Alien Contact 1:  Is there anybody out there?

Since the discovery of the nature of planets and stars, there has been speculation about the possible existence of other intelligent races in space.  The belief that we are the only intelligent race in our galaxy is a modern day equivalent to the geocentric belief that earth was the center of the universe in the Middle Ages.  Modern efforts to find evidence of extraterrestrial high tech civilizations began around 1960.  A young astronomer, Frank Drake, presented what has been come to be known as the "Drake Equation".  This formula is a systematic attempt to estimate the probable number of high tech civilizations in our galaxy currently attempting to communicate with other stellar systems.  The equation contains a number of factors which are multiplied together to yield the estimate. 

The first factor in the equation has to do with the rate of formation of stars like our sun in our galaxy.  As a galaxy evolves, the first generation of stars fuse hydrogen up to iron.  Some of them explode and spew out a dust of elements.  The second generation of stars and their planets form from that dust.  There are about four hundred billion stars in our galaxy.  Stars vary in size, energy output and lifespan.  In order for a sun to support life-bearing planets, it must be medium sized and have a life span in the billions of years.  There is a classification system for stars which includes the designations O,B,A,F,G,K and M.  Our sun is designated a G type star and has been around for about 4 billion years.  It will be around for at least seven billion more.  F and K stars are similar to G stars.  Regardless of the rate of formation, about one fourth of the stars in our galaxy are F,G and K types which have existed for the required time.  This amounts to about one hundred billion.

The second factor deals with the probability of the formation of planets around F, G and K stars.  Early theories of planetary formation were cataclysmic.  They held that some sort of near collision of our sun with some other massive astronomical object tore out solar material that eventually coalesced into our family of planets.  Eventually, this was supplanted by the idea that the sun and the planets formed out of the same spinning cloud of dust.  Current belief is that it is common for small dense planets to form near the primary and gas giants to form further away.  If this theory is correct, then most of the F,G and K stars that we are considering should have families of planets with small dense planets near the star in the zone where life could evolve.

The third factor of the equation concerns the probability of the appearance of life on these planets.  Some theorists take the position that the origin of life on Earth was a highly improbable accident and may be unique in the galaxy.  However, recent theoretical developments are moving away from this extreme position.  Because of the peculiarities of the binding energies of certain atomic nuclei, the carbon, oxygen and nitrogen required for life will be plentiful in the interstellar dust.  Radio astronomy has detected characteristic signals sent out by organic molecules in these dust clouds.  Apparently, the processes which create these organic compounds are as ubiquitous as the necessary elements.  Recent theories of biogenesis propose that there may be self-organizing chemical processes involved with sedimentary clay in oceans that give rise to ever more complex structures which eventually become self-sustaining and self-reproducing.  This suggests that life will form often on planets with large quantities of liquid water.

The fourth factor in the equation brings us to the question of the evolution of intelligent life forms.  Some scientists argue that the appearance of intelligent life on earth was the result of a series of unique occurrences.  They claim that our specific combination of biology, form, environment and challenge could never be duplicated elsewhere.  More recent work argues just the opposite.  The same sort of self-organizing processes mentioned in the previous paragraph, which may have generated simple life forms, could also drive the complexification of living systems upward through multicellular development.  A challenging environment could lead to the development of complex nervous systems.  The concomitant development of language could lead to social development.  Against the argument that our form is a random accident, zoologists can point to the independent evolution of quadraploid forms with hands among whole different branch of evolution such as insects, reptiles and mammals.  Morphological studies suggest that the basic form of a human being is a reasonable design.  Two appendages for locomotion, two appendages for manipulation and a clustering of the sense organs at the top of the creature in close proximity to a large brain are a "good" design.

The fifth factor in the equation focuses on the appearance of technological civilizations with the ability and desire to communicate.  The same environmental challenges which would drive the appearance of social systems of complex humanoid life forms would also probably drive the externalization of sensation, locomotion, manipulation and intelligence which the human race has followed to a technological civilization.  The exploratory and communicative urges generated by such an evolutionary history would most likely lead to the drive to explore space and to communicate with other life forms on other planets.  Huge sources of energy and raw materials would have to be secured to provide the base for communication and possible exploration of their galactic neighborhood.  With the speed of light limit on exploration, it would be easier to send a message than to visit in person.

The final part of the equation considers the probable duration of a technological civilization.  Some sort of stable cultural plateau would have to be achieved which would permit long term investment in space exploration and construction.  Some will argue that our flirtation with the genocide of nuclear winter suggests that many civilizations would destroy themselves shortly after reaching the level which would permit exploration of space.  This argument rests on the assumption that the aggressive drive which fuels the exploratory urge would outstrip the communicative drive.  Recent geopolitical events suggest otherwise.  Other arguments claim that resources will quickly be depleted and a civilization will decline into barbarism from which it can never rise again.  A counter argument holds that the main resource is creativity and that any sophisticated space traveling civilization would be able to acquire nearly infinite resources to pursue its goals for great spans of time. 

Drake's equation stops there, but I think another factor must be considered.  Just because the ability and desire to communicate with other life forms exists at one point in the evolution of an enduring civilization, we cannot assume that communication attempts will be sustained over long periods of time.  When a species reaches the ability to manipulate the brain directly, intentional alterations of brain chemistry might rob them of the motivation to explore and communicate.  They might design such incredible simulated environments that they will turn away from physical exploration.  If such civilizations developed nanotechnology, they might create fantastic physical environments and differentiate into divergent "species".  Such a situation might be so involving that they would forget about space travel and interstellar communication. 

When all these parts of the equation are combined, the result is an estimate of the number of interstellar civilizations that exist right now in the galaxy who are actively trying to communicate with each other.  All we know for certain is that there are about 100 billion stars like ours in the galaxy and a high technological civilization desiring to communicate arose on our planet.   Depending what position is taken on the rest of the factors, the estimated number of other such contemporary occurrences varies from 1 to 100,000,000,000.  The specific results one arrives at are more a matter of faith than of science.  For the foreseeable future, this equation is more a guided tour of the types of questions that need to be considered than any sort of productive estimation process.

Since Marconi and Tesla in the last century, the human race has been using the radio frequencies of the electromagnetic spectrum to communicate.  Radio astronomy was born in 1933 with the discovery of radio frequency sources in space.  Around 1960, several different scientists identified the hydrogen emission wavelength of 21 cm as a likely place for interstellar communication signals to be found.  There are many sources of noise at lower frequencies and higher frequencies are absorbed by the earth's atmosphere.  Drake conducted Project Ozma, a 150 hour search of this wavelength, without significant result.  Interest in such searches grew and, in the mid 70's, NASA was on the verge of conducting a major search when the government withdrew funding for the project.  Individuals and institutions continued to develop the concept and do limited searches.  A new range of frequencies between the hydrogen emission at 21 cm and the hydroxyl (HO) emission at 18 cm was dubbed the "Water Hole."  (There is a nice metaphor here about the gathering of animals at a real water hole and the idea that galactic beings would gather at the EM water hole to communicate).  The government allocated funds for a new NASA search in 1982.  The Multichannel Spectrum Analyzer was developed.  It will scan millions of specific frequencies in the "Water Hole" per second.  The collected data will be sifted for about 40 possible types of signals.  The project will take ten years starting in 1992.  One group will do a complete scan of the heavens and a second will target 800 likely stars for a more concentrated survey.

A big problem we must confront is how to identify and decipher a message.  The conventional wisdom is that obviously artificial regularities in any signal from space would identify the presence of a message.  There is also an assumption that such a message would be composed of some sort of mathematical code which should be comprehensible to most high technology civilizations.  This may be true, but our own communications technology is exploring ever more efficient and complex compression technologies in order to put even more information into a message.  We might not recognize a highly efficient and sophisticated compression scheme.  On the other hand, it has already been suggested in science fiction novels that there may be several levels of message in such a signal.  The first level would be obvious, simple and short and would serve to attract attention.  The second level would be educational, more complex and longer.  This part would provide a key to decoding and understanding the third part which would be highly compressed, very lengthy and sophisticated.

There is an even more serious issue in our assumption that extraterrestrial communication would utilize electromagnetic waves.  What if advanced civilizations have gone beyond the EM spectrum? Today's physics abounds with theories about the structure and foundation of space-time which go far beyond the electromagnetic level.  If advanced civilizations can manipulate these fundamental levels of reality, they may be communicating with some method that is as far beyond our comprehension as electromagnetic communication would surpass the understanding of a caveman.  An analogy would be a primitive tribe looking out from a mountain to see if other tribes were using visible light to communicate.  They might see the lights of a city and not be able to detect any intelligible "message" in them while all the time the radio band around them is full of chatter.

Regardless of origin or content, if a decipherable message is ever received from a civilization on another planet, the realization that we are suddenly the "primitives' will have enormous consequences for our global society.