Index
382,386,421 Abelson, Philip, 229 accidental contamination, 258 accretion, energy of, 157 Ackerman, Diane, 408 Aczel, Amir, 143, 147-148 adolescent optimism, 305 Africa, origin of life in, 126-127 Agassiz, Louis, 19 Age of Reason, 30, 33 Albee, Edward, 97 Aldrin, Buzz, 52 communicating with, 406-407 as a cultural phenomenon, xvii, 5 current knowledge about, xiii-xiv debunking, 351-352, 354 on Earth, 130 groups of believers in, 11 renewed hopes for finding, xiii, 64 stories about, 4-5, 337 Allen,...
Song Of Ourselves
Our efforts to anticipate and find life out there require us to start with some image of what that life should be like. Seventeenth-century writers imagined men and women in European dress occupying a universe of alternative Earths. Now the likenesses we paint out there take the form of squirming proteins swimming in Earth-like seas. On every evolutionary level, from the taproots to the tips of the tree of life, our thinking about alien biology is extrapolated from the local example. We assume...
Lowells Legacy
Lowell went to his grave in 1916 firmly convinced of the reality of his Martian civilization. Today, he is remembered as the man who, by force of personality, led the world on a wild-goose chase that ultimately proved to be one of the most embarrassing episodes in the history of science. It's unfortunate, because his Martian obsession is only a highly visible dark patch in a legacy with many bright spots. Lowell was a successful popularizer of astronomy who established an observatory of lasting...
Messag E In A Virus
One problem with radio or light rays is that they just flash through a system. The message does not stick around, so someone there has to be paying attention. If Earth had been bombarded with a continuous radio broadcast from a nearby star for 100 million years, ending in 1903, we would have completely missed it. What about a message that could be left on a planet to stick around until someone evolved with the ability to recognize and decode it It has even been proposed that the genomes of...
Immortal For A While
The idea of immortality, I've noticed, is troubling. People are quick to reject the notion. A group of academics at a philosophy of astrobiol-ogy discussion group at the University of Colorado once gave me a hard time about this. The topic was SETI. When I argued that we should consider a definition of intelligence qualitatively different from our own one that might indeed be immortal they practically shouted me *This could be the ultimate Microsoft marketing strategy down. They only wanted to...
Venus Interruptus
Modern planetary exploration rudely interrupted our age-old dreams of an Earth-like Venus. The high surface temperature on Venus was the first significant discovery ever made at another planet with a visiting spacecraft. Venus, a metal-melting furnace with a corrosive atmosphere and clouds so acidic they could etch glass, was declared off-limits to life. The romance was over. But (planets seem to be like this) every time we take a closer look, we see new sides to the place. Our understanding of...
Rare Earth
How unusual is the evolution of advanced life Two books published in the last few years show the full range of answers that we can logically reach Rare Earth by Peter Ward and Donald Brownlee, and Probability One by Amir Aczel. Each is written by credible scientists using rigorous arguments backed by mathematical equations. Yet, like the Epicureans and Aristotelians of ancient Greece, these thinkers reach opposite conclusions, as can be seen when we juxtapose the subtitles of the two works Why...
The Trials Of Galileo
So far our search for alien life isn't going too well. Although we cannot count Venus or Mars out yet, neither looks as promising at least for our kind of life as many believed when we began exploring. But from this we do not conclude that the universe is lifeless. We're not capable of reaching such a conclusion logically or emotionally. In this sense, aliens are like gods. No scientific result would convince us that alien life does not exist. Yet, the opposite proof positive of life on another...
Across The Great Divide
Almost as if we need to believe that we are not alone in the universe, or even somehow know we are not alone, this idea is resurrected in every era in new forms reflecting the attitudes and convictions of the day. Today, beliefs about extraterrestrials are polarized in a way that mirrors our culture's divergent attitudes about *Shades of the panspermia of Kelvin and Arrhenius. science. We scientists view the question as part of our turf, as the proper subject...
Microcosmic Gods
All living cells, from the bacteria lounging in your gut to the neurons humming in your brain, depend on an intricate pas de deux between nucleic acids and proteins. Neither can be made without the assistance of the other. The DNA code cannot be read without an elaborate protein transcription machine. The machine cannot be built without the code. Once it's up and running, this system works wonderfully. But it presents us with a serious chicken-and-egg problem. Which came first, proteins or DNA...
Wow False Alarms And Real Hope
As long as I've been aware of anything beyond the street where I lived, I've been aware of SETI. In the 1960s and early 1970s there were many small-scale, independent observing programs, mostly targeting nearby stars. Since no one had ever tried to look before, it seemed plausible that success could come quickly and easily. I first became conscious of SETI during this hopeful period, when the search was young and anything was possible. With my impressionable mind warped by science fiction and...
Curiosity And Poor Eyesight Fontenelle Spreads The Word
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 Pluralit 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...
Wolf Traps And Setbacks
In 1961, NASA awarded its first financial grant in the area of exobiology 4,485 to the Yale microbiologist Wolf Vishniac to develop a prototype device for detecting microorganisms on Mars. The practical task of designing and building instruments to find extraterrestrial life forced scientists to sharpen their ideas. Vishniac assumed that life always will be based on carbon, although he acknowledged, It may turn out that we are deluding ourselves that we are simply limited in our imagination...
Figuring The Odds
Frank Drake began the Green Bank meeting by writing an equation on the blackboard that summarized the major questions encountered when trying to estimate the number of intelligent civilizations in the galaxy. He intended only to suggest an agenda for the meeting, but his formula was destined to become the Drake Equation, the most famous equation in SETI research. Four decades later, it is still used in nearly every SETI paper, book, and discussion. The Drake Equation is not really supposed to...
Comparative Planetology 101 The Rules
Is our planet normal or some kind of freak of nature We desperately need context for the Earth story. The first thing to do is visit the neighbors and see what they're like. So what do we know about the lives of the planets What made them what they are today Were their fates preordained, bred in the bone Or was it experience and happenstance that gave each its own unique character Through comparative plane-tology we're seeking an understanding of the similarities and differences among worlds....
Out Of The Neutral Zone
We have been taught that science is largely value-free except for a sense of integrity to the truth. We are supposed to dispassionately interrogate nature and accept the answers, whether we like them or not. Yet, in the past, natural philosophers often mixed their spirituality, ethics, and values in with their science. Our neutral stance is not just a cop-out. It arises from an attempt to maintain a high standard of objectivity a commitment to letting nature be the judge. Undeniably, it is...
First Attempts
The modern era of SETI (the search for extraterrestrial intelligence) began in September 1959 when the Cornell University astrophysicists Guiseppe Cocconi and Philip Morrison published a seminal paper in Nature entitled Searching for Interstellar Communications. The idea of trying to communicate with beings on other worlds was not new. In the nineteenth century, several schemes were proposed for contacting inhabitants of the Moon or Mars by drawing huge diagrams on Earth's surface for the...
Come Together
However it happened, wherever it has happened, the birth of life is big news in Cosmic Evolution, right up there with the formation of quarks, atoms, molecules, stars, and planets. Smaller, previously assembled bits of the universe had repeatedly banded together to make big, new *On the other hand, maybe the first life-form was actually this undifferentiated ocean of organic replication, a global organism that lived before differentiating into cells. things. But something changed with life....
Soul Survivors
Today many of us invest hope in extraterrestrials who may come and save us from ourselves. The idea of contact with advanced ETs is as close to a scientifically palatable miracle as anything we can imagine. Might contact have a transformative effect on the human race, helping us enter a future in which we, too, become broadcasters and galactic travelers This question drives both SETI and ufology, each of which has at times been described as a new religion in the making. Perhaps our belief in...
Whats The Story
The word evolution in a scientific context usually conjures up the procession of life-forms parading across Earth's deep timescape. You know amoebas, algae, trilobites, apes, rock 'n' roll drummers, humans *A notable exception is Hindu cosmology, which describes a universe much older even than that described by Cosmic Evolution. and dolphins. But this chain of events on Earth is embedded within a much larger sequence of transformations that first prepared the ground and planted the seeds for...
Same As The Old Mars
There is a cyclical quality to our ideas about Mars. Like pilgrims seeking tears on a stone Virgin, we are ready to announce, at the least provocation, that we see water running there still. For over a hundred years now, the watery channels of Mars have reappeared in different forms. So, when MGS scientist Ken Edgett excitedly exclaimed at the press conference, This is not your mother's Mars I thought, No, but it might be my grandmother's. I am not convinced that the gullies are evidence for...
