Mars as the abode of life

Front matter

N V .. N

.^mlTA

1>:^ -^

Preface

In 1906 Professor Lowell was asked by the trustee of the Lowell Institute to deliver a course of lectures there upon the planet Mars. Eleven years had elapsed since, at the invitation of the former trustee, he had done the like. When the time came for their delivery unusual interest was manifested, the course proving the most thronged of any ever given before the Institute. So great was the demand for seats that the hall could not contain the crowd, and the lectures had to be repeated in the afternoons, to audiences almost as large.

The eight lectures were then published, with slight changes, in six papers in the Century Magazine^ and were subsequently wanted by Macmillan and Company for issuance in book form.

Though dealing specifically with Mars, the theme of the lectures was that of planetary evolution in general, and this book is thus a presentation of something which Professor Lowell has long had in mind and of which his studies of Mars form but a part, the research into the genesis and development of what we call a world ; not the mere aggregating of matter, but viii PREFACE

what that aggregation inevitably brings forth. The subject which Hnks the Nebular Hypothesis to the Darwinian theory, bridging the evolutionary gap between the two, he has called planetology, thus designating the history of the planet's individual career. It is in this light that Mars is here regarded : how it came to be what it is and how it came to differ from the Earth in the process.

The object of the founding of the Observatory at Flagstaff was the study of the planets of our solar system ; a subject it has now for fourteen years made its specialty, the site, chosen for the purpose, enabling it to prosecute this study to more advantage than is possible at any other observatory at present. From the data thus collected, light has been thrown upon the evolution of the planets as worlds, resulting in a thesis of which the present book is a preliminary presentation.

As in all theses, the cogency of the conclusion hangs upon the validity of each step in the argument. It is vital that each of these should be based on all that we know of natural laws and the general principles underlying them. Their truth can only be adequately appreciated by those able to follow the physical and mathematical processes involved, and for this the general reader has not the necessary technical education. Yet there are many, professional and unprofessional

PREFACE ix

alike, capable of comprehending provided the steps are made sufficiently explicit. It has seemed, therefore, worth the trying to attempt to write for both classes of the community in a single volume. To do this, the general text has been printed complete in itself, while the demonstrations of the several steps have been collected in a part by themselves with reference to the places in the text where they severally should occur. All illustrations of the planet Mars are by Professor Lowell.

Foreword

PAGE I

Part I Chapter

I. The Genesis of a World ....

Catastrophic origin ......

Meteorites .......

Meteorite worship . . . . . .

Meteoric constitution of solar system

Analogy of cataclysm to new stars (Novae)

The meteorites gravitate together, generating heat

Amount of heat depends on the mass of the body

' Substances vary with heat and pressure .

^ Mass the fundamental factor ....

Cooling . . . . .

Life-history depends on size ....

II Planetologic eras

II

Present aspects of the planets our guide .

Geologic part of planetology ....

Landscape the result of cooling

. 14

Mountains in proportion to mass

. 15

Volcanic phenomena .....

. 16

Relative roughness of Earth, Moon, and Mars .

. 16

Mountains absent on Mars .

Slant illumination .....

• 17

Importance to astronomers ....

• 17

Applied to Mars . . . . .

Not indicative of mountains ....

Two or three thousand feet limit of elevation on Mars

XI

Xll

CONTENTS

Internal heat of the three bodies

Darwinian theory of lunar origin

Confirmed by lunar surface .

Probable comparative internal heat of earth and

Continental and oceanic areas formed

Their distribution determined

True Martian message

Their relative size on different planets

Earth's oceanic basins permanent .

Their flooring attests it . . .

II. The Evolution of Life The origin of organic life Life an inevitable phase of planetary evolution Water essential to life ....

Seas the earliest home of mundane life Uniformity of paleozoic fossils Carboniferous plant life Light less and heat more then than now . Effect on the earth ....

Earth itself responsible for paleozoic heat . Earth, not sun, the motive force in evolution

paleozoic era .

A once cloudy Mars ....

Life outgrows the sea .

Effect of environment upon evolution Deep-sea life thought impossible fifty years ago Extinction of light Deep-sea life

Blindness ....

Phosphorescent organs .

Lesson of the fishing fishes Cosmic character of life

III. The Sun Dominant

Transition

Mars.

in the

CONTENTS

XV

PAGE

One species supplants all others .... 206

To die of thirst ....

End foreseen ....

Further phenomena

21 1

Speculation excluded .

Our hfe not unique

Martian life nearing its end .

Part II I

3- 4- 5. 6.

7- 8.

9- 10.

17. 18.

On Moment of Momentum ....

The Connection of Meteorites with the Solar System

The Heat developed by Planetary Contraction

The Heights of Mountains on the Moon

Heat acquired by the Moon

Surface Heat of Mars

The Boiling-point of Water on Mars .

The Paleozoic Sun ....

EiFect on the Earth of the Supposed Paleozoic Sun .

On the Influence upon the Climate of Carbon Dioxide

the Air ....

Atmosphere of Mars The Mean Temperature of Mars A Dust Storm on Mars Mars on the Cause of an Ice-age Tidal Effects ....

On the Visibility of Fine Lines .

Canals of Mars Position of the Axis of Mars

Index .

LIST OF ILLUSTRATIONS

PLATES I. On the Road to the Observatory

Frontispiece

OPPOSITE PAGE

II. Mars — 1905

III. Spectrogram of Moon and Mars showing the Water-

vapor Band ......

IV. Tw^o Photographs of London taken from a Balloon V. At the Telescope — Observing Artificial Planets

VI. The Lov^ell Observatory in Mexico

VIII. A Chinese Translation of Lov^ell's ** Mars'*

138 148

172 208 217 282

CUTS APPEARING IN TEXT

Morehouse Comet .......

Meteorite from Canon Diablo, Arizona (pitted by fusion) Meteorite from Canon Diablo, Arizona (surface polished) Cloud Effect on Jupiter .....

An Apple shrunk to show the Effect of Contraction Phase View of the Moon, Mountainous Surface on the Termi nator .......

Phase View of Mars, May, 1907

View of the Earth for Proportion of Land and Sea

Dust Storm on Mars .....

Two Views of the Earth as seen from Space

Two Views of Mars for Comparison with the Earth

A Part of the Moon's Face showing Ancient Sea-bottoms

View of Mars apportioning Dark and Light Areas .

View of the Moon at the Full, in Like Manner

PAGE

19 20 21 22 22

23 26 29 31 xvii

XVlll

LIST OF ILLUSTRATIONS

Model of a Brontosaurus ......

Plant Life in the Coal Measures — from a Fossil Specimen Plant Life of the Upper Devonian — from a Fossil Specimen

A Trilobite

Fossil Footprints of Amphibia

Deep-sea Fishes ; Challenger Expedition

Deep-sea Fish ; Challenger Expedition

Deep-sea Angler Fish ; Challenger Expedition

Deep-sea Fish ; Challenger Expedition

Two Views of the SoHs Lacus Region on Mars, One Hour Apar

The North Polar Cap of Mars at its Least Extent .

The South Polar Cap of Mars at its Greatest Extent

Drawing of Mars with Dark Belt girdling Snow during its Melting

Early Winter Snow Storm in the Northern Hemisphere of Mars

Merriam's Map of the San Francisco Mountain and Vicinity

The San Francisco Peaks . . . . ' .

Arizona Desert View ......

The Douglas Fir .......

Vertical Distribution of Climate on Mountains, showing how

Land-masses raise Temperature .

Diagrammatic Profile of the San Francisco and O'Leary Peaks

from Southwest to Northeast ....

Chart of Effect of Plateau on Tree Zones — Less Elevation Chart of Effect of Plateau on Tree Zones — Greater Elevation Diagrams of Two Craters with Axis of Greatest Cold N.N. W Comparative Sizes of the Earth and Mars with the Polar Caps

of Both in their Springtime Lines in the Dark Areas of Mars, proving that the Latter are

not Seas ......

Two Views of Mars with Parings on the Terminator

Map of North America, showing approximately the Area of Dry

Land at the Close of Archaean Time . Petrified Forest of Arizona .....

Another View of the Petrified Forest of Arizona Effect of the Spring Mist around the North Polar Cap of Mars

LIST OF ILLUSTRATIONS

XIX

A Section of the Canal Eumenides-Oicus terminating in the

Junction Trivium Charontis Canals in Dark Regions connecting with the Polar Cap Camera of the Lowell Observatory by which the Canals of Mars

were Photographed ....

Ascraeus Lucus, from which radiate Many Canals Single and Double Canals A Mass of Double Canals A Mass of Single Canals about Lucus Phoenicis Cartouche of the Ceraunius — from a Chart by Lowell . Time of Vegetation on the Earth — from a Chart by Lowell Sprouting Time of Vegetation on Mars — from a Chart by Lowell Luci Ismenii, revealing the Systematic Method in which the

Double Canals enter the Twin Oases .... The Moon, showing the Straight Wall and Rill to Right of Birt

— from a Drawing by Lowell, May, 1905 . Mercury — Drawings depicting the Irregular Character of the

Lines on the Planet differing entirely in Look from those on

Mars

A Corner of Mars, June 10, 1907

Arethusa Lucus, April 15, 1903, with Converging Canals from

the North Polar Cap Canals from the South Polar Cap of Mars Djihoun ......

Differentiation of the Ganges

Northeast Corner of Aeria, July 2-5, 1907 ,

The Carets of Mars ....

Mouths of Euphrates and Phison . •

150 153

154 156 160 160 161

174 180 182

193 195

197 203 205 209 212 213

PART I PLANETOLOGY

FOREWORD

UP to the middle of the nineteenth century, astronomy was busied with motions. The wanderings of the planets in their courses attracted attention, and held thought to the practical exclusion of all else concerning them. It was to problems of this character that the great names of the past — Newton, Huygens, Laplace — were linked. But when the century that has gone was halfway through its course, a change came over the spirit of the investigation; with the advance in physics celestial searchers began to concern themselves with matter, too. Gravitational astronomy had regarded the planets from the point of view of how they act ; physical astronomy is intent upon what they are.

One outcome of this more intimate acquaintance is the new study with which the present papers deal : the evolution of the planets regarded as worlds. Such research has to do not merely with the aggregation of material, but with its subsequent metamorphoses after it has come together. Planetology we may call this science of the making of worlds, since it concerns itself with the life-history of planetary bodies from their chemically inert beginning to their final inert end. It constitutes the connecting link in the long chain of evolution from nebular hypotheses to the Darwinian theory. It is itself neither the one nor the other, but takes up the tale where the one leaves off, and leaves it for the other to continue.

Chapter I

SO far as thought may peer into the past, the epic Catastrophic of our solar system began with a great catastrophe. °"^'"' Two suns met. What had been, ceased ; what was to be, arose. Fatal to both progenitors, the event dated a stupendous cosmic birth.

It is more than likely that one or both of the colliding masses were dark bodies, dead suns, such as now circle unseen in space amid the bright ones we call the stars. Probable this is, for the same reason that the men who have been far outnumber the men who are. It is not to be supposed that the two rovers actually struck, the chances being against so head-on an encounter ; but the effect was as disastrous. Tides raised in each by the approach tore both to fragments, the ruptured visitant passing on and leaving a dismembered body behind in lieu of what had been the other. That the stranger continued on its way is shown by the present moment of momentum of our system. For it is very small, and the fact can be proved to mean that after the encounter its matter still lay massed for the most part in a

Meteorites.

Meteorite worship.

single centre.^ Thus, what had been a sun was left alone, with its wreckage strewn about it. Masses large and small made up its outlying fragments, scattered through space in its vicinity, while a shattered nucleus did it for core. So much of its history we learn from the tiniest of its constituents now: the meteorites. To meteorites thus attaches a peculiar importance ; for they are Rosetta stones for the decipherment of what went before.

From time unreckoned, rocks have fallen out of the sky upon the Earth. Most of them are of stone, but some are nearly pure iron, mixed with a small amount of nickel. They are called meteorites. Twenty-six known elements have been found to occur in them, and not one element that is new. They thus betray a constitution cognate to the Earth's.

In size these visitants vary from the grain-like bodies known as shooting-stars up to ponderous masses weighing many tons. Coming from space, they enter our air at speeds of from eleven to fortyone miles a second, and friction, due to their great velocities, fuses their exterior, and eats the holes with which is pitted what remains of them when they strike the ground.

Recorded meteoric falls date from a far past, and were deemed miraculous by early men. A stone that fell in Phrygia in pristine times was adored as Cybele,

" the mother of the gods," and later, about 204 B.C., was carted with great ceremony to Rome. The famous Diana of the Ephesians was probably none other than a meteoric stone, enshrined and worshipped as a goddess. Adoration of such arrivals from heaven was not of local observance only, but common to peoples over the whole Earth. There was a stone so worshipped at Mecca, and another in Tatar, Siberia, to which homage was paid ; while even in our own country a large mass of iron found in Wichita County, Texas, was set up as a fetich by the Indians, who revered it as a body not of the Earth, but sent to it by the Great Spirit.

A certain poetic justice invests this worship with a Meteoric

1 r ' r ^ i • i i i i constitution

grandeur or its own ; tor these thmgs are probably the ^^^^^^^ oldest bits of matter we may ever touch, the material system. from which our whole solar system was fashioned. They mark the farthest point in its history to which we can now mount back. The time of day at which they commonly fall — the afternoon rather than the morning — points curiously to their oneness with the rest of the solar system ; for in the afternoon the Earth looks backward over its traversed path, and their descent then proves that they follow and overtake it, and therefore that their movement has the same sense as its own. Still more conclusive of their relationship to ourselves is the speed with which they arrive, or, to be precise, the lack of it. For, did they come from the depths of space, were they ronins of the sky owing attraction's allegiance to no one lordly sun, they would have velocities exceeding forty-five miles a second, and these should often show, not an instance of which has ever been remarked.^

Just as, chemically and gravitationally, they stand confessed our kith and kin, so, physically, they betray the character of their origin; for they. bear in them occluded gases, which could have come there only under great pressure, such as would exist in the interior of a giant sun. Thus they proclaim themselves clearly fragments of some greater body. To the sometime dismemberment of this orb, from which disintegration our sun and planets were formed, the little, solitary bits of rock thus mutely witness.

Of the cataclysm that thus occurred far down the otherwise unrecorded vista of time, we have an analogue in the Novae that now and then blaze forth in the sky to-day, startling us from out the depths of space. These new stars, that suddenly appear, grow in brightness, and then slowly fade to nebulosity, speak by such action of a like catastrophe by which they were born again. Not otherwise was our own The meteor- ^'^^^^ hcraldcd in heaven.

ites gravitate

together, Strcwn thus about the scene of the encounter, the

heat^^ " pieces of the disrupted sun would begin to gravitate

Analogy of cataclysm to new stars (Novae).

together. The several subsidiary swarms of these fragments were of different sizes, but of much the same substance, because of the general similarity of their origin.

Cooled by contact with the cold of space, so soon as the meteorites started to fall together, they generat ed heat, warming one another, just as the rubbing of two sticks strikes fire.

The amount The Morehouse Comet as photographed at the

f, , Lowell Observatory, 1908

of heat pro- By E. C. Slipher.

duced depended upon the number of particles concerned, or, in other words, upon the mass of the body the particles were busied to form.

Approximately we can compute what this heat would Amount of be. If the body be supposed homogeneous, and to "j^the^mass^ contract under its own gravity from an original ex- of the body. tended condition to an eventually compressed state,

Substances vary with heat and pressure.

the work done, converted into heat, would be proportionate to the square of the mass divided by the radius attained. The same would be the case if the body were heterogeneous and composed of concentric spherical shells, only that the numerical amount would be greater according to the distribution of the mass. However the body were constituted, its caloric would be spread through the mass, and the resulting heat on each unit of it would therefore be as its mass divided by its radius. The internal temperature of the particular planet would therefore depend upon the amount of material that collected together. Thus each body was subjected to a different heat as well as to a differing pressure, according to its mass from the moment it began to form ; and to its mass alone, for that determined the radius to which it finally stood compressed.^ '

Now, all substances behave differently according to the temperature and the pressure under which they exist, both as to physical state and in their display of chemical action. Diverse results ensue from diverse conditions. The same element melts or remains solid, combines with another eagerly to form a third utterly unlike both, or coldly stands aloof from all association, solely as the temperature or the pressure constrains it to that end. Each, too, is a law unto itself, and acts unlike its neighbor as these compelHng causes change.

To them, therefore, diversity is due ; and they in their turn are conditioned by the mass.

Mass, then, is the fundamental factor in the whole Mass the evolutionary process, the determining departure-point, ^"^^'"'^"^^^ fixing what the subsequent development shall be. Though the bodies were in essence the same at the start, their initial quantity would change their very quality as time went on. What started like would become different ; for the gathering together of the particles into a single body was the preface to that body's planetary career.

Not until the internal heat began to abate did what we call evolution set in. Up to then the growing temperature induced a devolution or separating into simplicity of what had been complex. The time taken by each planet to reach its maximum bodily heat differed as between one and another. The larger the body, the slower it attained the greatest temperature of which it was capable, both by reason directly of its mass, and indirectly of the pressure to which that mass gave rise.

At its heat-acme the picture each planet presented Cooling. was all its own. Some may have been white-hot, some certainly were red-hot, some were merely darkly warm ; for one differed from another in self-endowment of warmth or light, each with a glory of its own.

Radiation had, of course, been going on from the time the impact of the particles began. At first the heat gained by contraction surpassed that radiated

away, but at last a time came when the depletion exceeded the generation of heat, and the planet began to cool. By parting with its caloric into space, its surface fell in temperature. Unlike in amount of acquisition, the bodies were no less unlike in the manner of their loss.

Each acted according to its kind. Those '^^^^^m^^^' . that originally had lit-

tle, lost that little fast ; for volume is a matter

Meteorite from Canon Diablo, Arizona

■D-,,Au r • • . • .1, .u> of three dimensions,

ritted by fusion m traversing the earth s

atmosphere. SUrface of but tWO,

and as through their surfaces their volumes cooled, the smaller got rid of their heat with relatively greater speed. Just as if two stones be put into the fire and then taken out, the smaller will turn cold while the larger is yet warm. With the

II depends on size.

planets, contrast in performance was accentuated from the fact that the big ones were intrinsically hotter at the start. Thus, for two reasons, the large Hngered in the race : they had more to lose, and they lost it more reluctantly.

In consequence the life-history of a planet was long Life-history or short in proportion to its size. If little, it ran through its gamut of change fast, and that gamut was itself brief; if large, it tarried in its several stages, and those stages were themselves drawn out. But, in addition to this, the larger knew states the smaller in their heating had never reached. Diversified age, both in length of years and in breadth of experience, was thus the first result of size.

Six stages may conveniently be distinguished in the progress of a planet from sun to cinder, all of which will be traversed by the body, if it be sufficiently big. If it be of asteroidal size, it

virtually knows none of them, remaining meteoric from first to last. The six periods may be designated : — i%

■.I^KiMi4

M

Hp m

«J

Planetologic eras.

Meteorite from Canon Diablo, Arizona Surface polished. Showing method of crystallization.

I. The Sun Stage. Hot enough to emit light. II. The Molten Stage. Hot, but lightless. III. The Solidifying Stage. Solid surface formed. Ocean basins determined. Age of Metamorphic rocks.

IV. The Terraqueous Stage. Age of sedimentary

rocks.

V. The Terrestrial Stage. Oceans have disappeared. VI. The Dead Stage. Air has departed.

Present Though wc cannot in our own ephemeral life watch

aspects of the , 111 11 r •

planets our ^^7 pl^^^t pass through thcse several phases or its s"^^^- y^^ ^"\ career, we can get a view of the

process by studying the present conditions of the various planets and piecing together the information we thus obtain. It is, in the Cloud^e^cton end, as conclusive as in botany Jupiter would be the studv of a wood

As observed at the I.owell

observatory in 1907, by Carefully noting the condition

indicating that Jupiter r r\ * j • • j 1 ^ • ^u •

. . ^^ J 1 . or the mdividual trees m their

IS m the second planeto-

logic stage. various growths from seedling

to patriarch. Thus, at the present moment, in Stage II are found Neptune, Uranus, Saturn, and Jupiter; in Stage IV, the Earth; in Stage V, Mars; and in Stage VI, the Moon and the larger satellites of the other planets.

Each planet's internal heat was its initial motivepower, and cooling the mode by which this energy worked, first, to the fashioning of its surface, and then to all evolution upon it. While still in the molten state the mass was a seething chaos but little differentiated from any other equal agglomeration of matter. Yet even here the several substances had begun to segregate, the heavier falling to the bottom, the lighter rising to the top.

With Stage III we enter the part of a planet's Geologic career with which, on our Earth, geology is concerned. ^^,^ ° ,

■' -'00-' planetology.

Though specifically the story only of our Earth, that science has analogues elsewhere, and to be best understood needs to be generically considered. Local as many Earth-happenings are, with increasing light from the heavens it is becoming clear that the main events are of cosmic occasioning, and that astronomic cause presides over their manifestations. Initial instance of planetary action occurs at the first stage of the Earth's history to which geology mounts back — that in which a crust began to form over the molten mass. The liquid metal in a furnace upon which the solidifying slag has begun to float gives us an idea of this early state of things. Our metamorphic rocks were in action akin to the furnace slag, rising to the surface because of their lightness. Proof of this lies in their present density, which is only about one-half of the average

Landscape the result of cooling.

density of the Earth, 2.7 times that of water instead of ^.^. Their constitution furnishes further evidence that such they were. The gneiss, mica, and hornblende of which they are composed show by their crystalline form that they cooled from a once molten state, and their foliation indicates that they were crumpled and recrystallized in the process.

In Stage III the body first acquires a physiognomy of its own. Up to then it is a chaotic mass as unstable: and shifting as clouds in the sky ; but at the advent of surface solidification its features take form — a form they are in fundamentals ever afterward to keep. Its face is then modelled once for all ; and its face is the expression of its character. Our knowledge of this stage and of the two subsequent stages IV and V is derived from study of three planets of our system; the Earth, the Moon, and Mars. The others contribute nothing to our information of these mid-phases, eitherbecause, like Mercury and Venus, they are too advanced, or because, like the major planets, Jupiter,, Saturn, Uranus, and Neptune, they are not advanced, enough.

Landscape is simply the sculpturing due the fashioning cause of planet physiognomy. As the substances composing the mass cool, some of them expand ; but most of them contract, and in consequence of this the crust finds itself too large for what it encloses.^

To fit the shrunken kernel it must needs crumple into folds. These folds are what we know as mountain ranges — long, low swells while the crust is yet thin, abrupt and broken fractures when it has become thick. The valleys between mark the down-folds of the squeeze.

Wrinkles are thus as inevitable a consequence of planetary aging as of man's, only that while they are thought a disfigurement in him, they are regarded as beautiful in a world.

Such crinkling of its cuticle is most pronounced where the heat to be got rid of is greatest, and the surface to radiate it is relatively least. Both conditions are fulfilled the more completely the bigger the body. The larger the planet, therefore, the more mountainous its surface will be when it reaches the crumphng stage of its career.

An Apple, shrunk to show the Effect of Contraction

Mountains in proportion to

Volcanic j^ Hke manner is volcanic action relatively increased,

phenomena.

and volcanoes arise, violent and widespread, in proportion ; since these are vents by which the molten matter under pressure within finds exit abroad. This is shown in their positioning. They occur where the crust is most permeable, and so are found along the edges of continents, as these are weakened by dipping down into the sea.

Relative Three bodies exist near us in space where the work-

Earth Moon ^"g ^^ ^^^^ inevitable action stands displayed, and its and Mars. Comparative effects may thus be studied : the Earth, Mars, and the Moon. With the accidented character of the Earth's surface we are all famihar. Its mountains, its volcanoes, and its hills go to make up its loveliest and its grandest features. Its mass fashioned them, and fashioned them as they are because its mass was large. This mass is nine times that of Mars, and eighty-one times that of the Moon. Being greater than that of the Moon or Mars, our globe should have crumpled more, and those other two bodies should have smoother contours than the Earth shows. The general order of their roughness should be Earth, Mars, Moon.

No mountains Now, whcn wc comc to scan Mars with nicety, we

on Mars. in i r • t • r '

^TQ gradually made aware or a curious condition or its surface. It proves singularly devoid of irregularity. The more minutely it is viewed, the more its levelness grows apparent. Finally, calculation shows that i

heights, even of very moderate elevation, should be j