Myths and Marvels of Astronomy
untenable. The sun is presented to us as a mighty furnace, in whose
fires the most stubborn elements are not merely melted but vaporised.
The material of the sun has been analysed, the motions and changes
taking place on his surface examined, the laws of his being determined.
How, it might be asked, is the question of life in other worlds involved
in these researches? The faith of Sir David Brewster in the sun as the
abode of life being dispelled, how could discoveries respecting the sun
interest those who care about the subject of the plurality of worlds?
The answer to these questions is easily found. The real interest which
solar researches have possessed for those who are not astronomers has
resided in the evidence afforded respecting the sun's position as the
fire, light, and life of the system of worlds whereof our world is one.
The mere facts discovered respecting the sun would be regarded as so
much dry detail were they not brought directly into relation with our
earth and its wants, and therefore with the wants of the other earths
which circle round the sun; but when thus dealt with they immediately
excite attention and interest. I do not speak at random in asserting
this, but describe the result of widely ranging observation. I have
addressed hundreds of audiences in Great Britain and America on the
subject of recent solar discoveries, and I have conversed with many
hundreds of persons of various capacity and education, from men almost
uncultured to men of the highest intellectual power; and my invariable
experience has been that solar research derives its chief interest when
viewed in relation to the sun's position as the mighty ruler, the
steadfast sustainer, the beneficent almoner of the system of worlds to
which our earth belongs. It is the same with other astronomical
subjects. Few care for the record of lunar observations, save in
relation to the question whether the moon is or has been the abode of
living creatures. The movements of comets and meteors, and the
discoveries recently made respecting their condition, have no interest
except in relation to the position of these bodies in the economy of
solar systems, or to the possible part which they may at one time have
performed in building up worlds and suns. None save astronomers, and few
only of these, care for researches into the star-depths, except in
connection with the thought that every star is a sun and therefore
probably the light and fire of a system of worlds like those which
circle around our own sun.
It is singular how variously this question of life in other worlds has
been viewed at various stages of astronomical progress. From the time of
Pythagoras, who first, so far as is known, propounded the general theory
of the plurality of worlds, down to our own time, when Brewster and
Chalmers on the one hand, and Whewell on the other, have advocated
rival theories probably to be both set aside for a theory at once
intermediate to and more widely ranging in time and space than either,
the aspect of the subject has constantly varied, as new lights have been
thrown upon it from different directions. It may be interesting briefly
to consider what has been thought in the past on this strangely
attractive question, and then to indicate the view towards which modern
discoveries seem manifestly to point--a view not likely to undergo other
change than that resulting from clearer vision and closer approach. In
other words, I shall endeavour to show that the theory to which we are
now led by all the known facts is correct in general, though, as fresh
knowledge is obtained, it may undergo modification in details. We now
see the subject from the right point of view, though as science
progresses we may come to see it more clearly and definedly.
When men believed the earth to be a flat surface above which the heavens
were arched as a tent or canopy, they were not likely to entertain the
belief in other worlds than ours. During the earlier ages of mankind
ideas such as these prevailed. The earth had been fashioned into its
present form and condition, the heavens had been spread over it, the
sun, and moon, and stars had been set in the heavens for its use and
adornment, and there was no thought of any other world.
But while this was the general belief, there was already a school of
philosophy where another doctrine had been taught. Pythagoras had
adopted the belief of Apollonius Pergaeus that the sun is the centre of
the planetary paths, the earth one among the planets--a belief
inseparable from the doctrine of the plurality of worlds. Much argument
has been advanced to show that this belief never was adopted before the
time of Copernicus, and unquestionably it must be admitted that the
theory was not presented in the clear and simple form to which we have
become accustomed. But it is not necessary to weigh the conflicting
arguments for and against the opinion that Pythagoras and others
regarded the earth as not the fixed centre of the universe. The certain
fact that the doctrine of the plurality of worlds was entertained (I do
not say adopted) by them, proves sufficiently that they cannot have
believed the earth to be fixed and central. The idea of other worlds
like our earth is manifestly inconsistent with the belief that the earth
is the central body around which the whole universe revolves.
That this is so is well illustrated by the fate of the unfortunate
Giordano Bruno. He was one of the first disciples of Copernicus, and,
having accepted the doctrine that the earth travels round the sun as one
among his family of planets, was led very naturally to the belief that
the other planets are inhabited. He went farther, and maintained that as
the earth is not the only inhabited world in the solar system, so the
sun is not the only centre of a system of inhabited worlds, but each
star a sun like him, about which many planets revolve. This was one of
the many heresies for which Bruno was burned at the stake. It is easy,
also, to recognise in the doctrine of many worlds as the natural sequel
of the Copernican theory, rather than in the features of this theory
itself, the cause of the hostility with which theologians regarded it,
until, finding it proved, they discovered that it is directly taught in
the books which they interpret for us so variously. The Copernican
theory was not rejected--nay, it was even countenanced--until this
particular consequence of the theory was recognised. But within a few
years from the persecution of Bruno, Galileo was imprisoned, and the
last years of his life made miserable, because it had become clear that
in setting the earth adrift from its position as centre of the
universe, he and his brother Copernicans were sanctioning the belief in
other worlds than ours. Again and again, in the attacks made by
clericals and theologians upon the Copernican theory, this lamentable
consequence was insisted upon. Unconscious that they were advancing the
most damaging argument which could be conceived for the cause they had
at heart, they maintained, honestly but unfortunately, that with the new
theory came the manifest inference that our earth is not the only and by
no means the most important world in the universe--a doctrine manifestly
inconsistent (so they said) with the teachings of the Scriptures.
It was naturally only by a slow progression that men were able to
advance into the domain spread before them by the Copernican theory, and
to recognise the real minuteness of the earth both in space and time.
They more quickly recognised the earth's insignificance in space,
because the new theory absolutely forced this fact upon them. If the
earth, whose globe they knew to be minute compared with her distance
from the sun, is really circling around the sun in a mighty orbit many
millions of miles in diameter, it follows of necessity that the fixed
stars must lie so far away that even the span of the earth's orbit is
reduced to nothing by comparison with the vast depths beyond which lie
even the nearest of those suns. This was Tycho Brahe's famous and
perfectly sound argument against the Copernican theory. 'The stars
remain fixed in apparent position all the time, yet the Copernicans tell
us that the earth from which we view the stars is circling once a year
in an orbit many millions of miles in diameter; how is it that from so
widely ranging a point of view we do not see widely different celestial
scenery? Who can believe that the stars are so remote that by comparison
the span of the earth's path is a mere point?' Tycho's argument was of
course valid.[31] Of two things one. Either the earth does not travel
round the sun, or the stars are much farther away than men had conceived
possible in Tycho's time. His mistake lay in rejecting the correct
conclusion because simply it made the visible universe seem many
millions of times vaster than he had supposed. Yet the universe, even as
thus enlarged, was but a point to the universe visible in our day, which
in turn will dwindle to a point compared with the universe as men will
see it a few centuries hence; while that or the utmost range of space
over which men can ever extend their survey is doubtless as nothing to
the real universe of occupied space.
Such has been the progression of our ideas as to the position of the
earth in space. Forced by the discoveries of Copernicus to regard our
earth as a mere point compared with the distances of the nearest fixed
stars, men gradually learned to recognise those distances which at first
had seemed infinite as in their turn evanescent even by comparison with
that mere point of space over which man is able by instrumental means to
extend his survey.
Though there has been a similar progression in men's ideas as to the
earth's position in time, that progression has not been carried to a
corresponding extent. Men have not been so bold in widening their
conceptions of time as in widening their conceptions of space. It is
here and thus that, in my judgment, the subject of life in other worlds
has been hitherto incorrectly dealt with. Men have given up as utterly
idle the idea that the existence of worlds is to be limited to the
special domain of space to which our earth belongs; but they are content
to retain the conception that the domain of time to which our earth's
history belongs, 'this bank and shoal of time' on which the life of the
earth is cast, is the period to which the existence of other worlds than
ours should be referred.
This, which is to be noticed in nearly all our ordinary treatises on
astronomy, appears as a characteristic peculiarity of works advocating
the theory of the plurality of worlds. Brewster and Dick and Chalmers,
all in fact who have taken that doctrine under their special protection,
reason respecting other worlds as though, if they failed to prove that
other orbs are inhabited _now_, or are at least _now_ supporting life in
some way or other, they failed of their purpose altogether. The idea
does not seem to have occurred to them that there is room and verge
enough in eternity of time not only for activity but for rest. They must
have all the orbs of space busy at once in the one work which they seem
able to conceive as the possible purpose of those bodies--the support of
life. The argument from analogy, which they had found effective in
establishing the general theory of the plurality of worlds, is forgotten
when its application to details would suggest that not _all_ orbs are
_at all times_ either the abode of life or in some way subserving the
purposes of life.
We find, in all the forms of life with which we are acquainted, three
characteristic periods--first the time of preparation for the purposes
of life; next, the time of fitness for those purposes; and thirdly, the