saw, and not mere reflection may easily be proved. He particularly said, in writing about his discovery, that the light from the Martian cap was yellow when it was viewed at night. What does that imply?
The reader can best answer after making a simple observation. Let him go out any night and look into a lighted window from a distance. The flood of light coming from the window will be yellow. The reader will also find that all artists paint lighted windows seen through the night as being yellow. We may go close up to the window and see that the source of the light is an incandescent electric light bulb which may be dazzlingly white and yet the light at a little distance is just as yellow as if the window were illuminated with yellow-flamed candles.
Also the reader may try something else. Let him, after looking at the window from a short distance, as we have suggested, move away to one side, so that he no longer looks directly into the window, but sees it from a very great angle. The light from the window will then be seen to extend out beyond the window to a certain extent.
We may now apply this to Mars. It proves that the light from the polar region of Mars is a direct
Views of Mars taken at the Yerkes observatory, Sept. 28, 1902, showing the white circle or so-called snow-cap, projected beyond the planet's surface, which precludes all possibility of its being snow or ice.
illuminant from within the planet, because that light, seen at night, is yellow. Any other sort of light, a reflection from a snowy surface, for instance, or a reflection from sand or mountain surfaces, would be white.
And if the reader will refer to our photograph of Mars above he will notice that the light from the polar openings extends in a spreading mist of luminosity of a very definite form which cannot be mistaken and which is obviously many miles above the surface of the planet. Now let the reader compare that with what he saw when he looked through the night at a lighted window at an angle it is the same sort of extension of light. So that again proves that the Martian light is coming from a direct source and illuminating the section of the Martian atmosphere just above the polar opening.
Mitchell, whom Lowell quotes in the above extract, has some very interesting points to make. He speaks of the brilliant light of the polar caps a light more brilliant than that of the other surfaces which are supposed to be covered with ice. Then comes his description of the beam of light which we hold to come direct from the central sun of Mars:
"On the evening of the 30th of August (1845), I observed, for the first time, a small bright spot, nearly or quite round, projecting out of the lower side of
the polar spot. In the early part of the evening the small bright spot seemed to be partly buried in, the large one. . . . . After the lapse of an hour or more, my attention was again directed to the planet, when I was astonished to find a manifest change in the position of the small bright spot. . . . . In the course of a few days the small spot gradually faded from the sight and was not seen at any subsequent observation."
It will be noticed that Lowell speaks as if what he saw was the same gleam and glint that Green saw, and the same thing that Mitchell saw. But if it were really a permanent ice-cliff, why did Lowell and Green see the two flashes and Mitchell one flash? And why did something so permanent that both Green and Lowell saw it many years apart, why did it prove so impermanent when Mitchell saw it? Why was it only one gleam then, and not two, and why did it fade away?
Obviously it was a gleam from the central sun of Mars that Mitchell saw, and the reason it faded was because cloudy weather gradually obscured the interior atmosphere of Mars. And when Green and Lowell saw it a small cloud had passed over the face of the interior sun and that broke the gleam into two projecting beams with this opacity between them,
so that to Lowell two separated parts of the area of the Martian sun were visible and each sent its rays of light direct into his telescope.
It is very interesting to read Lowell's account of these observations and to note how his observations all fit into one another and are accurate and how his explanations fail to account really for what he sees. In this same part of his book, "Mars", he speaks of a fellow observer, Mr. Douglass, who detected "rifts" in the cap--which sounds suspiciously as if this observer has seen clouds in the interior of the planet passing across the face of the polar opening. And Lowell adds, "On June 13 I noticed that behind the bright points the snow (he calls it) fell off shaded to this rift" which again sounds as if clouds were gathering near the bright spots. He continues:
"Bright spots continued to be seen at various points to the westward round the cap. . . . . Throughout these days the cap was wont to appear shaded on the terminator side."
The last sentence surely suggests that cloud formations were coming into the field of view and that wherever they thinned the bright spots from the central sun could be seen between them.
We may note, in passing, that Proctor, the English astronomer, also refers, in his "Other Worlds than Ours," to the brightness of the polar regions although
he does not have the correct explanation of it.
That more attention should be paid to this brightness of the polar regions of Mars, is emphasized by an English astronomer, W. E. Denning, who contributed to the English scientific periodical, Nature, an article on the physical appearance of the planet from observations made in 1886. He says:
"During the past few months the north polar cap of Mars has been very bright, sometimes offering a startling contrast to those regions of the surface more feebly reflective. . . These luminous regions of Mars require at least as much careful investigation as the darker parts, for it is probably in connection with them that physical changes (if at present operating on the planet's surface) may be definitely observed. In many previous drawings and descriptions of Mars, sufficient weight has not been accorded to these white spots."
Earlier writers, however, had noticed that the spots were brighter than the other surfaces of Mars, an astronomer, writing in the Scientific American Supplement as early as 1879, in effect, having made that observation. But this writer was not aware of the real nature of the light. In 1892 the celebrated English astronomer, J. Norman Lockyer, repeated in a periodical a number of observations he had made thirty years before and had then communicated to the Royal Astronomical Society of England. Here is a significant quotation:
"The snow-zone was at times so bright that, like the crescent of the young moon, it appeared to project beyond the planet's limb. This effect of irradiation was frequently visible; on one occasion the snow spot was observed to shine like a nebulous star when the planet itself was obscured by clouds, a phenomenon noticed by Messrs. Beer and Madler, recorded in their valuable work, 'Fragments sur les Corps Celestes.' The brightness, however, seemed to vary very considerably, and at times, especially when the snow zone was near its minimum, it was by no means the prominent object it generally is upon the planet's disc."
No one who reads the above in the light of our theory can fail to see how it fits into it. A snow cap would not reflect light with so much more vividness than the other surfaces of the planet, and only direct beams of light coming from a central sun could give that luminous effect above the surface of the planet and varying as the atmosphere in the interior or above it was clouded or clear. Had it been a mere ice cap there would not have been this luminosity and, in particular, there would have been no luminosity when the planet was covered with clouds as Lockyer says it was. Furthermore, that luminosity is precisely what our own aurora borealis would look like if our planet was viewed from a great distance. And the light is the same in both cases.
From that early date we jump to 1905 and find Percival Lowell again telling of a bright white "kernel" which he observed at the Southern end of the Martian north polar cap.
That, then, is the situation. All the evidence points to the fact that it is light, and direct light at that, that causes what we have called the Martian ice-caps but which we ought to call the Martian polar openings. But perhaps the reader is still not convinced. He may recall that the writers who treat this aspect of Mars, whether or not they believe in the "canals" seem to have no doubt of the fact that at the poles we have snow or ice. We have already pointed out some inconsistencies in this view. Here are some other considerations that help to dispel that idea, and then, by turning to the planet Venus, we shall demonstrate absolutely that the polar circles are not snow, or ice, or even hoar-frost caps, but simply apertures leading to the inner and illuminated surface of the planet.
A writer, evidently well posted, in the New York Sun, in 1909, summed up the arguments for and against the canal theory and the water-determination theories of Mars, and came to these conclusions:
"If the water vapor in the Martian atmosphere is sufficient in amount to yield an ice cap at the polar bright spots, the tension over the rest of the planet
must be such that canals will not be needed because of a sufficient precipitation; if the water vapor content is so slight that the polar caps are nothing but frost, no amount of engineering skill could cope with the tension which would evaporate whatever water may have started in the canals. Under terrestrial conditions these two extremes are well represented by the Hudson which never runs dry, and those rivers of the arid VVest which are greatest at the source and dwindle on their course until they end in a damp spot with bone-dry edges."
By the tension, of course, is meant the proportion of water vapor in the atmosphere which determines, in relation to the temperature, the amount of evaporation that will go on.
This same writer goes on to tell how the spectroscope was invoked to solve the problem:
"Fortunately we are not without appliances which may deal with this fundamental problem. The spectroscope yields a record of every sort of light which it dissolves, and the bands corresponding to water vapor have all been plotted on the spectrum. If these hands show at all, it is irrefragable evidence of the presence of water vapor, and in like manner the pronouncement of their definition gives a measure of the amount of such water vapor. If then, comparative observations are made simultaneously of an
illuminated object whose water vapor content is well established and of Mars, in which it is yet to establish that factor, the comparison of the bands in the two spectra will give a measure of the results in Mars.
"At the very favorable opposition in September (1909), the whole resource of the Lick Observatory staff was devoted to making this comparison.
"In order to avoid as much as possible of the water vapor content of the earth's atmosphere, greatest in its lowest levels, the observing station was equipped on the summit of Mount Whitney in the Sierras at an elevation of 14,501 feet and in a horizon markedly arid
"For purposes of the astronomical comparison the moon was taken as the standard. A long series of eclipse observations has shown that whatever atmosphere may persist about our satellite is optically indiscernible. Similar series of spectroscopic observations have shown that the water vapor at the moon is wholly inappreciable by the most delicate tests. If the spectrum of Martian light photo-graphed under the same terrestrial conditions shows no more water vapor bands than appear in the photographed spectrum of lunar light the conclusion is warrantable that water vapor on Mars is of such extreme tenuity as not to be made available for cultural purposes.
"The complete results of the Mount Whitney
observations have not yet been worked out, but Director Campbell authorizes the preliminary report that the comparison of a simultaneous Martian and lunar spectra proves that Mars has no more water about it than has the moon. He is concerned in the determination of this one fact in physics. The rest follows in its train of inexorable logic. If Mars has no more water than the moon the polar bright areas cannot be ice, snow, or hoar-frost; the most reasonable suggestion is that they are solidified carbon dioxide, the heaviest constituent of an atmosphere and the longest to linger over a dead world, itself a mantle of death and the shroud of animal life."
Now we are very grateful to this writer for his account of actual observations--in which we heartily concur--but in spite of the eloquence of his closing thoughts--no longer observations, the reader will notice, but mere speculation--we cannot follow him. We fear that his eloquent periods are here wasted, for if the reader remembers what we said a few pages back it is quite impossible that carbon dioxide is the constituent of the poles. For that constituent twinkles, glints, and again is clouded over--it can be nothing else than an aperture giving out light from a central sun and ever and anon clouded over. For whether there is water vapor on the exterior of Mars or not, there is certainly water
vapor on the inside. It is this water vapor that causes the interior clouds that have been observed to cut off the light of the interior sun. It is this sun itself that sends those periodical messages--glints of direct light that could never come from an inert mass of frozen carbon-dioxide or from a thin film of hoar-frost that is said to evaporate.
And let the reader note how this fundamentally false idea of the structure of the planet is misleading the orthodox astronomers all the time. Starting from a wrong basis they naturally attain to wrong results, and so instead of all their theories and observations fitting into one another and leading them nearer and nearer to agreement until they come together in the recognition of the truth, they cannot agree on a single thing. First, they tell us the temperature of Mars is relatively high, then it is so low that carbon dioxide freezes at the poles--in spite of the fact that at certain seasons of the year the poles of Mars are the warmest part of the planet--and then we are told that there is vegetation on the planet and again that there could not be because there is no water and so on in a continual disagreement which widens with the lapse of time and the procession of the arguments instead of decreasing as it would if the astronomers were on the right track.
But if the growing and declining of the alleged
polar ice-caps be interpreted as due to a melting and freezing of either water or carbon dioxide, how do those who hold to the idea explain the polar caps of Venus and Mercury?
Let us take Venus first. It is our nearest neighbor on the side nearer the sun, just as Mars is on the side farther from the sun. It is slightly less than the earth in size and has almost the same length of day.
F. W. Henkel, an English astronomer, writing in The English Mechanic and World of Science, remarks that:
"When Venus is near the sun, distinct evidence of the existence of an extensive atmosphere, twice as dense as our own, is obtained, and the spectroscope shows the presence of water vapor in some abundance. The dark portion of the planet's disc (that turned away from the sun) is occasionally seen faintly illuminated, (says Professor Young), recalling the aurora and other electrical manifestations on earth."
We shall have a good deal more to say about the aurora later on but for the moment we must let that point pass.
To continue Mr. Henkel's summary:
"The distance of Venus from the sun is only about three-quarters that of the earth, or about 67,000,000 miles, so that any area of its surface must receive about twice the amount of light and heat that an
equal area on the earth receives; but as we have already said, the presence of a more extensive atmosphere may to 'a considerable extent mitigate this, to our ideas, excessive amount."
And yet the author of this article immediately goes on to quote Professor Young to the effect that "air, water, lands, continents, mountains, polar snows, etc., all seem to be present."
Polar snows in a sun-drenched planet? That seems curious, and we begin to inquire what other astronomers have to say in the matter.
Not only does H. W. Warren, in his "Recreations in Astronomy," speak of the fact that the tropic zones of Venus extend nearly to the poles--on account of the great inclination of the axis of the planet's rotation--but a later authority, E. Walter Maunder, in his very authoritative book, "Are the Planets Inhabited?", has this to say--after describing the temperatures on the planet--about the climate of Venus:
"Here then is the sufficient explanation why the topography of Venus is concealed. The atmosphere will always be abundantly charged with water-vapor, and an almost unbroken screen of clouds will be spread throughout its upper regions. Such a screen will greatly protect the planet from the full scorching of the sun, and tend to equalize the temperature of day and night, of summer and winter, of equator and poles. The temperature range will be slight, and there will be no wide expanses of polar ice."
When we think of that, especially in consideration with the statement that the polar markings of Venus have never been seen to contract and expand at different times, it is obvious that these marks at the poles, in the case of Venus, are nothing less than the apertures through which light streams from a central sun.
But the astronomers, lacking this explanation, are hard put to it to account for what they see. On general principles one would imagine that similar phenomena should always be explained by similar causes. If, for instance, you once see an eclipse of the moon, and its cause is explained to you, you will at once recognize the next time you see an eclipse, that the same cause is at work. You would laugh at anyone who said that one eclipse was caused by the shadow of the earth being thrown on the moon, another eclipse by the flight of a huge body between the earth and the moon, and so on.
Yet the astronomers observing apertures at the poles of Mars explain them in one way when they observe similar apertures at the poles of Venus--they ought to explain those in the same manner. But they cannot do it, for they have postulated frozen water or frozen carbon dioxide as the cause of the polar caps of Mars, and they know there is nothing like that on Venus. So what do they say? Let
[paragraph continues] Hector MacPherson answer in his book on "The Romance of Modern Astronomy":
"Polar caps", he says, in his chapter on Venus, "have been observed, supposed by some to be some-what similar to those on our own planet and on Mars. Some astronomers, however, do not regard them as snow; the drawings of Schiaparelli represent them as separated by a dark shadow, which suggests that they represent two mighty mountain systems."
Before going on to a very remarkable observation, we may be permitted to criticize this idea in more than one way. In the first place, as we have said, it is absurd to explain one thing--a polar cap or area--by invoking snow in one planet or an open polar sea, and in another planet mountains. Why should mountains on Venus imitate a polar ice cap on Mars, or an ice cap on Mars look like and be placed just like a mountain range on Venus? It is scientific lunacy to argue in any such fashion. And we may be permitted to say also that Mr. MacPherson's language is too vague here. Is he trying to say that each so-called "mountain range" is separated from the surrounding surface of the planet by a shadow, or does he mean that one dark mountain range is separated from the other by a darker shadow--which in that case would lie all over the planet? We hope that nothing said in this book is said in such a manner
as will leave the reader in doubt as to which of two possible things we may mean.
But to follow Mr. MacPherson a little further. He quotes a French astronomer, Trouvelet, who in 1878, found the polar spots distinctly visible:
"Their surface," he wrote, "is irregular, and seems like a confused mass of luminous points, separated by comparatively sombre intervening spaces. This surface is undoubtedly very broken, and resembles that of a mountainous district studded with numerous peaks, or our polar regions with numerous ice-needles brilliantly reflecting the sunshine."
Our readers will at once recognize those luminous points for what they are gleams from the central sun. Trouvelet, not knowing this, involves himself in a mass of error in trying to explain what he saw. It is obvious that he observed the polar aperture during very cloudy weather and the gleams from the central sun were just struggling through the clouds at various points--he saw those and what he took to be sombre mountain masses were really the cloud banks through which the beams were breaking and which, of course, looked very sombre by contrast. It could not have been anything else, for, as we have just seen, the cloudy atmosphere of Venus, which is dense and never lifted, would never permit any light from the sun or other outer source to reach the surface and be reflected as this French astronomer assumes it was. And even if the light could reach the
polar cap of Venus it is admitted that that polar cap is not made of ice and so there would be no such ice-like reflection as the astronomer describes.
Here again we have a case in which the observed facts are explained by our theory, in which no other theory can be made to explain them, and in which, lacking our theory, the astronomers confusedly contradict each other when they try to reduce what they see to any rational explanation.
And just to show the reader how universally our theory works, let us refer to another planet on which observations can be made of the polar openings. It is Mercury--the planet which is so near the sun that it circles around it in eighty-eight days. Of this planet Richard A. Proctor, one of the best known astronomers of the nineteenth century, says:
"It may be mentioned in passing that one phenomenon of Mercury, if real, might fairly be regarded as indicating Vulcanian energies compared with which those of our own earth . . . . would be as the puny forces of a child compared with the energies of a giant. It has been supposed that a certain bright spot seen in the black disc of Mercury when the planet is in transit, indicates some sort of illumination either of the surface of the planet or in its atmosphere. In its atmosphere it can scarcely be; nor could any auroral streamers on Mercury be supposed
to possess the necessary intensity of lustre. If the surface of Mercury were glowing with the light thus supposed to have been seen, then it can readily be shown that over hundreds of thousands of square miles, that surface must glow with an intensity of lustre compared with which the brightness of the lime-light would be as darkness. In fact, the lime-light is absolute blackness compared with the intrinsic lustre of the sun's surface; and the bright spot supposed to belong to Mercury has been seen when the strongest darkening-glasses (or other arrangements for reducing the sun's light) have been employed. But there can be no manner of doubt that the bright spot is an optical phenomenon only."
Again we agree with the observation but not with the inference. Here is a spot of light, plainly seen through a telescope, so bright that the observer compares it to the incandescence of a sun. It is a much brighter light than any mere reflection could possibly give. But we must remember that to Proctor such an appearance must have been staggering in the extreme. He was not only not expecting it but he was utterly unprepared to see such a phenomenon. And so he is utterly unable to explain it. And it is a safe rule that when you cannot explain a thing you can make what looks like an explanation by giving the thing another name. So Proctor calls this
light "an optical phenomenon only." Well of course, it is an optical phenomenon, but why does he say "only?" Everything we see is an optical phenomenon, but we usually try to explain the optical phenomena. A man who saw optical phenomena that were without explanation or cause would be in a very dubious position. People would say he was "seeing things"--and their meaning would not be complimentary. But we cannot assume that Proctor's eyes had played him a trick. He was a trained astronomical observer. So what he saw must have had some explanation or cause behind it. He cannot have seen a "myth" as he himself asserts.
Now it is obvious to us that what he saw was the central sun of Mercury beaming directly through the polar aperture, and as Mercury is a small planet the interior sun would be rather near the aperture, certainly there would not be an aqueous atmosphere with clouds to darken its beams, and so that sun would shine with exceeding brightness. And it is notable that their beams did put Proctor in mind of the beams from the sun that shines in our heavens upon all the planets.
What more could be wanted than this to show that Mercury as well as the other planets has a central sun, that such a sun is to be met with universally?
Is it not significant that beginning with observations on Mars we are able to go on to Venus and
[paragraph continues] Mercury, apply the same tests, and get the same results? The tests, direct observation or photographic observation. The results, the invariable appearance of a central sun.