August 21, 2006

Part XIV: Astrobiology

Uncovering Extraterrestrial Intelligence:
When Will It Happen, and What Will We Find?
Seth Shostak
SETI Institute, Mt. View, CA
24 min. (slideshow requires QCShow Player)
Audio only (mp3 format)
View as a webpage (quicktime, real player) (notes)

Any living being possesses an enormous amount of "intelligence," very much more than is necessary to build the most magnificent of cathedrals. Today, this "intelligence" is called "information," but it is still the same thing... This "intelligence" is the sine qua non of life. If absent, no living being is imaginable. Where does it come from? This is a problem which concerns both biologists and philosophers and, at present, science seems incapable of solving it.
— Pierre Grasse (1895 - 1985)

The Drake Equation, first expressed by Frank Drake in 1961, was intended to be used to predict the number of technological civilizations in the Milky Way, but it's proving to be more a Rorschach inkblot test for the people who use it.

Astronomers are in general more optimistic when completing the equation. Carl Sagan calculated that there may be millions of transmitting civilizations in our galaxy sending out detectable signals at the moment. In contrast, evolutionary biologists tend to be quite negative. Ernst Mayr famously calculated that in all of the galaxy, we are most likely alone simply due to the immense evolutionary improbabilities that we represent.

This negative view has become more popular in recent years with the rare Earth hypothesis, and we have some significant evidence in supporting this view. Enrico Fermi asked, when it was suggested to him that there should be thousands of technological civilizations nearby, "Where are they?" This is not an unimportant question. We have no evidence of their existence. In fact, our evidence lies quite to the contrary.

Geoff Marcy expressed the sentiment in an earlier lecture that he expects that bacterial life should be common in the universe, but he is otherwise quite pessimistic about the presence of technological, "intelligent" life anywhere near us. Every observation of the night sky for the past two hundred years has been one more negative confirmation its nearby presence.

Two questions haunt evolutionary biology: Is the evolutionary process inherently progressive? And if it is, is technological intelligence inevitable? Darwin and Sagan both believed that the answer to these questions was yes. The discovery of hundreds of similar civilizations to our own elsewhere in the universe would certainly remove any doubt.

Ultimately the only way to resolve the question posed by the Drake Equation is to simply go and look. In this lecture, Seth Shostak argues the surprising conclusion that if we were are going to find evidence of extraterrestrial civilizations, we're going to do it during our lifetimes. If we succeed at this task, it will be because of the advance of technology, Moore's Law in telescopic form.

It’s been four decades since the first modern SETI experiment, and researchers have still not recorded a confirmed peep from the cosmos. But new telescopes, improved backend hardware, and novel ways of looking for signals are all accelerating our scrutiny of the sky.

While the recently completed Project Phoenix carefully examined 750 nearby, Sun-like star systems over the course of 8 years, the Allen Telescope Array, now under construction, will be able to exceed this number of "targets" in its first year of full operation.

Thereafter, its reconnaissance of star systems can be expected to speed up in accordance with Moore’s Law, an empirically observed, exponential growth in the capabilities of digital electronics. Within two dozen years, the number of targets examined by the Allen Telescope Array will tally in the millions. The brute force march of technology is the most probable path in accelerating that first discovery. Indeed, the numbers suggest that such a discovery — if it occurs — will happen by 2030.

[It may be of interest to know that Frank Drake and Jill Tartar, who was the model for the character played by Jodie Foster in the movie, Contact, were sitting only a few feet from Seth when he gave this talk. The voice at the end of Seth's talk asking for questions is that of Jill Tartar's.]

— Wirt Atmar

About the Speaker

Seth Shostak is a Senior Astronomer at the SETI Institute in Mountain View, CA, and the 2004 winner of the Klumpke-Roberts Award awarded by the Astronomical Society of the Pacific in recognition of his outstanding contributions to the public understanding and appreciation of astronomy.

Before joining SETI, he used radio telescopes in the USA and the Netherlands, searching for clues to the ultimate fate of the universe by analyzing galaxy motion. While in the Netherlands, he also founded and ran a computer animation company.

Shostak is responsible for numerous outreach activities associated with the SETI Institute. He is science editor for The Explorer, (a monthly publication for supporters of the Institute), gives more than 50 talks annually for both academic and general audiences, and writes magazine articles (and books) about SETI. He also teaches informal education classes on astronomy and other topics in the San Francisco Bay Area.

He is the host for the SETI Institute's weekly radio program Are We Alone?. Each Sunday night, Shostak interviews guests who are on the leaading edge of science discovery and technological advance. The show gives callers the opportunity to ask questions of the world’s foremost experts in astrobiology and space exploration.

Subscribe to the Weekly Notice

If you wish to receive a weekly notice of the current lecture, please send a blank email to: