The Fermi Paradox has always fascinated me, perhaps because SETI spokesperson, Carl Sagan was my astronomy professor at Cornell and—coincidentally—Sagan and Stephen Spielberg dedicated a SETI radio telescope at Oak Ridge Observatory around the time that I moved from Ithaca to New England. It’s a 5 minute drive from my new home. In effect, two public personalities followed me to Massachusetts.

What is SETI?

In November of 1984, SETI was chartered as a non-profit corporation with a single goal. In seeking to answer to the question “Are we alone?” it fuels the Drake equation by persuading radio telescopes to devote time to the search for extraterrestrial life and establishing an organized and systematic approach to partitioning, prioritizing, gathering and mining signal data.

Sagan explains the Drake Equation

Many of us associate astronomer Carl Sagan and Hollywood director, Stephen Spielberg, with SETI. They greased the path with high-profile PR that attracted interest, funding and radio-telescope partnerships. But, they were neither founders nor among the early staff. The founders, John Billingham and Barney Oliver assembled a powerhouse board of trustees, which included Frank Drake (Sagan’s boss at Cornell), Andrew Fraknol, Roger Heyns and William Welch. Among first hires were Jill Tarter, Charles Seeger, Ivan Linscott, Tom Pierson and Elyse Murray (now Elyse Pierson). Of course, Carl Sagan was advocated for the search for extraterrestrial intelligence, and he joined SETI as Trustee near the end of his life.

In The Birth of SETI, Tom Pierson reminisces about the early days of SETI. Also check out SETI pioneer, Jill Tarter, explaining how to write a message that will be understood by an alien civilization.

There is a lot of lore and love surrounding SETI, because its goal pulls directly on our need to understand our place in the cosmos. This week, SETI is going through a bit of transformation as it prepares for the next chapter in the search. So, where are the aliens? Are the funds and brainpower spent on peeping for aliens an investment in our own civilization, a form of entertainment, or a colossal waste?

This fascinating video offers 10 plausible solutions to Fermi Paradox. Fascinating, that is, if you can get past John Michael Godier’s dry, monotone narration. But. take my word for it. The concept and the content is exciting.

In a recent comment John Hunt mentioned the most probable solution to the Fermi Paradox and as more and more planets are discovered this solution becomes ever more troubling.

Whether civilizations are rare due to comet and asteroid impacts- as Ed Lu recently stated was a possibility- or they self-destruct due to technology, the greater danger is found in human complacency and greed. We have the ability right now, perhaps as hundreds or even thousands of other civilizations had, to defend ourselves from the external and internal threats to our survival. Somewhat like salmon swimming upstream, it may not be life itself that is rare- it may be intelligent life that survives for any length of time that is almost non-existent.

The answer is in space. The resources necessary to leave Earth and establish off world colonies are available- but there is no cheap. Space travel is inherently expensive. Yet we spend billions on geopolitical power games threatening other human beings with supersonic fighters and robot missile assassins. The technology to defend civilization as a whole from the plausible threat represented by this “Great Silence” will cost us no more than what we spend on expensive projects like vertical take-off stealth fighters and hyper-velocity naval rail guns. But it is not the easy money of weapons; it is the hard money of vehicles and systems that must work far from Earth that is unattractive to the corporate profit motive.

Atomic spaceships capable of transporting colonists and intercepting impact threats are the prerequisites to safeguarding our species.

If intelligent, technological extraterrestrial life exists in the galaxy, then it is conceivable that such a civilization might embark on a similar exploration strategy. Extraterrestrial intelligent (ETI) civilizations may choose to pursue astronomy and search for planets orbiting other star systems and may also choose to follow-up on some of these targets by deploying their own remote exploratory spacecraft. If nearby ETI have observed the Solar System and decided to pursue further exploration, then evidence of ETI technology may be present in the form of such exploratory probes. We refer to this ETI technology as “non-terrestrial artifacts”, in part to distinguish these plausible exploratory spacecraft from the flying saucers of science fiction.

In a recent paper titled “On the likelihood of non-terrestrial artifacts in the Solar System”, published in the journal Acta Astronautica (and available on arXiv.org as a preprint), Jacob Haqq-Misra and Ravi Kopparapu discuss the likelihood that human exploration of the Solar System would have uncovered any non-terrestrial artifacts. Exploratory probes destined for another star system are likely to be relatively small (less than ten meters in diameter), so any non-terrestrial artifacts present in the Solar System have probably remained undetected. The surface and atmosphere of Earth are probably the most comprehensively searched volumes in the Solar System and can probably be considered absent of non-terrestrial artifacts. Likewise, the surface of the moon and portions of Mars have been searched at a sufficient resolution to have uncovered any non-terrestrial artifacts that could have been present. However, the deep oceans of Earth and the subsurface of the Moon are largely unexplored territory, while regions such as the asteroid belt, the Kuiper belt, and stable orbits around other Solar System planets could also contain non-terrestrial artifacts that have so far escaped human observation. Because of this plenitude of nearby unexplored territory, it would be premature to conclude that the Solar System is absent of non-terrestrial artifacts.

Although the chances of finding non-terrestrial artifacts might be low, the discovery of ETI technology, even if broken and non-functioning, would provide evidence that ETI exist elsewhere in the galaxy and have a profound impact on humankind. This is not to suggest that the search for non-terrestrial technology should be given priority over other astronomical missions; however, as human exploration into the Solar System continues, we may as well keep our eyes open for ETI technology, just in case.

This is my video presentation on YouTube:
Risks of SETI, for Humanity+ 2010 summit

Background: The Fermi Paradox
According to a simple but powerful inference introduced by physicist Enrico Fermi in 1950, we should expect to observe numerous extraterrestrial civilizations throughout our galaxy. Given the old age of our galaxy, Fermi postulated that if the evolution of life and subsequent development of intelligence is common, then extraterrestrial intelligence (ETI) could have colonized the Milky Way several times over by now. Thus, the paradox is: if ETI should be so widespread, where are they? Many solutions have been proposed to account for our absence of ETI observation. Perhaps the occurrence of life or intelligence is rare in the galaxy. Perhaps ETI inevitably destroy themselves soon after developing advanced technology. Perhaps ETI are keeping Earth as a zoo!

The ‘Sustainability Solution’
The Haqq-Misra & Baum paper presents a definitive statement on a plausible but often overlooked solution to the Fermi paradox, which the authors name the “Sustainability Solution”. The Sustainability Solution states: the absence of ETI observation can be explained by the possibility that exponential or other faster-growth is not a sustainable development pattern for intelligent civilizations. Exponential growth is implicit in Fermi’s claim that ETI could quickly expand through the galaxy, an assumption based on observations of human expansion on Earth. However, as we are now learning all too well, our exponential expansion frequently proves unsustainable as we reach the limits of available resources. Likewise, because all civilizations throughout the universe may have limited resources, it is possible that all civilizations face similar issues of sustainability. In other words, unsustainably growing civilizations may inevitably collapse. This possibility is the essence of the Sustainability Solution.

Implications for the Search for Extraterrestrial Intelligence (SETI)
If the Sustainability Solution is true, then we may never observe a galactic-scale ETI civilization, for such an empire would have grown and collapsed too quickly for us to notice. SETI efforts should therefore focus on ETI that grow within the limits of their carrying capacity and thereby avoid collapse. These slower-growth ETI may possess the technological capacity for both radio broadcasts and remote interstellar exploration. Thus, SETI may be more successful if it is expanded to include a search of our Solar System for small, unmanned ETI satellites.

Implications for Human Civilization Management
Does the Sustainability Solution mean that humanity must live sustainably in order to avoid collapse? Not necessarily. Humanity could collapse even if it lives sustainably—for example, if it collides with a large asteroid. Alternatively, humanity may be able to grow rapidly for much longer—for example, until we have colonized the entire Solar System. Finally, the Sustainability Solution is only one of several possible solutions to the Fermi paradox, so it is not necessarily the case that all civilizations must grow sustainably or else face collapse. However, the possibility of the Sustainability Solution makes it more likely that humanity must live more sustainably if it is to avoid collapse.