The cosmic probability of “practical isolation”

Sorry, fans of Asimov and Roddenberry — it’s time to forget all the Galactic Empire nonsense. Even if there were anybody else out there, it’s likely that we’d never know.

In “Alone in the Universe,” in the July-August issue of American Scientist, astrophysicist Howard A. Smith argues that not only is intelligent life vanishingly rare — if it’s out there at all — but even more remote is any chance of our making contact with another civilization.

Smith answers the cosmic “Are we alone?” question in a discouraging way: “Maybe not, but we might as well be.”

You’ll have to decide how relevant to this discussion is the fact — not mentioned in the American Scientist article — that Smith, of the Harvard-Smithsonian Center for Astrophysics and the former chair of the astronomy department at the National Air and Space Museum, in 2006 published Let There Be Light: Modern Cosmology and Kaballah: A New Conversation between Science and Religion.

In that book, Smith writes: “God’s book of Heaven is equal to a book of the Bible as a source of Truth and can be studied as such.” From the extended Google excerpt available free online, it appears that the whole book is full of lines like this.

OK, so the man has an agenda. For that matter, so do I. I suspect that you do, too. If his science is accurate, we can safely deal with his magical speculations separately.

Smith defines “intelligent life” as a species capable of interstellar communication, something we’ve been able to do for about a century.  And we have been able to search meaningfully for exoplanets for a time much shorter than that. Before now, everything about extra-terrestrial intelligence (ETI) was speculation. Now, Smith writes, we are in a better position to know:

The spin has been that because planets are common, alien civilizations must be abundant. But that doesn’t follow. The evidence so far does not alter the improbability that any ETI exists near enough to us to matter.

Smith essentially dismisses the Drake Equation — one way to estimate the number of worlds with intelligent life — as irrelevant to a short-lived species like us. If there are other intelligent species out there, if they’re not in our cosmic neighbourhood, what difference does it make to us that they exist? In other words, if we have to send a signal, wait thousands or millions of years for it to be received, then wait another equally long span of time for it to be answered, we’re not going to be the ones picking up the radiophone.

Smith advocates the “rare earth hypothesis,” which asserts that the number of planets capable of sustaining life like us is likely to be vanishingly small. He uses factors like planetary mass, orbital stability, the presence of liquid water, and other physical traits to suggest that we live on a remarkably fortunate world. It’s the “Goldilocks Effect” again.

And even if there are other planets with the perfect physical characteristics, how likely is it that they will replicate the geophysical and evolutionary accidents that led to us?

It’s true that Smith has an agenda, one we’ll look at more closely in a moment, but he is careful to stick to the science in his article. While others may generate different estimates of the likelihood of ETI, at least Smith’s arguments are based on extrapolations of physical measurements. Nowhere in the article does he cite scripture or God’s Will as proof of our uniqueness. Instead, he tries to use the science to demonstrate the uniqueness in which he clearly believes.

That makes Smith a scientist who’s a theist, not a theist who’s trying to pass as a scientist. And that makes him at least debatable, which six-day literalists never can be. The only overt passage that approaches “therefore, God” occurs early in the article:

It is therefore much more crucial for theology, philosophy, politics and popular opinion to ponder how humanity understands itself if we might be effectively alone in the universe — humanity being a species that is rare, precious, and neither irrelevant nor cosmologically insignificant.

In one sense, Smith is arguing that we can’t rely on either technological growth or benign contact to bring super-sophisticated beings to Earth to save us from our weaknesses and our excesses. So if you can’t call E. T., who you gonna call? For Smith, the answer is God, but he does quite a commendable job keeping his science separate from his superstition.

In the end, Smith takes a social and moral position with which I have little argument:

To recognize this conclusion [that we’re effectively alone] is to have a renewed appreciation for our good fortune, and to acknowledge that life on Earth is precious and deserves supreme respect. Even if we are not unique in the universe … though we may not know one way or the other for eons … we are fortunate. An awareness of our rare capabilities can spur deeper humility and an acknowledgement of a responsibility to act with compassion toward people and our fragile environment.

Again, it’s quite refreshing to encounter a believer who keeps his speculation separate from his science. If his take on the science leads to a stronger confirmation of his belief that we have a special place in the universe, good for him.

That’s so much better than letting one’s belief lead to a denial of the science altogether, isn’t it?