The idea that intelligent but nonhuman living beings might exist somewhere has tantalized the minds of men since the dawn of recorded history. Virtually every civilization or major culture on Earth has entertained some such speculation, whether in its mythology, its religious or scientific writings, or in its philosophy of nature.

The sophisticated concept of aliens indigenous to planets circling faraway stars did not blossom into existence overnight, however. The theme of extraterrestrial life has slowly evolved over the course of many millennia of pensive human contemplation. Before it was accepted that Earth was a mere planet and that many others could exist, intelligent nonhuman beings were commonly viewed in a mythological context. But as man learned to appreciate the vast scale of the universe, the idea of life in the physical cosmos matured and gained wider currency.*

* There are many good historical introductions to both the scientific^{747, 1754, 1769, 1872} and the fictional^{1896, 1897, 1872} literature.

While it is often pointed out that aliens appear in the most ancient of human records, the true antiquity of the idea is rarely appreciated. An excellent example comes from the Sumerian civilization, which flourished more than five thousand years ago (and may well be the most distant ancestor of Western culture). According to Sumer legends which have survived, codes of law, science, art, architecture and the essentials of proper social behavior all were given to the humans by alien teachers — amphibian intelligent animals with fishy heads and torsos and human feet. These creatures are never described as gods; there is little doubt the Sumerians presumed them to be as mortal as their human students.²⁰

Usually, though, ancient gods were seen as superior beings with celestial abodes. The Babylonians, successors to the Sumerian civilization, held that the moving points of light in the sky which are the planets were the homes of their gods.⁴⁵ Other cultures such as the Eskimos believed that the Moon and other heavenly objects were themselves gods.¹⁸⁷²

Supposing the world to be flat and subscribing to the nontheistic Confucian philosophy, the venerable Chinese had no conception of or need for life in the firmament — although dragons and other monsters appeared frequently in the literature. The holy books of Buddhism, on the other hand, appear to accept the plurality of worlds in countless numbers, complete with indigenous alien plant and animal lifeforms.¹⁸⁹⁸

The ancient Vedda culture, which prospered on Ceylon prior to the Hindu invasion in the 6th century B.C., held that after death souls migrated to the Sun, Moon, and the stars before reaching Nirvana (the ultimate state of perfection). The beliefs of the Hindus are also closely associated with the idea of a plurality of worlds. The Indian philosophy, in fact, "explicitly assumes the existence of extraterrestrial intelligences."¹⁸⁹⁹  In one myth, as told in the Brahmavaivartcz Purana of the god Indra, we find:

Hold! I have spoken only of those worlds within this universe. But consider the myriads of universes that coexist side by side, each with its Indra and Brahma, and each with its evolving and dissolving worlds … Can you presume to know them, count them, or fathom the reaches of all those universes with their multitude of worlds, each with its legions of transmigrating inhabitants?¹⁹⁰¹

The Old Testament is filled with strange events which some have argued may be linked with extraterrestrial visitations — such as the visions of Ezekiel.¹⁰⁵⁸ And in the New Testament appear such positive statements as: "In my Father's house there are many mansions" (John 14:2), and so forth.

But by far the most important early contributors to the advancement of the idea of ETs were the Greek and Roman cultures. To the Homeric Greeks, the Moon was an inhabited world separate from Earth, the dwelling place of protean gods and the spirits of departed humans.¹⁷⁵³ Traditional Grecian mythology held that the universe created the gods, a view more consistent with the concept of mortal, fallible aliens than the usual creator-deity of other religions.

The Greek culture inherited considerable astronomical knowledge from the Egyptians and Babylonians upon which much speculation could be based. Thales of Miletus (6th century B.C.) was a philosopher who had guessed that heavenly bodies might have a material composition similar to that of the Earth. Around this time Pythagoras (well-known for his contributions to geometry) and others were beginning to think of Earth as a globe in space — a sharp break from the flat-world concepts of earlier thinkers.

Since other earthlike worlds might therefore exist, Xenophanes of Colophon — a contemporary of Pythagoras — populated the Moon with inhabitants, cities and mountains.⁶⁰² Another Greek philosopher named Anaximenes evidently also believed in a multitude of celestial habitats, because he had the audacity to tell Alexander the Great that the Macedonian king had conquered "only one of many worlds."⁷⁰²

In the 5th century B.C. Democritus taught the concepts of infinite space and numerous worlds.⁷⁴⁷ One of his pupils, Metrodorus of Chios, later wrote that "to consider the Earth the only populated world in infinite space is as absurd as to assert that in an entire field sown with millet only one grain will grow."²⁰ Anaxagoras too embraced the plurality of worlds: "The Sun, the Moon, and all the stars are stones on fire. The Sun is a red-hot mass, or a stone, on fire. The Moon is of earthy nature … an incandescent solid, having in it plains, thountains, and ravines!" ¹⁸⁷²

Another 5th century mathematician of the Pythagorean school stated his views on extraterrestrial most forthrightly:

The Moon has an earthy appearance because, like our Earth, it is inhabited throughout by animals and plants, only larger and more beautiful than ours: for the animals on it are fifteen times stronger than those on the Earth … and the day in the Moon is correspondingly longer... ¹⁸⁷²

And from The Travels of the Young Anacharsis in Greece, written sometime during the 4th century B.C., we have:

As nature is even richer by the variety than by the number of the species, I spread in the various planets … peoples who have one, two, three, or four senses in supplement. I then compare their geniuses with those Greece has produced, and I must confess that Homer and Pythagoras inspire my pity." ³⁶²

About this time the first "Moon romance" was written by Antonius Diogenes. His Of the Wonderful Things beyond Thule  included a visit to the Moon; unfortunately, the original text has not survived.¹⁸⁷²

The Roman poet and philosopher Lucretius firmly believed in a host of inhabited worlds. As he wrote in De Rerum Natura:

Why then you must confess that other worlds exist in other regions of the sky, and different tribes of men, kinds of wild beasts.... Nothing in nature is produced alone, nothing is born unique, or grows unique, alone. Each thing is always specimen — of race or class, and many specimens belong to each.... That sky and Earth and Sun and all that comes to be are not unique but rather countless examples of a class." ⁷³³

Unfortunately for xenology, the Earth-centered (geocentric) cosmologies sponsored by Plato and Aristotle held sway. Both philosophers were firmly opposed to the concept of a plurality of worlds. Aristotle asserted that all matter was contained in this world, thus leaving no room for any others. The unchangeability of the heavens was cited as additional proof of this.⁴⁵ These teachings were later picked up by the Christian Church and enforced as law. It was then denied that any knowledge could exist that Aristotle had not known.

Despite the powerful forces arrayed behind the Aristotelian world view, it took time to halt the intellectual momentum in favor of habitable worlds. The famous Roman poet Cicero was interested in the possibility of living beings on the Moon, and his Somnium Scipionis may have inspired Plutarch (46 A.D. - 120 A.D.) to write his account of a visit to the Moon. In Facies in Orbe Lunare, after dealing with various problems involved in reaching the Moon, the Greek historian endorsed the Pythagoreans thus: "They affirm that the Moon is terrestrial and inhabited like the Earth, peopled with the greatest living creatures and the fairest plants..."¹⁷⁵³ He continues:

It is possible that some inhabitants exist on the Moon; and those who claim that these beings must need everything that is necessary to us, have never considered the variety that nature offers so that animals differ amongst themselves more than they differ from inanimate life.

Only forty years after the death of Plutarch, the Greek satirist Lucian of Samosata (125 A.D. - 190 A.D.) wrote the first interplanetary romance that has survived the ravages of time.¹⁸⁷² In his elaborate True History Lucian and his fellow travelers are carried by whirlwind to the Moon, found to be inhabited by a race of men who ride on the backs of three headed birds. The adventurers have arrived at a most inopportune moment, as the Lunarians are in the middle of a war with the inhabitants of the Sun to settle a dispute over the colonization of Venus.¹⁷⁵³ The space troops include such marvelous creatures as "Horse-vultures," "Salad-wings," and "Flea-archers" (archers astride giant lunar fleas).⁷⁴² The story is reminiscent of the "space opera" of the 1930's and 1940's.

But after Lucian there was no further debate of the possibility of visiting other worlds and meeting the indigenous lifeforms there — for more than a thousand years! This may probably be attributed to the pervasiveness of the Church philosophy and its rigid opposition to the idea of the plurality of worlds. The pronouncement of Franciscus Gratianus, Bishop of Chiusi, in 1145 A.D. was perhaps typical: The belief in many worlds was to be condemned as heresy.

Of course, there was a serious logical flaw in this stance. If God really was all-powerful, why was he only able to create one world? Conversely, if only one world existed how could God possibly be truly infinite and omnipotent? The theologian Thomas Aquinas (1225 - 1274) came up with a "solution" to the problem: God had the power to create infinite worlds, but all the matter in the universe had been used to construct Earth!³⁷²

Despite the obvious holes in this reasoning, the Church subsequently partially reversed its extreme position. In 1277, under the authority of the Pope, the Bishop of Paris decried as new heresy the belief that a plurality of worlds was impossible!⁴⁵ This did not, of course, mean that the Church began to teach the plurality of worlds. According to the physics of Aristotle, still in vogue until the 16th century, if any other worlds did exist they would have to gravitate to the center of the universe (where Earth was). But it became wrong to suggest that God could not create many worlds if He wished.⁷⁴⁷

The debate was far from ended. In 1410 the Jewish philosopher Crescas wrote: "Everything said in negation of the possibility of many worlds is vanity and a striving after wind." Still, he was unwilling to stick out his neck very far:

… yet we are unable by means of mere speculation to ascertain the true nature of what is outside this world; our sages, peace be on them, have seen fit to warn against searching and inquiring into what is above and what is below, what is before and what is behind...⁷⁴⁷

The first really explicit deviation from orthodoxy occurred during the Inquisition in Europe in the mid-fifteenth century. Cardinal Nicolas of Cusa, Bishop of Brixen and Christian philosopher, wrote a book called Of Learned Ignorance (1440) in which he stated:

Rather than think so many stars and parts of the heavens are uninhabited, and that this Earth or ours alone is peopled … we will suppose that in every region there are inhabitants, differing in nature by rank and all owing their origin to God.⁷⁴⁷

Considering how little we know about other animals here on Earth, he claims, "of the inhabitants … of worlds other than our own we can know still less, having no standards by which to appraise them."⁷⁴⁷ It is said that Cusa escaped the Inquisitional wrath only by virtue of his special protection and friendship with Pope Eugene IV.¹⁷⁵³

As astronomical observations became more accurate, the geocentric Aristotelian/Ptolemaic world view began to generate problems that were difficult to resolve. Calculated positions of the planets, for instance, were invariably in error. This necessitated the concoction of elaborate "explanations" based on a kind of astronomical fudge factor.

During this time the first tale of interplanetary travel since Lucian (thirteen centuries earlier) was published. Ludovico Athsto's (1474-1533) Orlando Furioso tells of a trip to the Moon using a chariot driven by Saint John. The vehicle is drawn by flaming horses, who leap from the summit of a high mountain. The Moon, it turns out, is littered with cities and townships. The heavy theological flavor of the story may have helped save Ariosto from persecution.

A mere eleven years later the first edition of Copernicus‘ renowned De Revolutionibus Orbium Caelestium appeared, proposing the modern Sun-centered (heliocentric) solar system. If the Holy See was enraged at this they could do nothing, for the Polish astronomer died the year his book came out — 1543.

Others were not so lucky. Forty one years after the death of Copernicus a Dominican monk by the name of Giordano Bruno (1547-1600) wrote his controversial On the Infinite Universe and Worlds. Among other things, the Italian philosopher advanced the following heterodoxies: "Innumerable suns exist; innumerable earths revolve about these suns in a manner similar to the way planets revolve around our sun. Living beings inhabit these worlds."²⁰

Although Bruno was visiting in relatively tolerant Great Britain at the time his book was published,⁷⁴⁷ as soon as he set foot on Italian soil he was promptly arrested by the Church and incarcerated without trial for seven years.⁴⁵ He was then convicted of heresy by a tribunal of the Holy See and sentenced to death. Bruno was burned at the stake in the Campo de' Fiori in Rome on February 17, 1600.

With the improvement of the telescope by Galileo (1564-1642) and the subsequent observations of the mountainous terrain of the lunar surface, it became clear that the Moon was quite similar to the Earth in many ways. His discovery of the four largest Jovian satellites confirmed the existence of many worlds. For his part in advancing the heliocentric Copernican astronomy and the hypothesis of the plurality of worlds, Galileo was arrested by the Inquisition and forced to recant his heresies. Luckily, he was not executed.

Johannes Kepler (1571-1630) further refined the Sun-centered cosmology by suggesting that planets move in ellipses rather than perfect circles. He also authored an engrossing fictional account of a trip to the Moon, published four years after his death, entitled Somnium. Lunar biology is described in some detail, including several forms of vegetation and serpentlike grotesque monsters.⁷⁴²

The first narrative of a trip to the Moon written in English was penned by Bishop Francis Godwin in 1638. In The Man in the Moone the main character, Domingo Gonsales, uses a team of trained geese under harness to carry him to the Moon whereupon:

Suddenly I saw myself environed with a kind of people most strange, both for their feature, demeanure, and apparel. Their stature was most diverse, but for the most part twice the height of ours; their color and countenance most pleasing, and their habit such as I know not how to express....¹⁸⁷²

By 1640 another book was out, a two-volume set by fellow English Bishop John Wilkins, entitled The Discovery of a World in the Moone. Wilkins asserted his straightforward belief "that it is possible for some of our posterity to find out a conveyance to this other world, and if there be inhabitants there, to have commerce with them."⁷⁴⁷

The roadblocks to the idea of intelligent alien life on other worlds were rapidly disintegrating.

By the early and mid-1600's the utilization of the Moon and other planets as abodes for extraterrestrial life had become an accepted theme, certainly in fiction but also increasingly in scientific writings of the time. In the 17th century — the century of great discoveries, scientific breakthroughs and grand geographical voyages around the world — more than 200 accounts of trips to the Moon appeared in print.¹⁸⁹⁶

In 1656 the Jesuit Athanasius Kircher sent his hero touring the heavens with an angel as his guide. In the course of these journeys, the Moon was found to be quite habitable, including mountains, oceans, lakes, islands and rivers.¹⁸⁷²

About a decade later in Milton's well-known Paradise Lost, the angel Raphael discusses the possibility of life on the Moon and other planets. Says he of the Moon:

Could not there be
Fields and inhabitants? Her spots thou seest
As clouds, and clouds may rain, and rain produce
Fruits in her softened soil, for some to eat
Allotted there; and other Suns, perhaps,
With their attendant Moons…

But Adam is cautioned that it is dangerous to cogitate such matters, as they are best left to the Almighty: "Dream not of other worlds, what creatures there live, in what state, condition or degree."⁷⁰²

David Russen in A Voyage to the Moon (1703) allowed that there might be inhabitants on the Moon, but that traveling there would be difficult because of the lack of air between worlds.⁷⁴² In Robert Paltock's John Daniel (1751), a survivor of a shipwreck constructs a flying machine to escape his island prison but winds up escaping the Earth instead! On the Moon he finds copper-skinned humanoids who live in caves and worship the Sun.⁷⁴² And in 1775, a Frenchman named Louis-Guillaume de la Follie published an account of the doings of beings on Mercury. In Philosophy Without Pretension, a brilliant Mercurian inventor-scientist constructs a flying machine which carries a skeptical fellow scientist to Earth and maroons him here.⁴⁵

But the fictional treatments of extraterrestrial life in the late 17th and 18th centuries were executed with a growing eye to satire and witty criticism of the foibles of modern civilization. Despite the increasing interest among the scientific community in alien life, fictional tales remained remarkably free of science and technical accuracy.

For example, two of the best-known early adventure stories were Cyrano de Bergerac's (1620-1655) Voyage to the Moon (1657) and History of the States and Empires of the Sun (1662) (which was uncompleted at his death) . In the first of these tales, the narrator wears bottles filled with morning dew which are attracted to the Sun — everyone knows dew rises! — and eventually transport him to the Moon. There he meets Domingo Gonsales and his trained geese, and the lunar queen and her court are a cruel mockery of the monarchy of contemporary England.¹⁸⁷²

Gabriel Daniel's novel A Voyage to the World of Descartes (1694) is a satire on the dualist philosophy of Descartes. Daniel's travelers found the Moon to be inhabited only by spirits.⁷⁴² Voltaire's characters in Micromegas (1752) are extraterrestrials: One is a dwarf from Saturn with 72 different senses, and the other is a giant eight leagues tall from the Sirius star system possessing more than a thousand different senses. The story is a satire on the supposed intelligence of mankind, as it might be evaluated by objective aliens.⁷⁴² And Aratus' narrator in his A Voyage to the Moon (1793) treks to Luna by hot air balloon, landing on an island peopled with lipedal snake-like organisms that speak English. The book caricatures British social and political life by describing the civilization of the man-snakes in a most derogatory fashion.⁷⁴²

Another main thrust during this era of development was along religious lines. As the astronomers during the 1600's came to accept the plurality of worlds, an assumption arose that God would never knowingly "waste" a world.⁷⁴⁷ This view, which persisted well into the 19th and even 20th centuries,^{95, 103, 117, 206, 599} held that if worlds did exist in space their only real purpose could be to harbor manlike beings.¹⁹⁰²

In this vein, Ralph Cudworth wrote in The True Intellectual System of the Universe (1678): "It is not reasonable to think that all this immense vastness should lie waste[d], desert[ed], and uninhabited, and have nothing in it that could praise the Creator thereof, save only this one small spot of Earth."⁷⁴⁷ The Anglican theologian Thomas Burnet followed suit six years later in a book called The Sacred Theory of the Earth, wherein he asked:

God himself formed the Earth … he formed it to be inhabited. This is true, both of the Earth and of every habitable World whatsoever. For to what purpose is it made habitable, if not to be inhabited? We do not build houses that they should stand empty, but look out for Tenants as fast as we can.⁷⁴⁷

In a sermon preached by a young English clergyman named Richard Bentley in 1692, we find still more evidence of the new viewpoint that swept over Christianity in only a century: "It remains, therefore, that all bodies were formed for the sake of intelligent minds … each for their own inhabitants which have life and understanding."⁷⁴⁷ William Derham, another minister and author of the popular work Astrotheology (1715), was of the same opinion.

Nor was colonial America immune to these new exotheological conceptions. Cotton Mather (1663-1728), a Puritan minister who wrote a book called The Christian Philosopher, had this to say: "Great God, what a Variety of Worlds hast thou created! How stupendous are the Displays of thy Greatness … in the Creatures with which thou hast replenished those Worlds!"*⁷⁴⁷ During this entire period of literary and theological development, scientific speculation on the nature of extraterrestrial life was on the upswing. Spaceflight to other worlds was no longer viewed as wholly impractical; when Peter Heylyn compiled his World Geography, the Moon was described along with such other "imaginary" lands as Australia, New Guinea, and the Solomon Islands.¹⁸⁷²

Bernard de Fontenelle's Conversations about the Plurality of Worlds came out in 1686 and was an instant success. Not only did de Fontenelle conclude that intelligent beings must exist on worlds other than Earth, but he advanced the progressive notion that such beings would have those characteristics consistent with the environment of the world in which they lived.

Mercurians, therefore, were all hotheads in temperament. The inhabitants of Venus, the next planet out from the Sun, "resemble the Moors of Granada, a small, black people, burned by the Sun, full of wit and fire, always in love, writing verse, fond of music, arranging festivals, dances and tournaments every day." Jupiterians rarely encountered each other, since their planet was so large, and the extreme coldness of Saturn rendered the creatures there dull, torpid and sluggish in mind and body. It was suggested that the Moon might not be inhabited at all, because of the thinness of the atmosphere.¹⁹⁵⁰

The first full-length scientific book to deal seriously and specifically with the problem of extraterrestrial life was authored by the Dutch physicist and astronomer Christian Huygens. Entitled The Celestial Worlds Discover'd (1698), it contained many detailed theories and pursued with greater diligence the conform-to-the-environment theme de Fontenelle had also wrestled with.

Of the planet Mars, for instance, Huygens cautiously states: "His Light and Heat is twice, and sometimes three times less than ours, to which I suppose the Constitution of his Inhabitants is answerable." As for populating the Sun,** Huygens (unlike William Herschel more than a century later) is very pessimistic:

That the Sun is extremely hot and fiery, is beyond all dispute, and such Bodies as ours could not live one moment in such a Furnace. We must make a new fort of Animals then, such as we have no Idea or Likeness of among us, such as we can neither imagine nor conceive: which is as much to say, that truly we have nothing at all to say.⁶⁰²

Many 18th century notables freely gave their views on alien life. Emanuel Swedenborg (1688-1772), a Swedish scientist, mystic philosopher and theologian, fancied that Venus was inhabited by two distinct species of giants — one the gentle, religious, human herdsmen, and the other the cruel, savage plunderers "whose favorite sport is eating what has been stolen."⁴³

In a more serious temper, in 1728 Benjamin Franklin wrote: "I believe that Man is not the most perfect Being but One; rather that as there are many degrees of Beings his Inferiors, so there are many degrees of Beings superior to him."⁷⁴⁷ The so-called father of Russian science, Mikhail Vasilievich Lomonosov (1711-1765), published many poems of both satirical and scientific bent to communicate his belief in life on other worlds to his countrymen. And John Adams, who became the second President of the United States, made the following entry in his personal diary on April 24, 1756: "… all the unnumbered Worlds that revolve round the fixt Stars are inhabited, as well as this Globe of Earth."

Legal philosophers likewise expressed interest in xenology at an early date. For example, Immanuel Kant's Universal Natural History and Theory of the Heavens (1755) set forth the then unorthodox proposition that while many worlds may be inhabited, not all planets will bear life. Furthermore, Kant felt it likely that "celestial bodies which are not yet inhabited will be hereafter, when their development has reached a later stage."

The great French philosopher Montesquieu (1689-1755) may be credited with the anticipation of modern metalegal concepts (see Chapter 25). He envisioned the possibility of humans having some form of legal relations with intelligent ETs. In his De l‘espirit des lois (1748) he stated:

Laws in the broadest sense imply relationship. That necessarily follows from the nature of things. In that sense all beings have their laws… Laws are relationships which exist between it and the different beings as well as the relations between these beings themselves.³⁷²

And back across the English channel, the British political leader Lord Bolingbroke (1678-1751) wrote that ours may not be the highest intellect in the universe. In fact, said he, "we may well suspect that ours is the lowest, in this respect, of all mundane systems."⁷⁴⁷

* A curious book was written in 1757 by Dr. Swinden, a British clergyman, called Researches on the Nature of the Fire of Hell and the Place Where It Is Situated. According to Swindon's detailed calculations, the interior volume of Earth is far too small to hold the multitude of angels that fell from Heaven after the Great Battle. Hence, the Sun is the only possible abode of the devil, it being a well-sustained fire and having plenty of room for Satanic inhabitants.

** The theory of solar-dwellers was once used as evidence at a murder trial. One Dr. Elliot, accused of the murder of Miss Boydell in 1787, stated in open court his opinion that the Sun was endowed with intelligent inhabitants. His friends asserted insanity as his defense, citing as clear proof his beliefs regarding life in the Sun.⁴³

In the early 19th century it was still maintained by many that the Moon must be inhabited, or else God's work would be wasted. Thomas Dick carried this idea to its absurd but logical conclusion in his nonfiction theological work entitled Celestial Scenery (1838). First, he noted that the rings of Saturn contain an area of more than thirty million square miles. "It is not likely," he went on, "that the Creator would leave a space equal to nearly six hundred times the habitable parts of our globe, as a desolate waste, without nay tribes of either sensitive or intelligent existence …"¹⁸⁷²

By the mid-nineteenth century this view remained virtually unchanged. Father Angelo Secehi, a Jesuit astronomer, asserted of the planets: "These worlds are bound to be populated by creatures capable of recognizing, honoring and loving their Creator."¹⁹⁰⁵

But as the last century drew to a close, the English poetess Alice Meynell (1849-1922) sounded in verse what was to become the less-chauvinistic modern perspective:

Doubtless we shall compare together, hear
A million alien Gospels …
O, be prepared, my soul!
To read the inevitable, to scan
The million forms of God those stars unroll
When, in our turn, we show to them a Man.⁷⁰²

This idea that ETs will have their own religions and their own gods has replaced "waste" as the central topic of exotheological debate.

Scientific speculations were often grossly unreliable and misleading, as evidenced by the "Moon Hoax" fiasco. In July of 1822 a German astronomer by the name of Franz von Paula Guithuisen had first reported observing a great walled city on the Moon, near the crater Schröter on the lunar equator. This caused quite a flap, and the stage was set.

The famous British astronomer Sir John Herschel (1792-1871) traveled to the Royal Observatory at Capetown, South Africa in 1834 to commence a full sky survey of the Southern hemisphere. The project was well known throughout the educated world at the time and, added to Gruithuisen's wild claims, may explain the widespread acceptance of Richard Adams Locke's concocted front page story on Sir Herschel's "amazing discovery" of inhabitants on the Moon.

Published in The New York Sun during the first week of September, 1835, the report (called "Great Astronomical Discoveries") claimed that Herschel had turned a powerful new telescope towards the Moon and had observed life there, including forests, bison-like animals, blue unicorns and finally, winged men and women:

We counted three parties of these creatures, of twelve, nine, and fifteen in each, walking erect towards a small wood near the base of the eastern precipices. Certainly they were like human beings, for their wings had now disappeared, and their attitude in walking was both erect and dignified.¹⁸⁷²

The entire first reprinting of 20,000 copies was completely sold out on the day of publication.

During the second half of the 19th century the French scientist and popularizer Camille Flammarion wrote many discourses on the subject of extraterrestrial life. His On the Plurality of Habitable Worlds was a much-read general treatment of the subject. Another work, entitled Imaginary Worlds and Real Worlds, was a review of all previous writings on the habitability of worlds and the possibility of interplanetary communication.⁴⁵ In still another volume, Lands in the Sky, Flaminarion stated with conviction:

The Humanities of the heavens are no longer a myth. Already the telescope brings us in touch with their countries; already the spectroscope enables us to analyze the air they breathe… From the bottom of our abyss we can visualize these far-away nations, these unknown cities, these extraterrestrial people!⁷³³

The publication of Darwin's Origin of Species (1859) was soon followed by the development of an idea advanced by Swedish chemist Svante Arrhenius: Life may be ubiquitous thoughout the cosmos, carried from planet to planet by tiny space-spores (panspermia).¹⁹⁰⁶

The modern era of scientific xenology was ushered in with Henderson's important little book The Fitness of the Environment (1913), in which the Harvard biochemist attempted to demonstrate that both water and carbon are necessary in any living system on any planet in the universe.⁸⁷⁹ Superior astronomical data was becoming available, providing a still more accurate view of our solar system and galaxy.

The father of Russian astronautics, Konstantin E. Tsiolkovskii, wrote extensively on spaceflight and the possibility of ETs colonizing the Galaxy ahead of us. Alien civilizations, he pointed out, might well exist at many different levels of technological development.²⁰ In 1925, Tsiolkovskii summarized by noting the distinct probability that "perfection and dominance of the mind" have been spreading throughout the cosmos.⁷⁰²

Fictional treatments of extraterrestrial life proliferated. During the late 19th and 20th centuries the use of aliens became a vehicle for both romantic and far-flung scientific speculative statement.

Achille Eyraud's Voyage to Venus (1865) was the first fictional visit to that planet at a time when the idea of an inhabited Moon was virtually a dead letter.⁴⁵ In another trip to Venus, Garret Putnam Serviss's A Columbus of Space (1909), we find ape-like cave dwellers and beautiful telepathic humanoids.⁷⁴² John Munro painted a most delightful picture of life on Venus in A Trip to Venus (1897);¹⁸⁷² Edgar Rice Burroughs also took us to Venus and Mars, as did C. S. Lewis in his well-known trilogy.^364, 348 And Jupiter's steaming jungles, replete with dinosaurs and pterodactyls, appeared in John Jacob Astor's A Journey in Other Worlds (1894) — along with a brief excursion to Saturn.⁷⁴²

Voyages to other stars began to be written. With the French author Charles Ischir Defontenay we are transported to the star system of Psi Cassiopeia, in his 1854 novel of the same name, for a quick dose of haunting space opera.⁵⁶⁴ David Lindsay's A Voyage to Arcturus (1920) likewise is a romance, describing a visit to the extrasolar planet Tormance by spaceship and various adventures with the inhabitants there.¹⁸⁷²

But it was certainly "Mars Fever" that inaugurated the present epoch of science in science fiction. In 1877, under unusual conditions of good seeing, the Italian astronomer Giovanni Schiaparelli observed what appeared to be "channels" crisscrossing the Martian surface. Schiaparelli never maintained that his "channels" were relics of alien technology. Yet the word gained something in the translation into English: "Channels" became "canals," with the connotation of intelligent engineering efforts.

This was snapped up by Percival Lowell, an American astronomer who became so devoted to the search for life on Mars that he established an observatory in Flagstaff, Arizona for the sole purpose of studying the Red Planet.²⁰⁰⁹ His two books were widely read. Mars (1896) may have served as the scientific background for H. G. Wells' famous novel The War of the Worlds (1898) in which Earth suffers an invasion by Martians. Mars and its Canals (1911) might well have served in the same capacity for Burroughs when he wrote A Princess of Mars (1917),The Gods of Mars (1918), and classical sequels through 1940.

Mark Wicks' To Mars via the Moon (1911) is another enthusiastic depiction of Lowellian Mars: The telepathic Martians are found to have advanced canal-building technology and a Utopian socialist system of government. Lieutenant Gullivar Jones: His Vacation (1905) by Edwin Lester Arnold is a fantasy in which we meet carefree, friendly, gracious, but apparently purposeless Martians possessing an ideal political system. The Martians in Hugh MacCoil's Mr. Stranger's Sealed Packet (1889) have voice-recording devices and electric lighting but are otherwise technologically inferior to earthlings. And in Robert Croniie's A Plunge into Space (1890) we again find the frustrated hopes of finite humans projected onto more advanced aliens: Zero population growth has been achieved, workdays are only two hours in length, and the government is so perfect that there is no need for politicians!¹⁸⁷²

Two novels served as a bridge from romantic visits to alien planets in the 19th century to the modern era of science fiction. The first of these, Kurd Lasswitz's Concerning Two Planets (1897), is a fascinating tale of Martians who differ little from men physically but are comparatively advanced in ethics, social and physical sciences. Since they are more advanced, Lasswitz reasoned, they will be the first to visit us and not vice versa.¹⁰³⁸

The second important work is the aforementioned War of the Worlds by H. G. Wells.¹⁹⁵¹ The interaction of man and alien is explored realistically for the first time. Man must realize that he may someday face enemies with "minds that are to our minds as ours are to the beasts in the jungle."¹⁹⁵¹ We must also learn humility, we discover: In the end the invaders are destroyed, not by Earth's pitiful military might, but by the lowly bacteria of our planet against which the aliens have no immunological defenses.

After the early 1900s the number of scientific and fictional investigations of the problems and benefits presented by intelligent extraterrestrial races rises almost exponentially. In 1929 Hugo Gernsback coined the term "science fiction",¹⁸⁹⁶ and the cheap pulps of the 1920s gave way to the technological space opera of the 1930s and 1940s. Still more recently both science and science fiction have become remarkably sophisticated, dealing in detail with interstellar travel, extrasolar alien life, reasonable planetary environments conducive to the evolution of such life, and various particulars of possible alien physiology, sociology, and philosophy.

Xenology, the study of life on other worlds, is indeed "an idea whose time has come."