The blink of an eye

A while back I wrote about the rather terrifying idea of the "Great Filter" -- that life, especially sentient life, might be rare in the universe because there are hurdles of varying difficulties (those are the "filters") that have to be overcome in order to get there.  These include:

• abiotic synthesis of organic molecules
• assembly of those molecules into cells
• development of cells of sufficient complexity to segregate competing biochemical reactions (eukaryotic cells)
• multicellularity
• the evolution of intelligence
• the development of technology

The first two of these seem -- at least insofar as our models currently predict -- to be fairly straightforward, so most biologists expect that Earth-like planets in the habitable zone probably have lots of single-celled organisms.  The rest?  Uncertain.  After all, we have a sample size of one to analyze, so it's a little hard to make any inferences based on that.

All of this, of course, is by way of explaining the Fermi paradox -- that despite years of searching, we've found no good evidence of extraterrestrial civilizations.  But an even more alarming possibility is that the Great Filter lies ahead of us.  Perhaps all of those steps are surmountable, so stable rocky planets with atmospheres in their star's habitable zone ultimately do evolve intelligent life, but then it inevitably self-destructs.

I'm thinking about this today because yesterday I watched a short talk by the brilliant physicist Brian Cox about the topic, and while most of what he covered was information (and theorizing) I'd heard before, there was one piece of it that I honestly hadn't considered.  Suppose the Great Filter really does lie in the future, and technological civilizations always eventually come to naught.  Perhaps it's through nuclear annihilation, or biological warfare, or the catastrophic backfire of AI -- certainly at the moment, I don't think any well-informed person would argue that these are far-fetched possibilities -- but whatever the cause, intelligent species aren't intelligent enough to save themselves indefinitely, and their brief, fitful candle flames just as quickly wink out.

What that means is that at any given time, there might only be one or two civilizations in the entire galaxy, because their lifetimes are so short.  Cox describes visiting Frank Drake, the brilliant astronomer who gave his name to the Drake Equation.  Drake's hobby was raising orchids, and Cox said that on the day of his visit, he got to see one of the rare plants in Drake's greenhouse flowering.  Drake told him that this particular species only flowers once a year, and the flower is only open for a day or two; after that, the plant goes back into its previous quiescence.  Cox had simply lucked out and visited on the right day.

Could civilizations, Cox wonders, be like this orchid -- rising and falling so fast that you only have a moment's chance of seeing them before they collapse?

If this is true, then the galaxy's planets could be littered with the debris of dead civilizations.  Imagine it... planet after planet with archaeological sites as the only evidence that an intelligent species had once lived there.

It reminds me of the brilliant Star Trek: The Next Generation episode "The Chase," in which Captain Picard (himself an erstwhile archaeology student) is given a priceless, twelve-thousand-year-old ceramic piece made by the Kurlan sculptor called "the Master of Tarquin Hill" -- the product of an extinct culture now known only from the artifacts they left behind.

Of course, even artifacts don't last forever.  A few years ago, a couple of researchers considered the "Silurian Hypothesis" -- the idea that there may have been earlier, non-human civilizations right here on Earth.  (Named, I feel obliged to point out, after the reptilian Silurian race from Doctor Who.)  The question they asked was, if there had been such a civilization -- say, a hundred million years ago -- would there be any traces left?

And the answer they came up with was "No."  Likewise, the chances of any human-made artifacts from today lasting a hundred million years into the future is vanishingly small.  Consider that there's damn little left from humans who lived ten thousand years ago.  Nothing we make is likely to last a hundred million -- however rock-solid and permanent our creations may feel to us.

Understand that they're not saying there was such a civilization; only that if there had been, we'd probably have no way to know about it.  So even if there have been many intelligent species rising and falling throughout the galaxy, the marks they left on their planets would be nearly as ephemeral.

It's kind of a bleak prospect, isn't it?  All of our strutting and fretting is, for better or worse, over in the blink of an eye.  It reminds me of Percy Shelley's haunting poem "Ozymandias," which feels like a good way to conclude:

I met a traveller from an antique land,
Who said—"Two vast and trunkless legs of stone
Stand in the desert.  Near them, on the sand,
Half sunk a shattered visage lies, whose frown,
And wrinkled lip, and sneer of cold command,
Tell that its sculptor well those passions read
Which yet survive, stamped on these lifeless things,
The hand that mocked them, and the heart that fed;
And on the pedestal, these words appear:
'My name is Ozymandias, King of Kings;
Look on my Works, ye Mighty, and despair!'"
Nothing beside remains.  Round the decay
Of that colossal wreck, boundless and bare
The lone and level sands stretch far away.

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