Seen through a telescope, Mars is not so red as it appears to the naked
eye. One of the best observers of it has compared it to an opal, and it
surely has some of the qualities of an opal in the diversity of aspect
that it shows to different observers from different points of view. No
other planet has been so subjected to controversy over what appears
on its surface. This is partly due to its being the only planet whose
surface is without doubt open to our view and in a situation where it
can be minutely studied, and partly to the fact that the controversy
involves questions concerning life and intelligence, which are always
of intense human interest. Matters of this vital sort are never
accepted without dispute. That is one way of getting at the truth.
In the intensity of the discussion the question of the existence of
the phenomena and that of the meaning ascribed to them are sometimes
unnecessarily made to depend upon each other. In the case of Mars it
may well be that there is less difference of opinion as to what is
really seen on its surface than as to the meaning of the phenomena.
There are recorded observations made of Mars as early as 272 B.C., more
than two thousand years ago, and it has been nearly two hundred and
fifty years since the snow-caps were first seen. Through the telescope
not only the snow-caps are plainly visible at the proper seasons, but
there are also visible dark patches over the surface, showing a variety
of color, and in certain parts changing somewhat as the seasons change.
It is one of these patches, the outline of which suggests a somewhat
twisted eye, that is known as the “eye of Mars.” The main surface of
the planet is reddish yellow in color; the patches on it are variously
described as gray, grayish green, or blue, colors which in combination
could easily take on a tone of any of them according to the eye of the
observer, and this portion of the planet’s surface does, in fact, show
first one and then the other of them predominating.
When the planet’s differences of color were first observed, the
reddish-yellow portion was supposed to be land, and the areas of
varying bluish-green and gray were thought to be the waters of the
ever-changing seas. A little after the middle of the last century
some keen eyes saw a few streaks or markings of some sort across the
land areas, and in 1877 a close study of the planet by an eminent
Italian astronomer, Schiaparelli, brought to his view many greenish
streaks, all directed toward the so-called seas, and sometimes seeming
to intersect there. In publishing this discovery Schiaparelli called
these streaks _canalli_, which is properly translated “channels,”
but appeared in English as “canals.” Since “canal” with us means
artificially constructed waterways, the discovery became at once one
of universal interest; for artificial waterways mean human beings to
construct them, and it was an intensely interesting thing to know
that Mars was probably inhabited with beings at least somewhat after
our own kind. It was a new world. The little planet became a topic of
absorbing interest to all of us. And thus began the controversy over
the habitability of Mars, and the meaning of its surface features, in
which astronomers, seeking only for the truth, have taken a much more
dignified part than they have sometimes been more or less sensationally
represented as doing. The discoverer of the so-called canals himself
believed them to be natural waterways cutting through the land after
the manner of our straits and channels, and had very little to say in
explanation of them. But his work gave a new impetus to the study of
this little brother world of ours.
In our own country the observatory at Flagstaff is the one the best
known among those doing research work on Mars; but it is not the only
one. The observatory there is finely situated in the thin, clear
atmosphere of Arizona, the mechanical facilities for such work are
good, and there seems no doubt that there are there some observers
who have eyes that were made for seeing. All that the sharp vision of
Schiaparelli saw has been seen there, and much more. Several hundred
canals have been discovered, and at certain seasons many of them have
appeared to become double. Their courses have been followed, and their
appearances and disappearances have been watched. Somewhere near six
hundred of them have been mapped. According to these maps, the canals
seem to be laid out with a geometrical precision such as nature is
not likely to follow; they run across some regions that were formerly
supposed to be water, and they have points of convergence every here
and there, forming at such points large dark areas.
Naturally, when a person has discovered any new and curious phenomenon
in nature he seeks to determine the exact meaning of it. It would have
very little interest for him if he did not, and it would be a dry lot
of facts that did not arouse a desire to do this. The interpretation
put upon what has been seen at the observatory at Flagstaff is, in
brief, about as follows:
The surface of Mars has no oceans or mountains. The reddish areas,
which form the larger part of the surface, are deserts. The blue-green
streaks are ribbons of vegetation along each side of artificially
constructed waterways, which are of immense length and cross and
recross each other until they somewhat resemble a network of lines
over the desert surface of the planet, and are used for irrigating
this arid region. The points where the canals converge and form the
large dark spots are oases made by the water carried by the canals.
The water is supplied by the melting of the caps of snow at the poles
during the Martian summer, the expanding of the lines of vegetation
seeming to occur at periods corresponding to the time required for the
water of the melting snow to reach the oases. The presence of this vast
system of artificial waterways covering a large part of the surface of
Mars makes it seem probable that “Mars is inhabited by beings of some
sort or other,” that these beings are not men such as we know anything
about, but that “there may be a local intelligence equal to or superior
to ours.”
These conclusions concerning what is seen on Mars are not held by
any one to be completely proved, but are thought by their author
to follow reasonably from the phenomena as observed. By persons
of a different temperament they are regarded as too complete an
explanation, particularly as the data upon which they are founded are
not undisputed. Some of the best astronomers have not been able even
to see the multitude of fine lines, much less to give any explanation
of them. Others do not regard it as certain that they are so geometric
in their outlines as to suggest anything more than cracks or clefts
in the surface of Mars, such as might be made by nature, and consider
that, instead of indicating life, human or other, they may be the marks
of age, such as similar lines or cracks which have been observed on
Mercury seem to be.
Also, it is not at all certain that there is sufficient water vapor in
the slight atmosphere of Mars to furnish the snow necessary for this
great irrigating system, nor the heat to melt it at the proper season.
The natural temperature of Mars would be, as we have seen, very low,
and unless it is modified in some way not yet indicated everything
points to a frigidity too intense to permit the continuance of life and
growth of any sort known to us.
These things must all be reckoned with before anything certain can be
known of the surface of Mars. The difficulty of pronouncing upon the
minute details is impressively indicated by Professor Moulton, who says
that, even under the finest conditions and with the best telescopes, it
is like viewing “a perfectly accurate relief map of the whole United
States made on such a scale that it would be only three inches in
diameter and held at a distance of three feet from the eye.” Under such
a near limit of vision, we can well see that differences of opinion
might arise.
The mere fact that some astronomers have not seen the lines on Mars
does not mean that they deny their existence. Some eyes have greater
defining power than others, as well as some telescopes, as every one
knows. But while all the lines and patches of color that are claimed
to have been seen on Mars doubtless have been seen by some persons,
yet it is not necessary to accept the interpretation of them given
by lively-minded observers when it is not convincing. There may be
vegetation on Mars, and even intelligent beings. We do not know; and
thus far there is not much to support, even by inference, the view
that there are. If we want the truth, we are brought no nearer to it
by giving full credence to a speculative theory simply because it is
interesting and pleasant; and thus far all theories advanced as to the
nature of the surface markings on Mars are speculations, though there
is no doubt that the marks are there. It is pleasing, however, to
contemplate the idea of there being on Mars, or on any other planet, an
active intelligence of any sort resembling what we have here on earth,
and it is not strange that such a wide-spread popular interest should
attach to Mars, in view of what has been suggested by the markings on
its surface.