...and just who might be listening back?

 kw: book reviews, nonfiction, SETI, extraterrestrial life, philosophy

Seth Shostak is an idiot…or to be more charitable, he is dramatically misled by his own idealism. He is a very prominent proponent of sending messages toward possible alien intelligences, and he is the senior astronomer for the SETI Institute. He minimizes the possible risks we face from becoming known to "the Universe". If someone is out there listening, how will they react to learning that we exist?

In The Contact Paradox: Challenging Our Assumptions in the Search for Extraterrestrial Intelligence, author Keith Cooper lays it out plainly. He sums it up nicely in a paragraph on page 295:

We search the Universe for evidence of extraterrestrial life to make contact with others, for humanity to be able to share the Universe with others. Yet we find ourselves in a position of not being confident about whether we should try and make contact.

We dream of learning wonderful, life-changing things from superintelligent, hyper-advanced space aliens, or ET's (ExtraTerrestrials). All too often, the idealists in particular ignore the fact that every human being is both good and evil. Under some circumstances, we are altruistic, even heroic. Under others, every single one of us is capable of murder and larceny. There are no exceptions. Can we expect anything better of the denizens of another solar system? What are the chances of any intelligent species that arises due to evolutionary processes becoming unfailingly altruistic not only among themselves, but toward others to whom they are not remotely related?

The author makes a deeper point: by searching for "others" we search for ourselves. We project our hopes and dreams on them. It reminds me of a Chinese parable:

A man prayed daily for the Dragon to come. He dreamt about meeting the celestial being, imagining the wonderful things he might learn. One day there was a knock at the door; really, more of a crashing sound. The man opened the door and he saw him: scaly, fiery orange and red, forty feet long, with eyes the size of saucers and teeth like daggers. He screamed in fright, "Who are you?" The voice hissed and roared through him, "I am the Dragon. Am I not what you wanted?"

More succinctly: Be careful what you pray for; you just might get it.

A rather unbalanced segment of American society (few people elsewhere are as enamored of ET's as Americans) lives in combined fascination and fear of "flying saucers" and the "space aliens" that might "abduct" them to do "genetic experiments". Such sexual anxiety says a lot more about these people than it does about ET's. Is it really possible that Earthly genetics can have anything to do with ET's?

Sidebar: People with biological education (whether schooled or self-taught) usually know the Central Dogma of Genetics: DNA→RNA→Proteins. More recently, it has become clear that more than half of the DNA for which we know a function does not follow this dogma directly, but is regulatory, and modifies what happens when a "coding gene" is expressed to RNA and then to a protein. The key to how this works is the coding table, or The Code, which translates 64 codons into 20 amino acids plus a "stop" signal.

A little known fact about The Code: There is one Standard Code for the nuclear DNA of nearly all eukaryotic organisms, and it is also used for the DNA of most prokaryotic organisms (bacteria and archaea, which are bacteria-sized). But on Earth there are 25 other codes! See the details at this NCBI site. A few of these alternate codes are used by simple protozoan creatures, while many are for the mitochondria in various eukaryotes, and the rest are for various families of prokaryotes. This is just for Earth life. How many alternate codes are possible? Will any aliens out there have DNA like ours, and if so, will it be based on "our" Code?

The calculation P[64:20] yields 2.1x10³⁶ permutations. In common terms it is 2.1 trillion trillion trillion. That is one estimate of the number of possible DNA-to-Protein Codes. However, while there are as many as six codons per amino acid, the codons are grouped, so the number of efficient DNA codes may be smaller by a factor of a billion or so. Even then, we are left with a 28-digit number. It is extremely unlikely that an alien species from any other star system will have any genetic similarity to Earth life. Further, there is no guarantee that the same 20 amino acids will be used everywhere. It is actually more likely that, of the hundreds of possible amino acids, there would mostly be species with hardly any proteins that are "compatible" with any of ours. The aliens may not even be able to eat Earth foodstuffs (ourselves included!).

The book has an illuminating and comprehensive history of SETI and a detailed discussion of "things to look for" besides radio signals: flickering laser or maser light, "biosignatures" (such as the presence of both oxygen and methane together), and technosignatures other than radio (such as anomalies in a star's light caused by immense clusters of solar arrays). There is no need for me to get into detail; it's hard to beat the author's writing!

The book is a great joy to read. We have a lot to think about as we consider Who Is Out There.