Debating an excellent article with a friend tonight on The Fermi Paradox, which boils down to: If the Universe is full of a zillion stars capable of warming planets suitable for evolving intelligent life, why haven’t we heard from anybody?
I won’t re-iterate what Tim Urban said in his excellent article, because he’s articulated the issues there better than I ever could, but it set me thinking about the reasons cited for an apparent lack of galactic companionship. Where are our cosmic neighbours?
A few years ago I had an astronomy web site on the Interweb. Sadly, my grasp of numbers is akin to Enron’s accountants, and in any case, things have moved on in even the ten years its been since I last updated it. But I did visit one of the great mathematical frameworks which attempts to calculate approximate probabilities with regard to the number of intelligent civilizations likely to be extant in our Galaxy:
The Drake Equation
The best attempt at a systematic, scientific appraisal of the likelihood of intelligent civilizations capable of communicating in our galaxy is Drake’s Equation, N= R* fp ne fl fi fc L where
N = The number of communicative civilizations
R* = The rate of formation of suitable stars
fp = The fraction of those stars with planets
ne = The number of Earth-like planets per planetary system
fl = The fraction of those planets where life develops
fi = The fraction life sites where intelligence develops
fc = The fraction of planets where technology develops
L = The lifetime of communicating civilizations
Drake’s equation is not meant to provide a solution to the question, rather it provides a framework to drop new data into as our knowledge of each of the variables listed above grows.
An average ‘solution’ to Drake’s equation suggests that the possible number of stars in the Galaxy with Earth-like planets developing intelligent life is actually quite high (5 billion or 5%) and that there is a reasonable chance of these civilizations developing the will and technology to communicate (in other words, there are around a billion stars in our own galaxy with terran-like planets which might give rise to intelligent life.)
If it all sounds too good to be true, then it is! The last part of the equation, L is actually the biggest limiting factor. Civilizations, even long-lived ones, may only survive for a small fraction of the planet’s timescale. If a civilization lasts 10,000 years, it has only survived for 1 / 100,000,000 th of the planet’s life. Thus the chances of civilizations existing at the same time are reduced to 1 in a hundred million (1000 / 0.000001%).
Furthermore, the awesome distances between stars mean that by the time we received a message from even a relatively local star, say Deneb (1,600 light years away) either one of the civilizations might have perished before a reply could be received (3,200 years), so the practical search for life is limited to a small number of local systems. Even then, at the speed of light, communication would be slow. No extra-terrestrial signals have yet been detected.
So, disheartened by my new cosmic awareness of unimaginable distance, time, evolutionary mechanics, and sheer variety probably inherent in any intelligent life likely to develop, I gave up on the idea of us finding a needle in a 120,000 light year wide haystack that is our own galaxy (forget the other 170 billion galaxies observed in the Universe – the nearest is 2 million light years away and therefore texting to ask if we could borrow a cup of sugar is probably out of the question), and went back to watching Star Trek and listening to David Icke talking about how the Queen was a lizard.
But of course, the numbers are against the ‘unique humanity’ argument. Sky and Telescope ran a really cool feature on how many stars there are in the Universe recently, and the current estimate (quite easily worked out on a mobile phone or back of a fag packet) comes to, give or take a cosmos or two:
“…..measuring the number and luminosity of observable galaxies, astronomers put current estimates of the total stellar population at roughly 70 billion trillion (7 x 10 to the 22)….”
Or 70,000,000,000,000,000,000,000 stars in the Universe. And those are just the ones we know about (see Dyson Spheres and big fleecy star jackets below).
Which is an even larger number than my overdraft.
On reflection, I think the Fermi Paradox says more about us as a species than it does about the apparent absence of alien contact. We’re just not wired up to understand the horrific distances in anything other than number form. Nor imagine that there can be as many different kinds of alien life and civilisations as there are stars. Nor that the window of opportunity for any two civilisations is heart-rendingly narrow. The speed of light might seem fast, but between even our nearest neighbour, a teenyweeny red dwarf (Proxima Centauri, 4.2 light years distant, if we’re being formal) with no measured companions, it would take eight years to say:
“Hi, how are you?” …. 4 years static ….
“I’m fine, thanks.” ….. crap I should have attached a picture of my cat and other stuff
The universe obviously teems with life. It’s inevitable. What form that life takes and whether it would be capable of making contact, is the interesting question. Of course, our TV and radio signals, full of war, stupidity, cruelty, destruction and death, precede our messages of universal peace by some decades, so any ‘intelligent’ listener out there might well conclude that there is a chasm between our proclamations of civilisation and our actual behaviour, and give us a wide berth until we’ve grown up somewhat.
Interestingly, the formalised descriptions of possible civilizations are split into three types according to a schema called the Kardashev Scale: in simple terms a Type 1 civilisation can harness the total energy available on its own planet (I don’t think this means it’s great to exhaust irreplaceable fossil fuels in an orgiastic century of waste and environmental destruction); Type 2 civilisations get all Star Trek then, being capable of using all the energy produced by the star (which means not letting it out of the window, but constructing something exotic like a Dyson Sphere or a really big fleecy star jacket); Type 3 civilzations were obviously conceived when Nikolai Kardashev had consumed a monster doobie, because these civilisations are capable of harnessing the energy of a galaxy, which is even more gas than my old Austin Princess used. So more Forbidden Planet than Star Trek.
Again, I find it interesting that the explanations devised to explain why more advanced civilizations (which must surely exist in the cosmos) are either scientific (there are no observed signs of higher intelligence) or conceptual (there are advanced civilizations but there are various reasons they don’t apparently make contact with us), seem to say more about US than whatever civilizations out there might think.
My own offering is simpler: “HAVE YOU VISITED EARTH LATELY?” We took a paradise and we’re busy turning it into a filthy, overpopulated, killing field with acidified oceans and denuded forests, in like a century. So if we have cosmic neighbours, they’re probably using their advanced observation skills to conclude: “Man, those primitive chimps are utterly filthy. We’ll leave them flinging poo at each other for now.”
Alternatively, they may actually believe our Hollywood movies are documentaries and have therefore spent the last fifty years watching everybody from Leslie Nielsen to Tom Cruise generally resisting, blasting, hunting, zapping and totally nuking the fuck out of any alien race crazy enough to actually attempt a soft landing here.
Ultimately, though, I think there are other things we need to ask first, like: “Wouldn’t it be nice if we humans started being nice to each other before reaching out to the stars to try the same?”