lunes, 20 de septiembre de 2010
SETI 2060, Do We Make Contact By Then?
This month the National Radio Astronomy Observatory’s Green Bank Science Center is celebrating the 50th anniversary of the modern day search for extraterrestrial intelligence (SETI).
In 1960 a young radio astronomer, Frank Drake, undertook a bold and visionary experiment: He used the 85-foot dish antenna at Green Bank, W.V. to listen for radio signals from extraterrestrial civilizations.
Drake recently retired from the SETI Institute in Palo Alto, Calif., without finding his aliens. He’s not alone. As early as the turn of the last century Nicola Tesla and the father of radio, Guglielmo Marconi, were independently listening for signals from Martians.
This half century of searching among the stars leaves me a little chagrinned because I’ve accused UFO believers of coming up equally empty-handed in over 60 years of chasing flying saucer “ghost stories.” After decades, both enterprises have absolutely zero, zilch, nothing of any consequence to convince us of life elsewhere in space.
Frankdrake_sm Even worse, the SETI effort has suffered collateral damage from the UFO silliness.
Still, it has persisted through lean times. SETI research has been largely living on private funding ever since NASA was forced to cut off money under Congressional mandate in the early 1990s.
I've accused the UFO folks of pursuing pseudo-science. But at some point I have to wonder if SETI is becoming a pseudo-religion. To be fair the program is absolutely scientific, but it has come up with nothing to date. So it is sustained purely by a belief that “they are out there, somewhere.” Or rather, more precisely, radio and optical searches test a neo-Copernican hypothesis that intelligent life is a condition of the universe.
So where will SETI be 50 years from now? What will popular articles be saying on the 100th anniversary of Drake's Project Ozma? Any prediction I make will almost certainly turn out dead wrong. But here’s some simple conjecture along with a few very extrapolations that can be made from our current state of understanding -- or should I say current state of ignorance.
The Astronomical World of 2060
1. The universality of life is established
* A series of ever larger space telescopes have assembled a catalog of dozens of inhabited planets lying within several hundred light-years of Earth. The closest worlds are imaged by an immense constellation of interlinked free-flying optical mirrors that form a “structureless space telescope.” Three-dimensional holographic projection posters in elementary school classrooms show these worlds rotating as virtual globes with clouds, seas and continents.
* Microbes are found on Mars, Europa and Enceladus. An exotic cryolife is uncovered on Titan. We realize that Genesis II has taken place. Specimens returned by astronauts and outer solar system robots are on Earth in class 5 biocontamination labs.
* Other scientists take a giant leap toward understanding life as a universal property of matter by successfully making a fully artificial life form in the lab. It reproduces, grows, and follows Darwinian evolution -- all without the benefit of genes refined over billions of years of evolution.
2. Extraterrestrial intelligent life manifests itself
Immense radio telescope arrays, many kilometers in area are robotically constructed on the radio-quiet lunar far side. They push deep into the Milky Way galaxy to sample billions of stars. The arrays also monitor the nearest inhabited exoplanets to eavesdrop on any telecommunications leaking into space.
With these exponentially growing capabilities, detection is made at last of an artificial radio beacon. It comes from the crowded core of our Milky Way, in the direction of the constellation Sagittarius. It is first overlooked as an oddball pulsar emission. Information content is minimal because this is just an acquisition beacon painting stars on a routine basis.
Overnight, humanity realizes that we are not alone in the universe. There is shock and awe -- and some skepticism by the world’s population. Cultural evolution is steered onto a different trajectory at this realization. This civilization game-changer overshadows sociology, religion, education and politics.
The public grows disinterested in the discovery when they learn that the beacon was broadcast thousands of years ago and apparently contains minimal information. (Depending on the state of science education in the United States by then, 10 to 20 percent of the population dismisses the signal as a government hoax.)
Major international powers engage in a radio telescope “Arms Race” to build the biggest possible facility for harvesting more transmissions. Soon, similar beacons from other comparably advanced civilizations are recognized as being artificial.
Finding and processing SETI transmissions becomes a bona fide science data collection program rather than exercise in hypothesis. Astronomers scramble to apply for research grants, and dream about receiving the Noble Prize.
Some signals are dug out of radio archival data. This kind of “hello we are here” message turn out to be surprisingly common along the galactic plane. Technological civilizations at a particular state of evolution apparently converge on similar beacon strategies that are energy-frugal and efficient.
In the absence of an exclusively directed transmission toward Earth, SETI astronomers diminish expectations of finding altruistic aliens wanting to share their advanced knowledge. Maybe the extraterrestrials are satisfied with simply broadcasting interstellar "tweets."
There is a lively debate among politicians and scientists as to whether we should respond to the signals. Who speaks for Earth? And what can we say to extraterrestrials?
A few long-lived alien civilizations patiently wait thousands of years for a return receipt on the transmissions before they devote more energy and to bandwidth into broadcasting an "interstellar Wikipedia" at targeted civilizations.
There is speculation that some beacons may simply be sentries that continue transmitting long after their builders have lost interest or died off as a civilization, as envisioned in James Gunn’s 1972 sci-fi story, “The Listeners.”
My modest scenario makes the assumption that radio will be the preferred medium for interstellar communication, though a similar strategy could play out at optical wavelengths using laser beacons.
By 2060 traditional SETI programs could be sidetracked or preempted if:
* An alien artifact is found in the solar system. It is simply leftover debris of a probe that visited over geologic time. The point of origin is a complete mystery. But isotopic analysis reveals the artifact was definitely built around another star. After intensive analysis the relic is put on public display. But it remains vastly more inscrutable that the Easter Island statures. Where are the builders? What was their purpose in visiting the solar system? Will they ever come back?
* Huge visible light or infrared telescopes stumble upon a strange phenomenon around a star. Scientists strictly apply Occam’s Razor to explain it. But the observation cannot easily be explained away as natural. The debate about artificial origin – such as a Dyson sphere structure -- remains unsettled by 2060.
* A powerful neutrino beam is detected. Astrophysicists conclude there is no known natural mechanism for making neutrinos in only this energy range, and so it must be artificially produced and aimed at us.
No SETI Success by 2060?
After a century of searching for radio or optical transmission perhaps nothing is found. SETI astronomers mull over the Drake Equation and conclude that a fundamental assumption about intelligence in space is missing. This gnaws at the brightest minds and theoreticians of 2060.
The Fermi Paradox is revisited. The conclusion is that biological intelligence -- with a curiosity to communicate -- is transitory at best. This does not rule our intelligent machines as successors to biological life. But these entities -- which roam the galaxy at will -- have no interest in talking to biological matter, any more than we tap out a coded message to pond scum.