The Search

Originally published in the Informanté newspaper on Thursday, 21 April, 2016.

The ancient Greek philosopher Aristotle famously said, “Man is by nature a social animal.” And since the earliest societies, we as a society have always been lonely, with us being the only intelligent beings we’ve encountered. Explorers scoured to the furthest reaches of human civilization to see who or what lies just beyond. And when we couldn’t explore, we imagined, and myths were born.

The Greeks had their gods live high up on a mountain, but all recognizably human with human motivation. The Roman and Norse gods, similarly, lived just out of reach of the human world, and even when we consider the Abrahamic god, we see recognizably human characteristics reflected in his visage. It appears that in our search, we unwittingly created our gods in our own image, in our search for others like ourselves. 

But as we slowly explored our own world, uncovering more and more, yet meeting no other comparable to ourselves, we started looking outwards. As astronomy opened up more of the galaxy to our inspection, we had new hope. But sight does not equal communication, and once again, we imagined. The literary genre on Science Fiction was born from this hope, with Jules Verne’s ‘From The Earth to the Moon’ an early example of mankind’s yearning to find others like ourselves.

By the early 20^th century, science had finally given us the means to speak over long distances, and almost immediately, we endeavoured to reach out to the universe around us. Nikola Tesla, Guglielmo Marconi, Lord Kelvin, and David Peck Todd believed that radio could be used to contact Martians, and the United States even had a "National Radio Silence Day" during a 36-hour period from August 21–23, with all radios quiet for five minutes on the hour, every hour, so that we could potentially pick up radio signals from Mars.

But science marches on. By the 1960’s, the Space Race was underway, and American and Russian Space probes had established as fact that in our solar system, Earth was the only planet that had produced intelligent life. We now had to cast our gaze even further, to the stars.

In 1961, Dr Frank Drake hosted a conference to start the first co-ordinated scientific search for extra-terrestrial intelligence. Attending were several prominent scientists, among them J. Peter Pearman, Frank Drake, Philip Morrison, businessman and radio amateur Dana Atchley, chemist Melvin Calvin, astronomer Su-Shu Huang, neuroscientist John C. Lilly, inventor Barney Oliver, astronomer Carl Sagan and radio-astronomer Otto Struve.

It was at this conference that Dr Drake unveiled the equation that would soon become the backbone of humanity’s search for an equal amongst the stars. Now known as the Drake equation, it is stated simply as follows: N = (R_*)x(f_p)x(n_e)x(f_l)x(f_i)x(f_c)x(L)

Some of these coefficients have over the years become much more clear as our understanding and exploration of the universe has progressed. NASA and the ESA has calculated the first of these, the rate of star creation in our galaxy, (R_*) as around 7 stars created per year. Recent analysis of Microlensing surveys has found that the fraction of those stars that have planets (f_p) may approach 1 – thus, that there are one or more bound planets per Milky Way star.

Based on Kepler space mission data, the estimate for the average number of planets per star having planets that might support life (n_e) as 0.4, with the nearest planet in the habitable zone as little as 12 light-years away. Unfortunately, after this term, the estimates start varying quite a lot, due to our incomplete understanding of the universe. 

The next coefficient, the fraction of the above that actually go on to develop life (f_l), is known to be above 0, since we exist, but unfortunately, the study of abiogenesis (how life arises from inorganic matter) is still in its infancy, but thus far shows that life originated on Earth from a single source. The current missions to Mars to find life there would be a tremendous help to this coefficient, as it would place it close to 1. 

This ties in closely with the fraction of the above that develops intelligent life (f_i), since on Earth we’ve only found one species (homo sapiens sapiens) that displays intelligence. Similarly, the fraction of the above revealing their existence via signal release into space (f_c) also provides some difficulty, since while humans have existed for over 100 000 years on Earth, we’ve only within the last 100 had the technological capability to send signals into space. 

The final coefficient, the lifetime of such a civilization wherein it communicates its signals into space (L), is of interest in general as well. Some scientists suggest that any species that reaches our level of technological achievement would be able to weather any threat to its survival, whereas others point out that our propensity for war and environmental damage could also be a hallmark of civilization, and that nuclear annihilation or environmental catastrophe would limit the survival of any intelligent civilization.

In the final analysis the answer to the Drake Equation, the number of planets with detectable signs of life (N), has varied wildly from 1 (we are alone in the galaxy) up to 36 million given the most optimistic values. Dr Drake himself estimated it could be as high as 10 000, while Carl Sagan hoped there were more than a million. But in 2010, the Italian astronomer Claudio Maccone published in the journal Acta Astronautica the Statistical Drake Equation (SDE). 

Maccone estimated with his SDE that our galaxy may harbour 4,590 extra-terrestrial civilizations, and that the average distance we should expect to find any alien intelligent life form may be 2,670 light-years from Earth. But even 500 light-years away, the chance of detecting any signal from an advanced civilization approaches zero. But that hasn’t stopped us.

Drake’s original group of scientists started a movement, and today the SETI Institute (Search for Extra Terrestrial Intelligence) coordinates the search worldwide, across nationalities and wherever a radio telescope has time available to search the skies. Even individuals across the globe can and are contributing, via the SETI@home program, whereby people download a computer client program that downloads and analyses SETI data collected around the globe whenever a home computer is idle, essentially donating computer power to this vast task.

Why do we do this? Of what use is it? Carl Sagan said, “For as long as there been humans we have searched for our place in the cosmos. Where are we? Who are we?” We hope that by searching for other life, we can determine our own place in the universe. Is there a general theory of living systems, a universal biology as there is a universal physics? Only by answering these questions, can we discover perhaps not only who we are, and where we are, but perhaps even why we are.