MARS AND ITS MYSTERY
[Illustration: LOWELL'S GLOBE OF MARS, 1903. _Frontispiece_]
MARS
AND ITS MYSTERY
BY
EDWARD S. MORSE
MEMBER NATIONAL ACADEMY OF SCIENCES
Author of "Japanese Homes and their Surroundings,"
"Glimpses of China and Chinese Homes," etc.
_ILLUSTRATED_
BOSTON
LITTLE, BROWN, AND COMPANY
1906
COPYRIGHT, 1906,
BY LITTLE, BROWN, AND COMPANY.
_All rights reserved_
Published October, 1906
THE UNIVERSITY PRESS, CAMBRIDGE, U. S. A.
To
PERCIVAL LOWELL
WHO HAS BY HIS ENERGY AND SCIENTIFIC SPIRIT
ESTABLISHED A NEW STANDARD FOR
THE STUDY OF MARS
THIS BOOK
IS AFFECTIONATELY INSCRIBED
PREFACE
The following pages have been written for the general reader. The
controversies over the interpretation of the curious markings of Mars
and the wide divergence of opinion as to their nature first turned my
attention to the matter. The question of intelligence in other worlds
is of perennial interest to everyone, and that question may possibly
be settled by an unprejudiced study of our neighboring planet Mars.
Knowing the many analogies between Mars and the Earth, we are justified
in asking what conditions really exist in Mars. Instead of flouting at
every attempt to interpret the various and complicated markings of its
surface, we should soberly consider any rational explanation of these
enigmas from the postulate that the two spheres, so near together in
space, cannot be so far apart physically, and from the fact that as
intelligence is broadly modifying the appearance of the surface of the
Earth, a similar intelligence may also be marking the face of Mars.
A student familiar with a general knowledge of the heavens, a
fair acquaintance with the surface features of the Earth, with an
appreciation of the doctrine of probabilities, and capable of
estimating the value of evidence, is quite as well equipped to examine
and discuss the nature of the markings of Mars as the astronomer.
If, furthermore, he is gifted with imagination and is free from all
prejudice in the matter, he may have a slight advantage. Astronomers
are probably the most exact of all students as to their facts, and in
this discussion there is no attempt to introduce evidence they do not
supply, as the frequent quotations from their writings will show.
Having studied Mars through nearly one presentation of the planet with
the great refractor at the Lowell Observatory, what I saw with my own
eyes, uninfluenced by what others saw, will be presented in a short
chapter at the end of this book.
I wish to express my obligations to Professor Percival Lowell for the
privileges of his observatory, for many of the illustrations in this
book, and for his unbounded hospitality during my visit to Flagstaff.
I am also deeply indebted to Mr. Russell Robb for valuable assistance
during the preparation of the manuscript.
E. S. M.
SALEM, MASSACHUSETTS,
October, 1906.
CONTENTS
Page
I. INTRODUCTION 1
II. IMMEASURABLE DISTANCES OF SPACE 7
III. OTHER WORLDS INHABITED 14
IV. LOWELL'S BOOK ON MARS 31
V. TESTIMONY OF ASTRONOMERS 51
VI. THE STUDY OF PLANETARY MARKINGS 70
VII. DIFFICULTIES OF SEEING 79
VIII. VARIATION IN DRAWING 94
IX. THEORIES REGARDING THE CANALS 100
X. COMMENTS AND CRITICISM 125
XI. ATMOSPHERE AND MOISTURE 134
XII. NOTES ON IRRIGATION 141
XIII. VARIETY OF CONDITIONS UNDER WHICH LIFE EXISTS 147
XIV. MY OWN WORK 158
XV. WHAT THE MARTIANS MIGHT SAY OF US 166
XVI. SCHIAPARELLI, LOWELL, PERROTIN, THOLLON 172
XVII. LAST WORDS 180
INDEX 189
LIST OF ILLUSTRATIONS
LOWELL'S GLOBE OF MARS _Frontispiece_
Fig. 1. PLANISPHERE OF EARTH _Page_ 61
PLATES
I. TOBACCO CULTIVATION UNDER CLOTH, PORTO RICO _Page_ 50
II. DRAWINGS OF SOLAR CORONA " 96
III. CHINESE BOWL, SHOWING CRACKLE " 107
IV. MUD CRACKS ON SHORE OF ROGER'S LAKE, ARIZONA " 108
V. NATURAL LINES, CRACKS, FISSURES, ETC. " 112
VI. ARTIFICIAL LINES, RAILWAYS, STREETS, CANALS, ETC. " 113
VII. DOME OF LOWELL OBSERVATORY, FLAGSTAFF, ARIZONA " 158
VIII. TWENTY-FOUR INCH TELESCOPE, LOWELL OBSERVATORY " 160
IX. DRAWINGS OF CANALS OF MARS BY THE AUTHOR " 162
PORTRAITS
GIOVANNI VIRGINIO SCHIAPARELLI _Page_ 172
PERCIVAL LOWELL " 174
HENRI PERROTIN " 176
M. THOLLON " 178
_Life not wholly unlike that on the earth may therefore exist
upon Mars for anything we know to the contrary._
SIMON NEWCOMB.
MARS AND ITS MYSTERY
I
INTRODUCTION
Had some one asked, fifty years ago, Is the Sun composed of chemical
elements with which we are familiar? Shall we ever know? the question
would not have been deemed worthy of a second thought. Realizing
what has been accomplished, not only regarding the constitution of
the Sun, but of the most remote stars, we are encouraged to ask: Is
Mars inhabited? Shall we ever know? To what groups of students are
we to appeal for an answer? If we want to know the diameter of Mars,
its weight, the form of its orbit, the inclination of its axis, the
period of its revolution around the Sun, and its rotation period,
its ephemeris and its albedo, we ask the astronomer, for he has the
instruments with which to observe and measure, and the mathematical
knowledge necessary to reduce the measurements. If Mars were
incandescent, we should appeal to the astrophysicist for information
regarding its chemical composition. If, however, we want to know the
probability of Mars being the abode of life, we should appeal to one
who is familiar with the conditions of life upon our own globe. If the
question is asked as to the existence of intelligence on the planet,
we endeavor to trace evidences of its surface markings, and their
character, whether natural or artificial. Knowing how profoundly man
has changed the appearance of the surface features of our own globe in
the removal of vast forests, in the irrigation of enormous tracts of
sterile plain, the filling up of certain areas, like Peking, Tokio,
London, with material having a different reflecting surface, we are to
scan the surface of Mars for similar modifications, and for an answer
ask those who are familiar with physical geography, with meteorology,
with geology, including the character of natural cracks or crannies,
deep cañon, or range of mountains, or any of the great cataclysms which
have scarred the face of the Earth. Taking the great mass of facts
as they are presented to us by astronomers, to what class are we to
appeal as to the probability of life in other worlds? What class will
form the most rational conclusions? Will it be the circle-squarers,
perpetual-motion cranks, spiritualists, survivals of a past who believe
the world is flat, those who have "anthropomorphic conceptions of
the Supreme" and Hebraic conceptions of the origin of things, or will
it be those who value observation and experiment, who appreciate the
importance of large numbers, and who are endowed with a tithe of
imagination? Most certainly the latter class.
In approaching the interpretation of the markings of Mars we should
first glance at a brief historical summary of what has already been
done. We should examine the testimony of those who have seen and
drawn the canals; we are then better prepared to examine the records
of the latest observations and the explanation of their nature. In
the meantime an inquiry must be made as to whether the mathematical
astronomer, after all, is best fitted to judge of the surface features
of a planet. Next we should take up in the following order the
evidences, which are overwhelming, that a network of lines, geodetic
in their character, mark the surface of Mars. It has been claimed
that these lines show the result of irrigation, and, therefore, the
irrigation features of our own planet should be examined. It has been
objected that many astronomers have not been able to see the markings,
and consequently their existence has been doubted. It will then be
proper to point out that the difficulties of seeing are very great,
and that the acutest eyesight, coupled with long practice, is necessary
to recognize the markings. It has been objected that the drawings of
the minuter details of Mars vary with different observers. It will
be necessary to show that every kind of research employing graphic
representation labors under the same difficulty, and none more so than
astronomy. It has been objected that there is not sufficient moisture
and atmosphere in Mars to sustain life, and this must be answered by
those only who are familiar with conditions affecting life on our own
planet.
Various theories have been advanced, some of them physical, to
explain the markings of Mars, and these must be considered, and, if
possible, answered. Comments and criticism are difficult to repress,
as the discoveries of Schiaparelli and the additional discoveries and
deductions of Lowell have evoked discussions, which, in some instances,
have been harsh and unreasonable, and, in one case, positively
ridiculous. Schiaparelli has been called an impostor, and Lowell has
come in for his full share of vituperation and innuendo. If this
portion of the discussion is considered unparliamentary, the attitude
and language of certain astronomers have provoked it.
A brief account is presented of what the author was enabled to draw of
the Martian details, with a transcript of his notes made at the time
of observation, and finally a little imaginary sketch is given as to
how the world would look from Mars; and if similar kinds of astronomers
existed there, what comments and objections they might offer as to the
inhabitability of the Earth.
Such flights of the imagination are justified in that it gives one
a chance to appreciate the weakness of some of the arguments urged
against the idea of intelligence in Mars.
It will be objected that some of the names herein quoted are not
recognized as astronomers. I can only say that in every instance
I have found references to the writings and essays of those that
might be objected to in the pages of the "Observatory," and other
reputable astronomical journals, and in no instances accompanied by
adverse comment or criticism. If astronomers--even the distinguished
Schiaparelli--quote these names in scientific memoirs, I may venture to
do the same in a book written for the general reader. The objection,
however, has always presented itself with every controversy; it was
conspicuously marked in the passionate discussions over Darwin's
"Origin of Species." The intelligent laity recognized the truth of
Darwin's proposition long before the zoölogist began to waver. Essays
by the unprofessional supporting Darwin's contention were discredited
because the writers were not trained naturalists. The history of
invention is crowded with instances where devices and processes have
been invented by men whose trades or professions were the least likely
to enable them to originate such ideas.
II
IMMEASURABLE DISTANCES OF SPACE
_It is therefore perfectly reasonable to suppose that
beings not only animated but endowed with reason inhabit
countless worlds in space._
SIMON NEWCOMB.
Until within recent centuries, man has not only believed that he and
his kind were the only intelligent creatures in the universe, but
that the little round ball on which he lived was the dominant part
thereof. So rooted for ages was this conviction that it became fixed
in man's mental structure, and hence the survival of the idea that
still lingers in the minds of a few to-day. The conclusion was natural,
however, for the behavior of the starry heavens and the Sun and the
Moon seemed sufficient evidence that man, and the surface upon which
he lived, was the centre of the universe. The stars were bright points
of light, the Moon a silver disk, and the Sun a heat and light giving
ball of fire, equally diminutive and not far away. Let one realize for
a moment the experience of these early people. Everything aerial,
with the exception of feathery birds, fluffy bats and flying insects,
was composed of the lightest particles--cottony seeds, reluctantly
falling snow-flakes, motes in the air, smoke and vaporous cloud, and,
in contrast, the rock-foundationed and irregular surface upon which
the people dwelt, and flat as far as man had reached. What wonder,
then, that man viewed these brilliant points and dazzling disks as
objects of no great size and not far away, hauled across the heavens
by unseen spirits of some kind. The marvel of it all is, not that
they believed as they did, but that any other views of cosmography
could have been established. And yet the successive increments of
astronomical knowledge, founded apparently on the soundest mathematics,
were adopted in their turn. What more convincing than the epicyclic
theory of Ptolemy, buttressed by figures so ingenious and convincing,
that the theory might have lasted till now except for the truer
understanding of planetary movements in relation to that of the Earth?
All through this history are found traces of the barriers erected by
prejudiced conservatives, of which the attitude of Tycho Brahe is a
good example, though in this case it was probably his belief in the
Hebraic conception of the universe which excited his opposition to
Kepler's views, a conception which, unfortunately for the progress of
astronomical research, still lingers among certain observers to-day and
places them in precisely the same category with Tycho Brahe.
With the gradual accumulation of knowledge it was found that of all
the innumerable illuminated bodies in the heavens, only one,--just
one,--the Moon, revolved around the Earth, and that the Earth instead
of being all dominant in the affairs of the universe, played a very
minor part, and, instead of being master, was a very humble midget
revolving around the Sun; that, indeed, with the exception of the
Moon, there were visible to the naked eye only three bright points
of light in the whole range of the heavens more insignificant in
size,--Mercury, Venus, and Mars,--while the other planets were vastly
larger, and had many more satellites revolving around them. Then it
was found that, with the exception of the few planets, the myriad
stars had no connection with the Sun whatsoever, that the Sun was
no longer the centre of a great universe. Later it was discovered
through spectroscopic analysis that all the myriad of stars were
composed of chemical elements similar to our Sun. Here, then, was the
startling revelation that our Sun was simply a star, and that the stars
represented a "universe of Suns," and, if we could get near any one
star of the millions that sparkle in the heavens telescopically, we
should see it as a round ball emitting light and heat. It was perhaps
humiliating to find that our Sun was so insignificant in size that
from Sirius, for example, it could not be seen with the naked eye, so
small indeed that in the close companionship of other stars it would be
swallowed up by their greater size and brilliancy.
To assume, then, that our Sun, so identical to the stars in heat and
light emitting properties, was the only Sun that had revolving around
it a few minute balls, would be as absurd as if one should go on a
pebbly beach, extending from Labrador to Florida for example, and
picking up a single pebble, should have the hardihood to assert that
this pebble was the only one, among the millions of pebbles, upon which
would be found the bits of seaweed and little snails which it might
support. The overwhelming vastness of the universe is entirely beyond
the grasp of the human mind. The mere statement that it requires so
many years for the light to reach us from a certain star, the parallax
of which has been rudely established, affords one only a faint glimmer
of the truth. The swing of our Earth about the Sun gives us a base line
of 186,000,000 of miles, and yet, with this enormous base from which
to subtend an angle, only a very few of the myriad of stars show the
slightest displacement; the others exhibit no more signs of divergence
than if while looking at them we had simply moved our heads from one
side to the other! Fixed stars they appear to be, and are so called,
though we are told they are all drifting in various directions, as our
star-Sun is.
Only by reducing all these vast distances and dimensions to a minute
scale can the mind realize the futility of ever comprehending the
illimitable distances of space.
In order to consider the attitude of the Earth in relation to the
Sun and the nearest fixed star, we will reduce the Sun's diameter of
866,000 miles to the dimensions of a ball one inch in diameter; the
Earth reduced to the same scale would be a minute speck less than one
one-hundredth of an inch in diameter; a perforation in paper made by
the finest cambric needle would represent the size of this minute
speck, the Earth. Following this scale we should place this speck nine
feet from the inch ball, this distance representing 93,000,000 of
miles, the Earth's distance from the Sun; Mars would be a still smaller
speck a step farther off. Let us now proceed to Boston Common, for
example, and on the smooth playground place our inch ball representing
the Sun; taking three good steps we should place our minute speck,
representing the Earth, upon the ground where it would be immediately
lost in the fine gravel; another step and we would place a still
smaller particle, representing Mars. How big a circle on the Earth's
surface, using the inch ball as a centre, should we have to describe in
order to include the nearest fixed star? Such a circle would reach to
Detroit, Michigan, and Columbus, Ohio, or Wilmington, North Carolina!
To find a circle which would include eight other fixed stars next in
distance, and only eight of the thousands which render the heavens
so beautiful on a clear winter's night--we should run such a circle
through the centre of Hudson Bay, the waters of southern Greenland,
Lake Winnipeg, and New Orleans!
In this broad way only can we form a dim conception of the overwhelming
distances of space, and, in this absolutely unthinkable space, our
little Sun, with its constant rain of meteoric dust, an occasional
comet, and its microscopic planets are literally bunched together. To
admit, as we must then, that one of these motes has had irrigating
canals on various parts of its surface since prehistoric times, and the
other mote has nothing of the sort despite the geodetic lines that are
seen marking its surface, is simply preposterous. Their disposition,
their visibility coincident with the Martian summer, becoming apparent
only when the snow caps melt, their convergence towards centres of
distribution, all go to prove by the simplest analogy an identity of
structure. Certainly the overwhelming force of Lowell's observations
and arguments baffles any other reasonable explanation of the character
and purpose of these markings. Here are the lines, some following the
arcs of great circles, all appearing precisely when they should appear,
and in progressive strength from the north when the vivifying water
from the melting snow cap first starts the vegetation. Why certain
parallels or doublings are observed in some of the canals is about as
puzzling to us as the checkerboard townships of the West would appear
to a Martian, where some would be yellow with the ripening grain while
others, uncultivated, would appear of a different color.
III
OTHER WORLDS INHABITED
_Whether the other fixed stars have similar planetary
companions or not is to us a matter of pure conjecture,
which may or may not enter into our conception of the
universe. But probably every thoughtful person believes
with regard to those distant suns that there is in space
something besides our system on which they shine._
TYNDALL.
It would be a waste of time to attempt an interpretation of the
markings of Mars as a result of intelligent effort, if it could be
proved beyond a reasonable doubt that our globe was not only unique
among the bodies which probably accompany the innumerable suns, but was
the only body, among them all, sustaining creatures of intelligence. If
life exists in other planets of a nature with which we are familiar,
then the physical conditions must be similar to those of our own
planet. Later we shall point out the infinite variety of conditions
under which life--even man--exists on this globe, and it will be
shown that the question of higher or lower temperature, more or less
humidity, higher or lower atmospheric pressure, greater or less force
of gravity, can have but little weight in discussing the probability of
life in other worlds.
In a planet devoid of atmosphere, or a sphere glowing with its own
heat, we may decide without question that life does not exist. Even
in a globe in many respects like our own it would be hazardous to
conjecture the kinds of organic forms in which it is manifested.
Reasoning from analogy, if life exists in Mars, or other spheres in
infinite space, it must have originated under much the same conditions
as it originated here; at the outset the most primitive bits of
protoplasm. But has life appeared in Mars? Tyndall, in graphic words,
pictures the rounding of worlds from nebulous haze, and then says,
"For eons, the immensity of which overwhelms man's conception, the
Earth was unfit to maintain what we call life. It is now covered
with visible living things. They are not formed of matter different
from that around them. They are, on the contrary, bone of its bone
and flesh of its flesh." Mars must come in the same category. It is
a part of the original nidus from which our world was condensed, and
however life originated in the past, the conditions for its origin,
at least, must have been as favorable on the surface of Mars, as on
the surface of the Earth, and, so far as we know to the contrary, even
more favorable. In the beginning, Mars cooled and hardened with all
those behaviors of contraction, condensation of vapor on its surface,
erosion, etc., and it is impossible to avoid the conviction that life,
as on our Earth, arose under the same physical conditions. Recalling
the resemblance which Mars bears to the Earth, and the data which have
already been established, we behold a world in many respects like ours,
with its sunsets and sunrises, winds that sweep over its surface, the
dust storms from the deserts, its snow-storms and snow-drifts, its
dazzling fields of white in the north, with an occasional snow-storm
that whitens the planet far down in latitude; the seasonal changes,
and, most important of all, the melting ice caps, with rivulets and
torrents, temporary arctic seas and frozen pools, its great expanses
of vegetation and sterile plains. We have in Mars the variety of
conditions under which life has assumed its infinite variety of aspects
on the Earth, and which, by analogy, should have passed through similar
stages in Mars. Life at the outset must have been protoplasmic; then
came contractile tissue, muscular bundles, hardened structures within
and without for their support, nerves to animate the muscles, and
protection for nerve-trunk, either rigid or flexible. Hard parts might
vary under a different force of gravity, though there might appear
types of structure that could be classified with our own.
All such conditions, however, are mere surmises, for about such matters
we can reason only from analogy. The first proposition to establish is
that the conception of the plurality of worlds is not unreasonable, and
second, that many of the most eminent astronomers have believed in the
inhabitability of other worlds, and this justifies a reasonable man to
follow the inquiry. The belief is based upon legitimate analogies which
have thus far guided man in every generalization, in the establishment
of principles, and are continually appealed to in the details of every
day's experience.
From remote times it has been taken for granted by the best minds
that other worlds besides ours sustain life. The early belief in the
plurality of worlds was based on the idea that since spheres like ours
had been fashioned by the Almighty they must have been made for the
same purpose for which our globe seemed intended, to sustain life, and
Scripture was freely quoted in support of the idea.
Sir David Brewster, in his book "More Worlds Than One," says that the
doctrine of the plurality of worlds was maintained by almost all the
distinguished astronomers and writers who have flourished since the
true figure of the Earth was determined: "Giordano Bruno of Nola,
Kepler, and Tycho believed in it; and Cardinal Cusa and Bruno, before
the discovery of binary systems among the stars, believed also that
the stars were inhabited. Sir Isaac Newton likewise adopted it, and
Dr. Bentley, Master of Trinity College, in his eighth sermon on the
Confutation of Atheism from the origin and frame of the world, has ably
maintained the same doctrine. In our own day we may number among its
supporters the distinguished names of Laplace, Sir William and Sir John
Herschel, Dr. Chalmers, Isaac Taylor, and M. Arago."
The attitude of the intelligent world to-day is well shown in a recent
number of London "Nature," where in a review of a book by Wallace,
endeavoring to show that this world alone sustains life, the reviewer
ends by saying: "To consider this Earth as the only inhabited body in
the stellar universe, a reversion to prehistoric ideas, may or may not
be an advance, but it will require very strong arguments before we can
be brought to consider that its isolation in the Cosmos is indeed a
fact." Until the discovery by Schiaparelli of the network of lines in
Mars, laid out with seemingly intelligent precision, the arguments for
the inhabitability of other worlds were based entirely upon analogy.
Sir Richard Owen, the great comparative anatomist, in supporting the
contention that life existed in other planets, said: "The grounds of
belief vary with the probability of a proposition; if nothing better
than analogy can be had--on analogy will belief be based."
Professor O. M. Mitchell, the first director of the Cincinnati
Observatory, in his work on "Popular Astronomy," says, in regard to the
doctrine of the plurality of worlds: "It would be most incredible to
assert, as some have done, that our planet, so small and insignificant
in its proportions when compared with other planets with which it is
allied, is the only world in the whole universe filled with sentient,
rational and intelligent beings capable of comprehending the grand
mysteries of the physical universe."
The eminent French astronomer, M. Flammarion, has, in an eloquent
passage in his "Plurality of Worlds," portrayed the vastness of the
universe and the utter insignificance of our Earth in the immensity of
space: "If advancing with the velocity of light[1] we could traverse
from century to century this unlimited number of suns and spheres
without ever meeting any limit to this prodigious immensity where God
brings forth worlds and beings; looking behind, but no longer knowing
in what part of the infinite to find this grain of dust called the
Earth, we should stop fascinated and confounded by such a spectacle,
and uniting our voice to the concert of universal nature we should say
from the depths of our soul, Almighty God! how senseless we were to
believe that there was nothing beyond the Earth, and that our abode
alone possessed the privilege of reflecting thy greatness and honor."
Compare these elevating thoughts with the shrunken attitude of one who
has the conceit to imagine that he and his kind are not only alone
in the universe but superadds to this monstrous conception the idea
that the millions of great suns are designedly waltzing around solely
for his edification and amusement, unmindful of the heedless way in
which the millions of his race regard the overpowering majesty of the
heavens. To the thousand millions that live to-day, and the thousand,
thousand millions that have perished in the past, the starry heavens
have never excited an emotion grateful, reverent, or curious, unless
a flaming comet, or an eclipse of the Sun or Moon occurred, and then
with superstitious fear have they gone grovelling in the dust.
An astronomer imbued with Hebraic conceptions of the universe is
poorly equipped to appreciate the arguments in favor of life in other
worlds. He may be keen in perceiving lines in the spectrum, and the
significance of their lateral displacement, but possessed with a
belief--the result of early training--that a little two-legged human
molecule could command the Sun and Moon to stand still, a realization
of his own insignificance, or the possibility of intelligence in other
worlds, must forever remain beyond his grasp. Emerson said "the dogmas
shrivel as dry leaves at the door of the observatory." They never
shrivel for such minds, but grow and flourish with a density that
obscures by, its rankness every rational conception of the heavens
above. As an illustration of the attitude of such mentalities we have
to go back fifty years, for few survive to-day. Edward Hitchcock,
Professor of Geology and Theology at Amherst, wrote a book just fifty
years ago entitled "Plurality of Worlds," in which he denounces the
idea; but observe the precise way in which he lays down the law: "The
planets had no vital tendencies, they could have had such given only by
an additional act or series of acts of creative power. As mere inert
globes, they had no settled destiny to be the seats of life; they could
have had such a destiny only by the appointment of Him who creates
living things and puts them in the places which he chooses for them"
(page 352).
It may be objected that it is useless to bring up these old theological
conceptions, as the world has happily gone beyond them, and only in an
atavistic manner do we find a few still holding them; nevertheless it
may be safely asserted that fifty years hence we shall look back upon
the attitude of certain astronomers to-day with much the same pity and
amusement which excites us when we regard the attitude of a similar
class in the middle of the last century.
Tyndall expresses the universal belief of thinkers in whatever line
of work, that life is by no means confined to this Earth. He says:
"Whether the other fixed stars have similar planetary companions or
not is to us a matter of pure conjecture, which may or may not enter
into our conception of the universe. But probably every thoughtful man
believes, with regard to these distant Suns, that there is, in space,
something besides our system on which they shine."
One class of objectors to the idea that other worlds are inhabited
endeavors to show that our position in the universe is unique, that the
solar system itself is quite unlike anything existing elsewhere, and,
to cap the climax, that our own little world has just the right amount
of water, air, and gravitational force to enable it to be the abode of
intelligent life, and nowhere else in the broad expanse of heaven can
such physical habitudes be found as will enable life to originate or to
exist!
In a memoir on the "Evolution of the Solar System," by Professor T.
J. J. See, the author, while not denying the possibility of other
systems like our own, still considers our system unique. Here are his
words: "Therefore, while observation gives us no grounds for denying
the existence of other systems like our own, it does not enable us
to affirm, or even to render probable, that such systems do exist."
Because a number of binary stars have been discovered in which the two
stars are nearly equal in mass, and their orbits highly eccentric, he
therefore concludes that the millions of stars that stud the heavens
are probably without satellites. The unreasonableness of this attitude
is emphasized by realizing that these innumerable suns are similar
to our own Sun, as revealed by the spectroscope, and have a similar
eruptive energy. Professor Newcomb, however, says: "Evidence is
continually increasing that dark and opaque worlds like ours exist and
revolve around their primaries." Had Mr. See discovered that every
star of the many million was accompanied by another star nearly equal
in mass, with its marked eccentric behavior, then only would he be
justified in his inference that our solar system was indeed unique.
When one realizes that the stars are at such unimaginable distances
that the highest powers of the telescope reveal even the nearest of
them only as points of light--not as disks--and when one further
realizes that the satellites of our Sun, even the largest of them,
are diminutive globes compared to the vastness of the Sun, it seems
unreasonable if not impossible to entertain the idea that none of these
remote stars are accompanied by satellites, and that, therefore, this
little Sun of ours stands without parallel in the universe.
Tyndall, in his famous reply to the critics of his Belfast address,
in speaking of the origin of life, referred to the Nebular Theory
as follows: "According to it our sun and planets were once diffused
through space as an impalpable haze out of which by condensation
came the solar system. What caused it to condense? Loss of heat.
What rounded the sun and planets? That which rounds a tear,
molecular force." In these terse and graphic expressions we are made
to understand the universality of law. So far as we have sounded
the depths of the stellar universe we see the same obedience to
gravitational laws, the same flashing lines in the spectrum. We
encounter no phenomena that cannot be explained, or at least inferred,
by the knowledge we have obtained from our little mote of the Cosmos.
Mr. See thinks it remarkable that "previous investigators have almost
invariably approached the problem of cosmogony from the point of
view of the planets and satellites, and that no considerable attempt
has been made to inquire into the development of the great number of
systems observed among the fixed stars." It is true our planetary
system has been used as a standard of measurement for the universe,
and a very comprehensive standard it has proved to be. The law of
universal gravitation was based on terrestrial and lunar observations,
spectroscopic analysis was determined in a terrestrial laboratory. As
George Iles says, a coal of fire may be raked from a grate and broken
up to illustrate the rapid cooling of smaller masses. Even a child's
spinning top may be used in an astronomical lecture. The study of our
Sun led to the study of the fixed stars, and so our little system
has thus far furnished us with examples and illustrations by which we
interpret the universe.
In our solar system we have a fair sample of the Cosmos in miniature,
though our Sun is so modest in size, compared with the great orbs that
appeal to us by their number and brilliancy. So far as our telescopes
have sounded the heavens we find nebulous clouds in their structure
showing inchoate masses, orbital and spiral arrangements, condensations
in their centres. We have the binaries with their extraordinary
properties, we have variables with their dark bodies revolving around
their primaries. In our little system we also have dark bodies
revolving around a luminous primary, from one of which we endeavor
to interpret the mysteries of the universe; we have loose masses,
as in comets with enormously elongated orbits; we have spheres of
insignificant size, with small bodies revolving around them, and these
epitomes revolving around a central sun; we have one of these bodies
with meteoric rings; and, in the case of our own globe, a satellite of
such size that except in the form of its orbit it might well represent
a binary in embryo;--and, finally, a host of bodies big enough to
reflect the rays of the sun, pursuing their various orbital paths.
We are told that the stars are as distant from each other as we are
from them. We may regard these systems of nebulæ, variables, doubles,
etc., as different kinds or species of heavenly bodies; and to assert
that our system is the only individual of the species in the universe
seems contrary to all celestial analogy, for do we not have hundreds of
binaries, thousands of variables, millions of suns, revealing the same
fiery energy and consuming the same elemental fuel?
Professor Newcomb in his "Reminiscences" describes his first sweeping
the heavens, at random, with the then new twenty-six inch refractor
at the Naval Observatory and discovering a little cluster of stars so
small and faint that the individual stars eluded even the great power
of this instrument. He says: "I could not help the vain longing which
one must sometimes feel under such circumstances, to know what beings
might live on planets belonging to what, from an earthly point of view,
seemed to be on the border of creation itself." One would suppose that
this expression of a longing to ascertain the character of the beings
inhabiting planets circling these distant suns would induce one to
study a planet analogous to our Earth, and so near in comparison to
these unimaginable distances as to be within a hand's grasp, so to
speak. The little interest Professor Newcomb has taken in the subject
is well expressed in his late book "Astronomy for Everybody." In his
chapter on Mars, in which _Everybody_ is certainly interested, he says:
"The reader will excuse me for saying anything in this chapter about
the possible inhabitants of Mars. He knows just as much of the subject
as I do, and that is nothing at all." He might at least have given the
various pronouncements of Schiaparelli, Lowell, and others as to the
probable character of these remarkable markings on Mars, and their
supposed significance.
While Professor Newcomb's attitude on the question of the plurality
of worlds has been somewhat conservative in the past he has lately,
however, expressed himself on the question in no uncertain terms. In a
recent article in "Harper's Magazine," entitled "Probability of Life
in Other Worlds," he has lent his sanction to the rational idea that
other worlds may be the abode of intelligent creatures. His recognition
of the principle will do much to offset the influence if it ever had
any, of a recent book published in England by Alfred Russel Wallace,
in which the distinguished author attempts to show that this world
stands alone as the abode of intelligent life. Despite his epoch-making
work with Darwin, nearly fifty years ago, which must forever merit our
gratitude, and the charm of his various essays on protective coloring,
mimicry, theory of birds' nests, etc., he has since those lucid days
expressed convictions of such a nature that if a future DeMorgan
should write on human paradoxes he would classify Mr. Wallace as chief
among them. A profound believer in evolution, he exempts man from the
inexorable logic of the principle with about as much reason as if,
confessing his belief in the nebular hypothesis, he should insist that
the Earth was an exception.
But to return to Professor Newcomb's recent utterances. In the
above-mentioned article he says: "Not only does life, but intelligence,
flourish on this globe under great variety of conditions as regards
temperature and surroundings, and no sound reason can be shown
why, under certain conditions which are frequent in the universe,
intelligent beings should not acquire the highest development." Again
he says: "Life, not wholly unlike that on the Earth, may therefore
exist upon Mars, for anything we know to the contrary. More than this
we cannot say." In his final summing up Professor Newcomb says: "It is
therefore perfectly reasonable to suppose that beings not only animated
but endowed with reason inhabit countless worlds in space."
It would seem as if a mind capable of entertaining an idea of our
uniqueness in the universe betrays the survival of a mental condition
which, centuries ago, regarded the stars as bits of luminous material
expressly designed to illuminate this little earth, around which they
all pursued their daily paths.
IV
LOWELL'S BOOK ON MARS
_This whole arrangement presents an indescribable
simplicity and symmetry which cannot be the work of chance._
SCHIAPARELLI, in writing of the canals.
In a discussion of the surface markings of Mars a broad sketch of
what has already been accomplished in the study of that planet
should be given for the general reader. I know of no better way of
doing this than by giving a brief abstract of Percival Lowell's
epoch-making work entitled "Mars." In this book he presents in a clear
and striking manner the results of his own work covering continuous
observations of the planet for many years. The preface is dated from
Flagstaff, Arizona, 1895. Since that time he has issued three volumes
of Memoirs, in quarto, of the Lowell Observatory, and a number of
Bulletins in which he presents many additional facts confirming
previous observations, besides new observations; and finally, in a late
Bulletin, he has presented photographs of Mars made by his assistant,
Mr. Lampland, in which a number of canals plainly show, thus setting
forever at rest the question of the subjective character of the
markings. The student must, however, follow the advice of an English
reviewer and by all means read the book.
"To determine," says Mr. Lowell, "whether a planet be the abode of
life in the least resembling that with which we are acquainted, two
questions about it must be answered in turn: first, are its physical
conditions such as render it, in our general sense, habitable; and
secondly, are there any signs of its actual habitation? These problems
must be attacked in their order, for unless we can answer the first
satisfactorily, it were largely futile to seek for evidence of the
second." The reason why Mars in certain years becomes so conspicuous
is that its orbit is highly eccentric. Every two years--the period of
its revolution about the Sun--brings it nearest to the Sun, and once in
fifteen years we find ourselves between it and the Sun at its nearest
approach.
Huyghens, in 1659, made a drawing of the dark region on Mars now known
as the Syrtis Major, and, through its disappearance and reappearance,
he discovered that the planet rotated on its axis, and roughly
determined a daily period of twenty-four hours. For the first time it
was known that Mars had a day and a night. As some doubts existed as to
the correctness of Huyghens's figures, Cassini in 1666 determined anew
the rotation period of Mars and found it to be twenty-four hours and
forty minutes. From the white polar caps, the study of which we first
owe to Maraldi, it was found that the tilt of its axis to the plane
of its orbit was very nearly the same as that of the Earth. As this
inclination determines the seasons, it was seen that Mars, like the
Earth, had its spring, summer, autumn, and winter. A polar flattening
was also observed which was slightly in excess of ours.
"To all forms of life of which we have any conception, two things in
Nature are vital, air and water." Has it an atmosphere? Without air
no change could take place. The Moon without air remains unchanged,
except what gravitation accomplishes in pulling down crater walls.
"With Mars it is otherwise. Over the surface of that planet changes do
occur, changes upon a scale vast enough to be visible from the Earth."
The first sign of change occurs in the polar snow cap. It dwindles in
size every two years (the time of a single revolution of Mars around
the sun). For nearly two hundred years these white polar caps have
been observed to wax and wane. As the Martian winter comes on in the
northern hemisphere, for example, the polar cap extends its borders to
the temperate zone. As summer comes on the snow cap is seen to dwindle
gradually away, till by early autumn it presents but a tiny patch a
few hundred miles across. Schiaparelli observed changes in tint which
he noticed were correlated with the seasons. In 1894 observations
were made continuously from early June till late in November. These
dates, in Mars, represent the last of April till the last of August.
During this time marked changes took place in the bluish-green areas
of the planet. A wave of seasonal change swept down from the pole to
the equator. The fact of this occurrence constitutes positive proof of
the presence of an atmosphere. In another way the evidence was shown.
A series of measurements of the polar and equatorial diameters of
Mars were made, and these indicated that a visible layer of twilight
atmosphere had been measured. This, Lowell explains by a diagram and
other data. It is found, according to Lowell's observations, that the
atmosphere is much freer from clouds than had been supposed. He shows
conclusively that it is much rarer than that of the Earth. Appearances
have been seen, however, which are best explained by assuming them to
be clouds.
During the opposition of 1892, Mr. Douglass, at that time an assistant
astronomer at the Lowell Observatory, made a special study of the
terminator of Mars.[2] A careful study of the terminator for almost
every degree of latitude was made, and 733 irregularities were
detected. Of this large number, 694 were not only recorded, but
measured; and of these, 403 were depressions, and 291 were elevations
of the surface. Many of these irregularities were supposed to be
clouds, but the arguments to support this attribution are too technical
to be presented here. Unmistakable clouds have also been seen moving at
a definite rate of speed, as if carried along by the wind.
"To sum up, now, what we know about the atmosphere of Mars: we have
proof positive that Mars has an atmosphere; we have reason to believe
this atmosphere to be very thin,--thinner at least by half than the air
upon the summit of the Himalayas,--and in constitution, not to differ
greatly from our own."
As to the existence of water on the planet, one has only to consider
the polar snow caps. In the height of the southern winter, the
polar cap of snow measures over two thousand miles across, covering
fifty-five degrees of latitude, with one unbroken waste of white. As
spring advances the snow begins to melt, disappearing rapidly as summer
comes on, and, as it melts, a dark band is seen bordering this edge. As
the snow recedes the dark band recedes. This band is, therefore, not a
permanent marking on the planet, but obviously water, the result of the
melting snow--an arctic sea, in fact. This band is irregular, varying
in width in different longitudes, as if the water filled up large areas
of depression. When finally the snow cap disappears, as it did for the
first time on record on the notable occasion of October 13, 1894, the
dark band, which had become thinner, disappeared also, leaving only a
yellow stretch of surface. An additional proof that this dark band is
water, was established by Professor W. H. Pickering, for he discovered
that the light reflected from its surface was polarized. The absurdity
of the suggestion that these white polar caps are not snow, but
congealed carbonic acid gas, is fully shown by Lowell.
The asymmetry of the outline of these snow caps is paralleled by the
irregularity of the Earth's polar caps. Glints of brilliant light
are seen to flash out from this region, as if produced by sunlight
reflected from a sloping surface. On comparing these flashes of light
with observations made by Green, in 1877, they were found to be in
the same place. Detached fields of snow were also observed below
the receding line, an evidence that these regions were at a higher
elevation. As before stated, on October 13, 1894, for the first time in
the record of polar observations, the southern polar cap disappeared
entirely. In this connection it may be of interest to observe that in
the United States, in the summer of 1894, the temperature ranged a few
degrees above the normal. (For this fact I am indebted to Professor
Cleveland Abbe, E. S. M.)