March 23rd, 2009 10:30 EST
NASA and the Search for Extraterrestrial Intelligence (SETI)
SETI Astronomer: We Will Discover Intelligent Alien Beings By 2025
To: Robert Paul Reyes
To: President Obama, NASA and the American people
From: Bob Krekorian - Former NASA SETI Signal Detection Analyst
The NASA Astrobiology Conference in April, 2008 had as one of its topics, Future SETI: Technologies, Techniques and Strategies. Its premise was that after five decades of negative results from radio and optical SETI searches, there should be new approaches to the problem like detecting the biosignature of an extra solar planet. This premise regarding SETI is not supported by reality. In actual fact, very little systematic radio or optical SETI exploration has been performed.
The search for an extraterrestrial civilization is one of the most intellectually stimulating and potentially rewarding pursuits open to humanity. Many ideas have been put forward speculating on the existence of extraterrestrial civilizations, their number in the galaxy and their longevity. For those civilizations that become technological and do not self destruct, it is reasonable to assume that some number reach long lifetimes and are still scientifically curious. An interstellar beacon, which has as its sole purpose, communication with other contemporary technological civilizations in the galaxy is quite plausible under these circumstances.
What would be the motivation to construct such a beacon? Perhaps there is an altruistic code in the galaxy to preserve the history of all civilizations, past and present? Perhaps there would be interest in contacting new technological civilizations like us, knowing that there is a time window (hundreds of years) after the discovery of radio when some societies disintegrate because of sociological and environmental factors. In all likelihood, we would not be the first civilization that they have made contact with, thus finding one could be the gateway to many contacts. What could they expect to learn from finding one more? They may know a lot and have great understanding of science but the Earth`s civilization with its unique biology and history will be a new one for them to put into the larger context of life in the universe. Maybe they will ask for pictures and sounds from our culture? Maybe they will ask for detailed data on our solar system? This
seems far more practicable and feasible than sending out an armada of spaceships to explore other star systems. In a way, we would be their interstellar space probes.
When one considers all the concatenated probabilities connected with the formation of planet Earth, its composition, its stable environment over geological timescales that allowed complex life to flourish, the inescapable conclusion is that millions of sun-like stars will have to be examined to find one that is transmitting an artificial signal. That means the search volume of space could extend from one to two thousand light years. The NASA Kepler Mission which was just launched, will for the first time, give us hard empirical data on the number of Earth-like planets in habitable zones, their orbital stability in multiple star systems and the types of stars that have them. This will be crucial in defining the SETI search space.
If a targeted radio search is the SETI strategy of choice and detection sensitivity is essential, a search of millions of stars would take centuries to complete. And even if one of these stars is indeed broadcasting, detection could be missed because our detection sensitivity was just not good enough or interstellar scintillation degraded the signal during the observation time frame or the observation is not coincident with the duty cycle of the beacon or we are not sensitive to the particular type of signal structure being transmitted.
Based on the above considerations, it is logical (logic flows from causality) to expect that our galactic colleagues will make the detection problem for the contact as simple and straightforward as possible. Universality of the laws of physics and the logic of mathematics will govern their strategy to maximize the probability of detection.
I have come up with new thinking in how the interstellar communication link would be achieved. If my ideas are scientifically sound, it is quite possible to make a detection within a decade using existing telescopes and signal processing capabilities. The expectation is that the contact/acquisition signal will be an address (pointer), like in the C programming language. It will direct contactees to where the actual communication channel is located. The exact frequency channel of the beacon transmitter may be known, however our astronomical capabilities might be insufficient to receive the text of the extraterrestrial transmission.
The charter of NASA includes a statement, the expansion of human knowledge of phenomena in the atmosphere and space. Some of us who were with NASA for the Oct 12, 1992 (500th anniversary of Columbus discovering the Americas) SETI inauguration remember the worldwide interest and excitement created by what the agency was doing. Can we not rekindle this exploration spirit with a new generation of Americans?
NASA already has in place many of the resources needed to begin the search. The NASA SETI project was based on the 1977 NASA SP-419 report. See the conclusions from the report, Yahoo [NASA sp-419] which is still valid today. The 1993 congressional mandate to end United States funding for SETI is no longer in effect. Proposals for SETI grants are now being accepted by NASA and the NSF, but NASA is the proper federal agency to carry out a comprehensive search. The agency should form a small exploratory group, uninhibited by past orthodoxy and take a fresh look at the search for extraterrestrial intelligence.