|Cover story -- The Universe|
Issue Date: October 20, 2006
Looking for company beyond the skies
Science's search is really for a wider, truer perspective on our own place in the universe
By RICH HEFFERN
The question of whether were alone in the universe or not is such a beguiling one that science now actively seeks an answer. Though out on sciences borderlands, this effort is a great human adventure, and the truth may soon be within reach. Italian monk Giordano Bruno was burned alive in the year 1600 for, among other things, proposing were not alone. A clear-cut answer would have a big impact on theology.
SETI, the acronym for the search for extraterrestrial intelligence, is sciences effort to detect evidence of intelligent life beyond the Earth by looking for signatures of its technology. The usual approach is to survey the sky with a radio telescope to detect electromagnetic transmissions from a distant world.
Catholics have been involved in the SETI effort from the beginning.
This quest is now 46 years old. Its a research field pursued by independent groups conducting projects in a few countries. About 30 scientists and engineers worldwide work in the field. The largest research group, roughly a dozen people, is at the SETI Institute in Mountain View, Calif., near San Jose.
Either there is other intelligent life out there, or we are alone in the universe. Either possibility is staggering, said Richard Barrans, astronomer at the University of Wyoming.
A SETI success, the detection of an unambiguous signal or message, would undoubtedly be one of the top news headlines in history, with undreamed of and far-ranging effects on religious views and theology.
Holy Cross Fr. Theodore Hesburgh, emeritus president of the University of Notre Dame, played an important role in emphasizing the compatibility of SETI and theologys search for understanding.
In fact, Hesburgh paid a visit to SETI pioneer Frank Drake in the 1960s and he continued to promote SETI by serving on the editorial board of Cosmic Search, a publication of one of the first search agencies. In the preface to an early NASA feasibility report, Hesburgh wrote: As a theologian, I would say that this proposed search is also one of knowing and understanding God through his works. Finding others than ourselves would mean knowing him better.
Staff at the Vatican Observatory Research Group at the University of Arizona in Tucson, a part of the Vatican Observatory headquartered at Castel Gandolfo in Italy, are involved indirectly. Its controversial among professional astronomers, Jesuit Fr. William Stoeger, staff member, told NCR. Many say its a long shot not worth taking; others say OK as long as we dont spend much money.
We participate here in panels on intelligent life in the universe, Stoeger said. Also two of us work in a project funded by the Templeton Foundation at the university known as Astrobiology and the Sacred, which includes discussion, lectures and producing educational materials involving astrobiology and its impact on religion and culture.
Certain assumptions underlie the SETI effort.
The most basic is whats called the principle of mediocrity, the idea that were not exotic or unusual in the universe but typically average when compared both with other locations and even other intelligences. Corollaries of this principle include the notion that communication would be mutually desirable and understandable.
If these assumptions are correct then contact of some kind seems inevitable given enough time, SETI scientists contend.
There are challenges involved since the direction, spectrum and method of possible communication, if any, are unknown. Our galaxy, the Milky Way, is 100,000 light years (the distance light travels in a year at the speed of 186,000 miles per second) in diameter and contains 200 or 300 billion stars. Its an ambitious task to survey this unimaginably vast area, and our galaxy is only one of another 300 billion or so.
As common as sand
In fact, sorting through billions on billions of stars is as formidable as looking for a needle among all the grains of sand on all the worlds beaches. Scientists estimate there are slightly more stars in the universe than there are sand grains on Earth. Yet the search can be narrowed by limiting it to stars that are like ours, which make up about 10 percent of the total -- and even to stars that have planets like ours.
In 1991 radio astronomers detected the first extra-solar planets. More evidence has been coming in. It was reported this month that the Hubble Space Telescope discovered a trove of candidate planets in a narrow region near the Milky Ways center, and astronomers say there must be billions more of them -- including many like Earth that orbit their suns in so-called habitable zones. SETI Institute scientist Seth Shostak told NCR: This discovery shows that planets are probably more common than cheap motels, that there are in fact more planets than stars.
To find a transmission from one of these planets, science must sort through most of the useful radio spectrum. Theres no way of knowing what frequencies might be used; broadcasts would be transmitted on a relatively narrow band as it would be too impractical to use a wide range.
SETI researchers usually target the water hole.
Thats a 300 megahertz (MHz) wide section of the radio spectrum, from 1420 to 1720 MHz. These boundaries correspond to radio frequencies emitted by hydrogen (H) atoms and hydroxyl (OH) molecules. Since H and OH combine to form water, the basis of life as we know it, this region of the spectrum may be favored by water-based life for interstellar communication.
Listening is the primary technique, though there are proposals for optical telescopes to look for detectable light signals. Youre not going to see them in person, I dont think, Shostak said. To go from here to the nearest star requires a 100,000-year trip. And thats longer than youre going to want to sit there eating airline food.
In 1960 Cornell University astronomer Frank Drake performed the first search, named Project Ozma after the Queen of Oz in L. Frank Baums childrens books.
A 75-foot-wide radiotelescope in West Virginia was used to monitor the stars Tau Ceti and Epsilon Eridani, at the 1420 frequency. Drakes search drew a blank but the effort was picked up by others and has never faltered since.
In 1963 Ohio State University inaugurated a search with the aid of funds from the National Science Foundation. This program achieved fame in 1977 when a project volunteer detected a strong signal received by the telescope that met the requirements for a possible intelligent source. He circled the telltale numbers on a printout and scribbled, Wow! in the margin. This signal, dubbed the Wow! Signal, is considered the most likely candidate discovered to date, but it has never been repeated and the source has never been confirmed.
In 1992 NASAs participation in SETI, the Microwave Observing Program (MOP), was canceled shortly after its start, ridiculed by grandstanding politicians. Democrat Sen. William Proxmire called it a futile project because there isnt a scintilla of evidence that intelligent life exists beyond our solar system. A scientist replied, As late as 1491 there wasnt a scintilla of evidence that America existed.
Private funding, in part by writer Arthur C. Clarke, Microsoft co-founder Paul Allen, Intel founder Gordon Moore, and Hewlett-Packard cofounders David Packard and William Hewlett has allowed the effort to continue as Project Phoenix, a systematic targeted search of nearby individual stars.
Another long-term project is SERENDIP operated by the University of California, Berkeley, at the Arecibo telescope in Puerto Rico. Another major project is conducted in Australia.
In a joint project with Berkeley scientists, the SETI Institute is building a dedicated array of telescopes that will equal a 100-meter radio telescope, the Allen Telescope Array. Activity on it will begin next spring. It is the forerunner of other larger radio astronomy arrays planned for later in the decade.
SETI is not only a long-term project but a grass-roots one as well.
Seti@home is a computing project launched in 1999 at Berkeley. Anyone can become involved by downloading then installing a software package, which then runs signal analysis on units of data recorded from radio telescopes. It actually runs on a home computer as a screensaver, doing its work during down time. The results are automatically returned to the university. Over 5 million computer users in more than 20 countries have signed up, contributing over 19 billion hours of processing time.
Early in the search, Frank Drake organized the first SETI conference and presented a key formulation in the endeavor, an elegant tool for quantifying our ignorance, what soon became known as the Drake Equation:
N = n* x fs x fp x ne x fi x fc x fl
This string of letter-symbols can be found on T-shirts and bumper stickers. It expresses the number N of observable civilizations that currently exist in our galaxy as a simple result of the multiplication of some more-or-less approachable unknowns.
The first term, n*, is the number of stars in the Milky Way galaxy, while fs is the fraction of sun-like stars, fp is the fraction of those stars with planets, ne is the average number of Earthlike planets that are potentially suitable for life in the typical solar system, fi is the fraction of those planets on which life actually forms, fc is the fraction of life-bearing planets where intelligence evolves, fl is the percentage of a lifetime of a planet that is marked by the presence of a communicative civilization.
Intelligent life may be rare
Take just one factor in the equation, fc. Many biologists point out that the evolution of self-aware life depends in a delicately balanced way both on aspects of the laws of physics and on Earths circumstances. For example, the fact we have a large moon circling us keeps the spin of the planet stable with respect to the sun, and a gas giant, Jupiter, further out from the sun sweeps the area, intercepting incoming comets and asteroids.
Finding evidence of primitive life on Mars would tell us that such life appears in many places, yet amoebas might not inevitably turn into opera singers. In fact, the lifeless surface of Mars today is a reminder that the building blocks may be there in abundance but things have to be just right for life to develop.
Its possible that life is common in the universe while intelligent life is extremely rare, Stoeger said. On the other hand, astrobiologists contend that evolutionary convergence makes intelligence likely, that once life is in place then it moves fairly quickly toward complexity.
While the SETI program continues looking for signals, many scientists feel the continued silence is discouraging.
Physicist Enrico Fermi in the 1950s suggested that if the universe was giving birth to many civilizations then given the its age of 15 billion years if they existed they would be here. If we think of our technological advances over the last 10,000 years and project those over millions of years, we can understand Fermis concern.
While some argue for UFOs and alien abductions to be evidence, the majority of the science community is unconvinced. The fact that as yet we havent seen or heard anything is significant, they say. If hi-tech societies or their thinking machines were out there, theyd have colonized the galaxy by now.
Others have countered what is known as the Fermi paradox with explanations that include variations on the TV show Star Treks idea of the prime directive: Aliens study life on Earth from a distance but wont interfere, ensuring we are unaware of their presence. Or the aliens havent noticed us; were in a backwater of the galaxy, Or because their technology is so advanced, we dont recognise signs that they have been around.
A consideration of one factor in the Drake Equation is particularly troubling: Perhaps its a common occurrence that intelligent civilizations arise yet inevitably reach a certain stage, equivalent to ours at present, wherein nuclear war starts or a religious cult releases a deadly virus setting that planet back to the level of primitive bacteria. Or, much as we like to pretend were independent of nature, if the ecosystem collapses, we couldnt survive, and this applies elsewhere. Its difficult to assess the likelihood of such scenarios, yet it seems we may be headed toward a harsh filter that screens budding intelligent life.
SETI has shown up in the evolution-creationism debate. Intelligent design proponents have said that if sciences criteria are tightened to disqualify intelligent design then it should apply to SETI as well. With SETI, what theyre looking for is in principle scientifically accessible, said Stoeger. Intelligent design proponents invoke something that is beyond natural processes; science cant do anything with that.
If one day -- maybe on a home computer -- evidence shows up, what would that mean for religion and Christian faith in particular?
Stoeger believes it would enrich Catholic theology immeasurably. Some might find it threatening, but I think it would make us realize that our theology can no longer be completely anthropocentric, or human-centered. If other entities are intelligent, then isnt it likely they too would in some sense be made in the image and likeness of God? Do they have moral sense? Are they in a state of primeval innocence as C.S. Lewis speculated? How has God revealed Gods self to them? What do they see as salvation? Whats their experience of religion? And, of course, did Jesus redeem them too? These are completely unanswerable questions until we see the evidence.
Our imagination is always going to be inadequate to divine reality. My own work in cosmology indicates there are possibly trillions of other universes besides ours. Were finding hard evidence that God is far above and beyond anything we can image, in ways that go beyond what people of earlier centuries ever imagined God to be.
John Haught, director of the Center for the Study of Science and Religion at Georgetown University in Washington told NCR: Contact with intelligent worlds would be one more in a series of occasions modern astronomy has provided for theology to deepen its sense of nature and God; it would also enlarge our appreciation of Gods love for diversity.
Jesuit Fr. George Coyne, former director of the Vatican Observatory, feels that such a discovery of intelligent life elsewhere, independent of the origins of life on earth, would be truly momentous. Two independent origins would mean life is prolific, he told NCR. That would bring about a dramatic change in our view of ourselves and of God.
Seth Shostak said detection of some evidence is likely sooner or later, especially with the advances in listening technology that are coming. Of course, deciphering an intercepted message from a civilization that is hundreds of thousands of years ahead of us might be problematic unless they are concerned with elementary education. Wed be somewhat like the pre-Columban Incas finding a barrel of books from Europe washed ashore. What would they make of them? It wouldve taken them centuries to decipher what theyd found, with no context for the information.
Another SETI pioneer, the late Carl Sagan, believed its possible that the future of human civilization depends on the receipt of interstellar messages.
Were a 100-year-old technology in a 10 billion-year-old galaxy, said Jill Tarter, director of research at the SETI Institute. Some benefits of contact might include finding out how to survive our own technology. Others might be able to define critical bottlenecks and elaborate various ways through them, or be able to tell us how to transition from our present-day my-God-versus-your-God conflicts to a more stable understanding of religion.
Sir Martin Rees, Englands astronomer royal, said: If SETI searches fail, that wouldnt render life a sideshow. Indeed, it would be a boost to our cosmic self-esteem: Terrestrial life, and its fate, would become a matter of cosmic significance.
Partly because of these implications for humanitys future, many scientists feel Drakes equation and the SETI effort stand as one of the most forward-looking of human endeavors. Sciences attempts to find company in the vast emptiness of the universe is really a search for a wider, truer perspective on our place in space and time and on the meaning of life, according to Alan McRobert, editor of Sky and Telescope magazine.
Just before he died, Carl Sagan described the universe he had discovered from a lifetimes work in astronomy: There is a place with four suns in the sky -- red, white, blue and yellow; two of them are so close together they touch, and star-stuff flows between them. I know of a world with a million moons. I know of a sun the size of Earth -- and made of diamond. The universe is vast and awesome, and for the first time we are becoming part of it.
Curiosity will keep the search going for years to come as a few scientists continue to look and listen for something like Princess Ozmas realm: a place unimaginably exotic, distant and difficult to reach. Perhaps the real quest though is to increase to a critical mass our awareness of how precious is our collective human life as we figure out how to survive our tumultuous adolescence.
Rich Heffern is NCRs assistant opinion editor. His e-mail address is email@example.com.
National Catholic Reporter, October 20, 2006
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