Posted on 02/24/2002 3:53:44 PM PST by LarryLied
Is there obvious proof that we could be alone in the Galaxy? Enrico Fermi thought so -- and he was a pretty smart guy. Might he have been right?It's been a hundred years since Fermi, an icon of physics, was born (and nearly a half-century since he died). He's best remembered for building a working atomic reactor in a squash court. But in 1950, Fermi made a seemingly innocuous lunchtime remark that has caught and held the attention of every SETI researcher since. (How many luncheon quips have you made with similar consequence?)
The remark came while Fermi was discussing with his mealtime mates the possibility that many sophisticated societies populate the Galaxy. They thought it reasonable to assume that we have a lot of cosmic company. But somewhere between one sentence and the next, Fermi's supple brain realized that if this was true, it implied something profound. If there are really a lot of alien societies, then some of them might have spread out.
Fermi realized that any civilization with a modest amount of rocket technology and an immodest amount of imperial incentive could rapidly colonize the entire Galaxy. Within ten million years, every star system could be brought under the wing of empire. Ten million years may sound long, but in fact it's quite short compared with the age of the Galaxy, which is roughly ten thousand million years.
Colonization of the Milky Way should be a quick exercise.
So what Fermi immediately realized was that the aliens have had more than enough time to pepper the Galaxy with their presence. But looking around, he didn't see any clear indication that they're out and about. This prompted Fermi to ask what was (to him) an obvious question: "where is everybody?"
This sounds a bit silly at first. The fact that aliens don't seem to be walking our planet apparently implies that there are no extraterrestrials anywhere among the vast tracts of the Galaxy. Many researchers consider this to be a radical conclusion to draw from such a simple observation. Surely there is a straightforward explanation for what has become known as the Fermi Paradox. There must be some way to account for our apparent loneliness in a galaxy that we assume is filled with other clever beings.
A lot of folks have given this thought. The first thing they note is that the Fermi Paradox is a remarkably strong argument. You can quibble about the speed of alien spacecraft, and whether they can move at 1 percent of the speed of light or 10 percent of the speed of light. It doesn't matter. You can argue about how long it would take for a new star colony to spawn colonies of its own. It still doesn't matter. Any halfway reasonable assumption about how fast colonization could take place still ends up with time scales that are profoundly shorter than the age of the Galaxy. It's like having a heated discussion about whether Spanish ships of the 16th century could heave along at two knots or twenty. Either way they could speedily colonize the Americas.
Consequently, scientists in and out of the SETI community have conjured up other arguments to deal with the conflict between the idea that aliens should be everywhere and our failure (so far) to find them. In the 1980s, dozens of papers were published to address the Fermi Paradox. They considered technical and sociological arguments for why the aliens weren't hanging out nearby. Some even insisted that there was no paradox at all: the reason we don't see evidence of extraterrestrials is because there aren't any.
Theoretical physicist Paul Davies claims that people are looking to extraterrestrials as "a conduit to the Ultimate." For many, the prospect of ETI has come to meet a need once met by religion. Even the SETI scientists say they are motivated by a nobler goal than the mere search for intelligence. Imagine, they say, the boost in knowledge, in morality, and maybe even in spirituality, to be gained from a billion-year-old civilization.Robert Jastrow imagines what it might do to our present religions. "When we make contact with them, it will be a transforming event," he says. "I do not know how the Judeo-Christian tradition will react to this development, because the concept that there exist beings superior to us in this universe, not only technically, but perhaps spiritually and morally, will take some rethinking, I think, of the classic doctrines of Western religion."
Any signals we detect, according to SETI astronomer Jill Tarter, will come from long-lived civilizations. This fact, combined with the fact that religions cause so many wars on this planet, means that our first detected signals will come from beings "who either never had, or have outgrown, organized religion," she said at a recent science/religion meeting sponsored by the Templeton Foundation and held in the Bahamas.
Other scientists and theologians at the Nassau meeting thought that pantheistic religions could survive an alien encounter, but most assumed that Western religion would certainly meet its fate when meeting extraterrestrials. Science historian Steven Dick called SETI "a religious quest" that might help to reconcile science and religion. But he assumed this would occur at the expense of Christianity, which could not accommodate the implications of ETI.
It strikes me that today’s scholars may be too quick to pronounce last rites over the faith that actually engendered most early ETI enthusiasts. Throughout the Middle Ages, well-read people believed that a "plurality of worlds" was impossible, following Aristotle’s arguments. In 1277, a council of bishops in France condemned this position, officially opening the way for many to take other worlds seriously.
Whether encouraged or discouraged by their churches, prominent Christians became the most prominent ETI promoters. These included Giordano Bruno and Nicholas of Cusa (fifteenth century), Johannes Kepler (sixteenth century), American Puritan divine Cotton Mather (seventeenth century), and Yale president/minister Timothy Dwight (eighteenth century).
Whether aliens will deliver a knockout blow to any particular religion depends, of course, upon exactly what aliens have to tell us about God. Materialists have traditionally assumed that Jews, Christians, and Muslims, believing in a transcendent God, will receive bad news. And the Christian belief in Jesus’ death for human sin seems particularly problematic to them. How could we reconcile Jesus’ death for all with the existence of other intelligent creatures in the universe?
Christian ETI enthusiasts, however, have a variety of responses to the skeptics:
- Jesus’ atoning sacrifice was a one-time event that covers aliens too. Oxford cosmologist E. A. Milne suggested that missionaries will eventually be preaching the good news to far-flung galaxies.
- Other civilizations may not have fallen into sin and so don’t require salvation. Oxford don C. S. Lewis wrote science fiction fantasies about such alien societies.
- God has become incarnate in the form of alien flesh in as many places where His creatures have fallen into sin. Scholars and rock singers have taken this position. And in the words of hymn writer Sydney Carter:
Who can tell what other cradle, High above the Milky Way, Still may rock the King of Heaven On another Christmas Day?
However, the Fermi Paradox and its descendants, e.g., Rare Earth--I find persuasive.
Therefore I am forced to conclude that we are alone--at least in this galaxy.
This is disturbing in many ways. For instance, if we are the best the Universe can come up with...it's a pretty sorry universe!
It gives everything a horrible portent. If you and I are members of the only intelligent species in the Universe, every time we go to the toilet takes on terrific import...
--Boris
All Marklar's Marklar are belong to Marklar.
On the other hand, if other civilizations were able to break the light barrier, then they would have been able to time travel also, meaning they would have been here already.
This also means that we never broke the light barrier or achieved time travel here on Earth with our own civilization. Not even millions or billions of years from now. Because if our civilization was able to time travel far off in the future, they would have already been here.
Alternatively, any civilization that reaches a suitable planet may discover that any life existing there is extremely toxic to their systems. Our best defense against a colonizing life form could be E. coli, for example.
Some observations:
Sagan was a Communist. Read "Intelligent Life in the Universe." Schlovskii and Sagan, 1964 (I am doing this from memory, so I may be imprecise) followed Soviet ideology.
Fermi was on the right track. The quote "Then where are they?" has been variously attrbiuted to 1939 and 1950. The Drake Equations point further along the way.
Robert Zubrin (in the 2002 April Analog) give one set of solutions to the equations. It is the wrong set.
The equations point to a range solution, not a single solution. My original calculations, using a log-normal distribution, suggested a maximum probability of one intelligent starfaring civilization in our near light sphere, (about 1 billion light-years in any direction) per billion years.
My newer upper range estimate would be about one civilization emerging per million years.
Sagan and Zubrin assumed (incorrectly) that the transistion from life t technological life is high probability. The Fermi paradox implictly states that it is not. Sagan-Zubrin focuses on possibilty. The Fermi paradox asuumes that we haven't observed alins because none are within observational range.
--K (Tommy Lee Jones), Men In Black
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