Humans live and die by approximations. We are seldom as perfector as accurate as we would like to be. And as we contemplate what we might sayto an advanced extraterrestrial civilization, maybe that's a point we shouldemphasize.

If SETI succeeds, then it's very likely the civilization wediscover will be much older than our own. The reasoning is simple. The only waywe are likely to detect ET is if alien civilizations are much older than weare. If the typical civilization has the capacity to communicate by radio foronly a few decades before it self-destructs, then it's very unlikely that weand they will happen to co-exist in the long lifetime of our galaxy. Thatdisparity of age explains why current SETI programs merely listen for signalsfrom other civilizations, rather than transmit. Transmitting requires greaterpatience and more resources than listening, so shouldn't we expect ourcosmic elders to shoulder the burden?

Besides, what could a young civilization possibly have tooffer in an intellectual exchange across interstellar space? Surely advancedaliens would have little to gain from our understanding of astronomy orphysics, chemistry or mathematics. What then might we say to hold up our endof an interstellar conversation?

First Impressions

One of our natural tendencies, when we make contact withstrangers, is to try to impress them. Otherwise sloppy dressers might polishtheir shoes for a job interview, hopeful suitors will wash their cars for afirst date, and prospective children-in-law will be on their best behavior inthe presence of the parents of their intended. And sometimes such carefulself-presentation works — as my wife will readily attest.

Wouldn't we want to do the same in our first contact withET? Lewis Thomas, in his book Lives of a Cell, suggests that if we wantto impress an alien civilization, we should send "Bach, all of Bach,streamed out into space, over and over again." Thomas defends his choiceby noting that "it is surely excusable for us to put the best possibleface on at the beginning of such an acquaintance." And in fact when musicalselections were chosen for the interstellar recording borne by two of the Voyagerspacecraft, three of the 27 pieces were by Bach.

But perhaps even more impressive to an advanced civilizationwould be a more balanced presentation that reflects honestly on our foibles andshows a certain self-awareness of our imperfections. When looked at in thislight, perhaps even a description of our somewhat primitive science, mathematicsand technology could be illuminating to extraterrestrials.

For example, at a workshop on The Art and Science of InterstellarMessage Composition sponsored by the SETI Institute and the LeonardoNetwork, artist Richard Clar emphasized the ways that the process ofconstructing messages could be instructive to ET. According to Clar, we mightuse technologies developed for other purposes to compose interstellar messages.For instance, if we wish to tell ET about the three-dimensional structure ofthe human body, we might create messages using medical imaging technologieslike Computerized Axial Tomography — more commonly known as CAT-scans. Themessages would also, indirectly, contain information about the level of ourdevelopment as a species. Though our technologies may be crude byextraterrestrial standards, the rudimentary level of our accomplishments mayitself be of interest to an advanced civilization, which might long since haveforgotten the details of its own struggle to develop a stable, enduringsociety.

A Measured Response

Indeed, even a brief review of the history of terrestrialmathematics might prove of interest to an alien. As all high school geometrystudents can tell you, if we know the radius of a circle, we can easilycalculate its circumference. Presumably, extraterrestrials would also know thatc = 2pr, where "c" is the circumferenceof the circle and "r" is its radius.

What might surprise ET is how well humans get by, even whenwe are a bit inaccurate. Though we now know that the value of p is 3.14159 ? (and on it goes into infinity), earliermathematicians used much cruder estimates of p. For example, when wise King Solomon was planning a bathing area in thegreat temple he was constructing, its specifications indicated that the poolwould have a radius of 5 units and a circumference of 30 units. If you plugthese numbers into the equation for calculating the circumference of a circle,you'll see that the value of p was estimatedto be 3. While this number underestimates p byabout 5%, by all accounts, the temple turned out to be quite spectacular.Perhaps the most important message that ET could gain from this example is thatin spite of our imperfections and miscalculations, we humans are capable ofmoving forward, sometimes with a fair amount of style.

Embracing Imperfection

Indeed, rather than continually focusing on ways that we asa species are superior beings, perhaps as we attempt to make contact with ET,we should take the opposite approach. As a species we are, to put it bluntly,quite imperfect. More often than our egos would like to admit, we snap at ourspouses, forget appointments, pay our bills late and round off importantmathematical constants to the nearest integer.

Perhaps somewhere out there, circlinga distant star, is an extraterrestrial civilization a million years oursenior. Having long ago conquered war, poverty, and disease, having formed astable society capable of enduring on timescales that stagger our imaginations,what would they think of our human flaws and imperfections? If some day we sendthem a message of our own, signaling our interest in joining the Galactic Club,would our application simply be laughed off?

Who knows? They might be surprised, perhaps even pleasantlyso, to discover a young civilization that would initiate a conversation inwhich each exchange could take hundreds or thousands of years. Wise oldextraterrestrials might even admire our audacity for believing that, in spiteof our shortcomings, humans may continue to exist in the coming centuries — perhapseven long enough to receive a reply from ET.