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Lonely Planets

Page 6

by David Grinspoon


  mumbo jumbo and devil worship, and less so for promoting the new

  astronomy. If they wanted to, New Age mystics or satanists could claim

  him as a martyr with at least as much veracity as scientists do today.

  Bruno was one of the first to advocate that each star is a sun with its

  own retinue of orbiting planets inhabited by intelligent creatures. Yet,

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  he based this conviction on metaphysical principles and mystical

  visions rather than observation or physical theory. Bruno couldn’t have

  cared less about evidence, measurement, or the intricacies of planetary

  motions. His adaptation of Copernicanism was a convenient co-opting

  of a recently published theory to support his belief in an infinite num-

  ber of inhabited worlds—a belief derived from a spiritualistic faith in

  the unity of the cosmos. If anything, Bruno did harm to the progress of

  science (and certainly to poor Galileo) by encouraging the Church

  authorities to associate Copernicanism with flagrant anti-Christian agi-

  tation. Surely some of the wrath that the Church vented on Galileo was

  really meant for Bruno, who refused to recant, reaffirming his beliefs

  and taunting his persecutors with his dying breaths as flames engulfed

  his body and freed his soul to travel among his infinite worlds.

  Personality and timing aside, Galileo’s biggest problem was simply

  that he had found the goods. The stark reality of his evidence suddenly

  made Copernican beliefs much more threatening. Before Galileo’s tele-

  scope opened a window to a new reality, cosmological questions were

  all hypothetical. Discussions of other worlds seemed as abstract and

  immune from verification as arguments about how many angels could

  dance on the head of a pin. Now, there were actual planets that you

  could see in the sky, and their existence implied that the Earth itself is in

  motion, contrary to the received truth found in Scripture. Telescopes

  and planets are mentioned in the Bible no more than particle accelera-

  tors and quarks, but with a little digging and creative interpretation,

  those who shrank with horror from the new, less human-centered uni-

  verse could find scriptural objections to back up their fears.

  The difficulty of the transition from biblically received knowledge

  to observational cosmology is well represented in a scene in Bertolt

  Brecht’s play Galileo. A group of learned astronomers have called upon

  Galileo to express their concern over his claims of finding new worlds.

  He invites his skeptical visitors to simply have a look through the tele-

  scope and see the new worlds for themselves. He is confident that, once

  they have seen with their own eyes, they will drop all objections.

  Fearing trickery or sorcery, they refuse to look.

  Forced to take a stand by Galileo’s observational successes and rhetor-

  ical excesses, the Church decided to put the kibosh on Copernicanism,

  but it was too late. Word was out. Telescopes are easy to manufacture.

  Soon observers all over Europe were marveling at the moons of Jupiter

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  and mapping the mountains of the Moon. Cusa and Copernicus had laid

  the dry timber and Galileo had provided the spark. A wildfire of ram-

  pant Copernicanism ripped through seventeenth-century Europe, and

  though the Church leaders spread fear to douse the flame, they could not

  stamp it out.

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  Every great scientific truth goes through three states:

  first, people say it conflicts with the Bible;

  next they say it has been discovered before;

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  lastly they say they always believed it.

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  —LOUIS AGASSIZ

  Where the telescope ends, the microscope begins.

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  Which of the two has the grander view?

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  —VICTOR HUGO, Les Misérables

  A F T E R T H E R E V O L U T I O N

  The Copernican revolution opened the floodgates, and the modern debate

  over life on other planets began in earnest. The original Copernican revo-

  lutionaries had approached ET life cautiously, but their followers went

  wild. Advocacy of the Copernican solar system became identified with a

  universe filled with planets and intelligent life, a “plurality of inhabited

  worlds.” Throughout the seventeenth, eighteenth, and nineteenth cen-

  turies, the phrase plurality of worlds was used to describe the idea of a densely inhabited cosmos, and “pluralists” believed in it.

  Many of Galileo’s followers and defenders confused the issues of

  Copernicanism and plurality. In the minds of the most ardent propo-

  nents of each, life on other worlds validated the Copernican system and

  vice versa. They would stand or fall together. The logic must have been

  irresistible: if Earth is just another planet, and other planets are like

  Earth (as far as could be told with seventeenth-century telescopes), then

  why shouldn’t the planets be Earth-like in every way, including inhabi-

  tants? This is called the argument by analogy, and it has reappeared

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  in various forms right up to the present as a rationale for belief in

  extraterrestrials.

  When we knew next to nothing about the other planets, the scant

  observations that did exist were interpreted as implying the existence of

  extraterrestrial life. The facility with which seventeenth-century natural

  philosophers put such a hopeful spin on their interpretations should

  serve as a cautionary tale to modern scientists itching to find evidence

  of alien life.

  Kepler’s belief in an advanced civilization on the Moon was based, at

  least in part, on careful observations. Recognizing the importance of

  air and water for life, he found evidence for both on our Moon. He

  thought that the dark areas were water and the bright areas dry land. In

  support of this he noted that the bright areas have rugged surfaces.

  Kepler decided that the Moon was not only habitable but densely

  inhabited. Because the lunar “spots” (he did not call them craters) are

  perfectly circular, he judged they must be cities: “When things are in

  order, if the cause of the orderliness cannot be deduced from the motion

  of the elements or from the composition of matter, it is quite probably a

  cause possessing a mind.”

  Kepler couldn’t imagine a natural process that created such perfectly

  circular forms, so he concluded that rational creatures were responsi-

  ble. Nearly four hundred years later, Arthur C. Clarke wrote 2001: A

  Space Odyssey, in which astronauts on the Moon dig up a monolith

  underneath the crater Tycho (named after Kepler’s despotic boss) and

  come to the same conclusion: this doesn’t look natural, so someone

  must have built it and put it there.

  Now we know that the lunar craters are not cities. We’ve been to the

  Moon. We understand how the energetic explosions caused by high-

  velocity cosmic collisions produce beautifully circular impact crater
s on

  all planets with solid surfaces.

  If we find ordered structures without a known “natural” cause, is this

  an indication of extraterrestrial intelligence? Kepler thought so, and

  modern theorists of SETI (the Search for ExtraTerrestrial Intelligence)

  agree.* Yet, as Kepler’s inference of lunar cities illustrates, failing to

  deduce the “cause of the orderliness” may be due to the ignorance of

  those attempting the deduction. Looking for surprising order in nature

  *Proponents of “intelligent design” creationism make a similar argument, replacing ET

  with God.

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  is not a bad approach for seeking extraterrestrial intelligence. But

  Kepler’s mistake should remind us to beware lest the limitations of our

  own intelligence cause us to find erroneous evidence of intelligence

  elsewhere.

  At the time of the Copernican revolution, the discovery of the “new

  world” by European explorers was recent history. This strengthened

  pluralist arguments by analogy. Vast realms of our own planet, previ-

  ously unknown to Europeans, were found to be densely inhabited by

  diverse creatures both familiar and exotic and, most importantly, by

  other humans.* In the wake of these findings, widespread life on the

  other “new worlds” of the post-Copernican solar system seemed just as

  likely.

  In addition to showing the planets to be worlds, the telescope also

  revealed a seeming infinity of unknown stars, which many observers

  believed to be suns. Teleological reasoning—the logic that things must

  be created for a purpose—was rampant in the seventeenth century. It

  was widely believed that the Earth, Sun, and Moon were created for

  our habitation, comfort, and pleasure. All of those innumerable suns

  must have been created for someone.

  C U R I O S I T Y A N D P O O R E Y E S I G H T : F O N T E N E L L E

  S P R E A D S T H E W O R D

  In 1686, Bernard le Bovier de Fontenelle, a poet, novelist, and natural

  philosopher who would later become secretary of the French Academy of

  Sciences, wrote Entretiens sur la Pluralité des Mondes or Conversations on the Plurality of Worlds. This book was an instant best-seller and international sensation. Excitement about pluralism was building, and

  Fontenelle both rode and helped to propagate that wave. Writing in a

  playful, whimsical style, he produced what has been described as the first

  popular-science book. To this day it is still a good read, and not just for a

  peek into the mind of a seventeenth-century pluralist and popularizer. It is

  a work of sweeping imagination written in provocative, witty prose with

  a bit of an edge. Fontenelle predicts spaceflight, discusses the habitability

  of other planets in our solar system and beyond, and offers vivid descrip-

  *Whether the disastrous consequences of this “discovery” for those human inhabitants augurs potential dangers of contact with extraterrestrials is a question I’ll return to in later chapters.

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  tions, centuries before the Apollo project, of the Earth as seen from space.

  He even urges his readers to consider what the inhabitants of Jupiter

  might think about Earth: “Even if they saw our Earth on Jupiter and

  knew about it there, still they wouldn’t have the faintest suspicion that it

  could be inhabited. If anyone were to think of it, heaven knows how all

  Jupiter would laugh at him. It’s possible we’re the cause of philosophers

  being prosecuted there who have tried to insist that we exist.”

  Conversations consists of a sequence of five dialogs, on five consecu-

  tive moonlit evenings, between a learned philosopher and an unedu-

  cated but sharp-minded marquise. The philosopher is convinced that

  the heavens are full of inhabited worlds. The marquise initially doubts

  this pluralist vision, and as she is gradually won over, Fontenelle

  skillfully defuses the doubts in the minds of his readers. By using a

  female character, Fontenelle implicitly advocates the notion that women

  can handle physics and philosophy—a radical notion in seventeenth-

  century France—while infusing Conversations with a delightful flirta-

  tious quality.

  Placing his wild conjectures in the voices of his characters, Fontenelle

  leaves the reader uncertain if the author himself actually believes what his

  philosopher argues. This frees him to offer dangerous speculations, as in

  his hints that the planets might be where they are just by chance instead

  of a creator’s design. Aware of the Church’s continuing objections to

  pluralist ideas, Fontenelle used a standard disclaimer, asserting that the

  aliens of his speculations were assuredly not men, did not descend from

  Adam, and were therefore irrelevant to biblical concerns. Nevertheless,

  Conversations was placed on the Catholic index of banned books one

  year after publication. But it was a hit with the public.

  Passionate about his beliefs but never dogmatic, Fontenelle pokes fun

  at everything, including himself and his profession: “All philosophy is

  based on two things only: curiosity and poor eyesight; if you had better

  eyesight, you could see perfectly well whether or not these stars are

  solar systems, and if you were less curious, you wouldn’t care about

  knowing, which amounts to the same thing. The trouble is, we want to

  know more than we can see.”

  It is remarkable how many modern scientific arguments about alien

  life were anticipated by Fontenelle. Sure, we have a lot more data now

  from astronomy, biology, paleontology, and geology. Yet, at its core,

  scientific belief in aliens rests on most of the same leaps of faith now as

  in the seventeenth century.

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  After convincing the marquise of the correctness of the Copernican

  system, the philosopher proposes that there is intelligent life on the

  Moon. He likens our view of the lunar surface to a Parisian in the tow-

  ers of Notre Dame gazing at Saint-Denis in the distance: “Everything

  one can see of Saint-Denis strongly resembles Paris; Saint-Denis has

  steeples, houses, walls, and it might resemble Paris in that it’s inhabited

  as well. All this will make no impression on my townsman; he will

  obstinately maintain forever that Saint-Denis is uninhabited because he

  has seen nobody there. Our Saint-Denis is the Moon, and each of us is

  a Parisian who has never gone outside his city.”

  “We’ll never know the people on the Moon,” the marquise declares,

  “and that’s heartbreaking.” The philosopher, unafraid to speculate

  about spaceflight, responds, “The art of flying has only just been born;

  it will be perfected, and someday we’ll go to the Moon. Do we presume

  to have discovered all things, or to have taken them to the point where

  we can add nothing? For goodness’ sake, let’s admit that there’ll still be

  something left for future centuries to do.”

  The witty marquise counters this by asking, if such spaceflight is pos-

  sible, why haven’t the people on the Moon already come to Earth? The

  philosopher responds, “The Eur
opeans weren’t in America until after

  six thousand years. It took that much time for them to perfect naviga-

  tion to the point where they could cross the ocean. Perhaps the people

  on the Moon already know how to make little trips through the air;

  right now they’re practicing. When they’re more experienced and skill-

  ful we’ll see them, with God knows what surprise.”

  This last exchange presages the modern scientific debate about

  extraterrestrial visitation. The marquise’s question has been rediscov-

  ered as Fermi’s Paradox: if spaceflight between inhabited worlds is pos-

  sible, surely we should have been visited by now. One popular modern

  answer to this is identical to the philosopher’s response: it takes a long

  time to develop spaceflight and travel between worlds. They’re just not

  here yet. Note that in Fontenelle’s day, six thousand years was consid-

  ered a good estimate for the age of the universe. The numbers have

  changed, but the arguments have not.*

  By the third evening, having convinced the marquise that the Moon

  is inhabited, the philosopher retreats to a careful agnosticism on the

  question: “You should never give more than half your mind to beliefs

  *I’ll come back to Fermi’s Paradox in a later chapter.

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  of this sort, and keep the other half free so that the contrary can be

  admitted if it’s necessary.” He then gives physical arguments, based on

  telescopic observations, suggesting the Moon may be uninhabitable.

  Noting that observers on the Moon could easily deduce the existence of

  water on the Earth by watching the motion of clouds, he points out

  that, by contrast, the features of the moon are fixed and motionless:

  “By this reasoning, the Sun doesn’t raise any vapors or mists above the

  Moon. So then she’s a body infinitely more solid and hard than our

  Earth, whose most volatile elements separate easily from the rest and

  rise up as soon as they’re stirred into motion by heat. The Moon must

  be some mass of rock and marble where there’s no evaporation, and

  furthermore, evaporation is so natural and so necessary where there are

  waters, that there can’t be any waters if none is taking place. Who then

  are the inhabitants of these rocks which can produce nothing, and of

  this land which hasn’t any water?”

 

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