SETI – Are We Alone?

November 9, 2007


Nobody talks about Fontenelle these days, but his Conversations on the Plurality of Worlds is a wonderful book. He was a vastly popular author, he lived for a century (1657-1757) and was a best seller for… centuries – how many authors can say that! His Conversations were written in 1686, and provide a popularized discussion of cosmic issues, e.g., man’s place in the universe; the Copernican System; the possibility of life on other planets. One of the arguments he advances through these dialogs is that there probably is life on other planets – it stands to reason with the universe being so large.

Almost as remarkable in this work as the assertion of the likelihood of extraterrestrial life is the fact that the dialog is between a learned gentleman and a woman, a woman who holds her own in the conversation! This was certainly not the usual style of such works, and they don’t even flirt (except, of course, at the most elevated intellectual level.) As for ET, it was simply one more piece of evidence for the essential unimportance of humanity and the earth from the cosmic point of view. We are just beings on a speck of dirt, probably one among millions of such agglomerations of life, so it is nonsense to think we are the center of the universe, ruled over by God or not. Fontenelle even deals with the problem of what we would now call existential angst:

“But,” she replied, “here’s a universe so large that I’m lost, I no longer know where I am, I’m nothing. What, is everything to be divided into vortices…Each star will be the center of a vortex, perhaps as large as ours.? All this immense space which holds our sun and our planets will be merely a small piece of the universe? As many spaces as there are fixed stars? This confounds me — troubles me — terrifies me.”

“And as for me,” I answered, “this puts me at my ease.”

Well, in his day, this assertion of the existence of ET was a radical thrust against the old way of thinking, with the God-Earth-Man at the center of everything, but today, it has become a notion that strikes me as faintly ridiculous and religious. We have the Search for Extraterrestrial Intelligence (SETI), a program of scientists that links together computers all over the world to search for patterns in the radiowave radiation that reaches the earth. Perhaps, in all of this, there is a detectable structure that would indicate that some intelligent life, somewhere, is producing the signals.

I beg to differ. The great biologist, Ernst Mayr, in his superb book What Evolution Is dispatches this point of view rather neatly.

  • The conditions for life to arise on a planet are rather special, and not met by most bodies in space.
  • Still, there are billions of stars, so it’s likely that some of them have planet systems that contain a planet or two with the right conditions, atmosphere, distance from the central star, etc. to support life.
  • So, we can conclude that it is quite probable that life does exist elsewhere in the universe, however, after the simplest life did appear on earth, there was nothing by prokaryotes for one billion years. “Highly intelligent life originated about 300,000 years ago, in only a single one of the more than 1 billion species that had arisen on Earth. These are indeed long odds.” [emphasis added]
  • Even if such life has arisen somewhere else in the universe, we must consider the chance that we will be able to communicate with it as virtually zero.

I might add that the chances of it being near enough to Earth to make it practical to communicate are also virtually zero. You can fantasize all you like about how these ET might have developed a way around space and time, but the chances are still virtually zero.