Is it easier to believe we’re exceptional and the universe was made for us, or that the universe is full of beings like us? Who cares? The universe is telling us that neither is true.
The Drake Equation: we are not alone
You might not remember it by the name, but you’ve probably heard mention of it at some point. The Drake Equation claimed to at least approximate the potential for intelligent life in our galaxy. It was presented by Frank Drake in 1961 at the launch of the SETI project. The figure he came up with for civilisations out there was between one thousand and one million.
Obviously, that kind of range is almost meaningless beyond this: there should be some civilisation out there. Which is, of course, a handy conclusion to draw when you’re arguing for government to give you millions of dollars to beam messages into space.
Consider our popular science fiction. Star Trek, Star Wars, Doctor Who and many more besides, posit an extensive variety of species out there with technology and their funny little ways. So, for the sake of this discussion, let’s be content to run with the lower threshold of one thousand civilisations in our galaxy. Just one thousand. One thousand civilisations is worth our attention, isn’t it?
We have assumed that in a galaxy as big as ours life has popped up all over the place. Indeed, our understanding of chemistry and how it can become biology (whilst we haven’t quite nailed the cause and effect, we have a good understanding of the predicates) does suggest this is likely to be the case. There ought to be life all over the place. But life is not civilisation. For life to become civilisation requires time. Time for evolution.
Drake’s Equation started from a set of assumptions that broadly boiled down to this: there’s nothing special about the Earth, you’ll find planets like it circling other stars, and where such conditions appear, there is an inevitability to the chemistry and then the biology.
There’s an assumption lurking here which is a reaction to the abiding model of the universe that had prevailed for millennia. In various modes, be we talking Horus, Odin, Kali or Jesus, the abiding narrative stated we were special, the centre of the universe, made by god(s). Drake’s model, however, assumes the contrary – life happens, all the time. If it happened here there’ll be loads of other places it happens. We’re nothing special.
Fair enough, eh?
The universe isn’t interested in your psychodrama
Well, as it turns out, no. It turns out that the Earth is an oddball amongst worlds, but we’ve only known this since we’ve been able to see how other solar systems are constituted, and that’s only the last 20 years or so.
Exo-planets are those planets circling stars other than our own, or sometimes just freewheeling through the void, cut loose from their star. There is a variety to them, but there are patterns, types of solar system, with features that seem to repeat often, features that are expressions of physics doing its funky thang. There are universal laws that result in the same things happening again and again.
That said, there can be odd things that cut across the likely and predictable, little variations that, over time, have profound effects and result in extreme variations from the norm. That’s the nature of probability, over a lot of space and a lot of time: there will be some freaky exceptions. I mean, the odds are, if you play the lottery, that you won’t win. Or maybe you win a couple of quid now and then, but that won’t even cover what you spend on tickets. That’s normal.
Nevertheless, someone wins millions on the lottery.
Our solar system features some smaller rocky planets closer to the sun, with gas and ice giants further out. There’s ‘the goldilocks zone’, not too hot, not too cold, where one of the rocky planets may retain water and gaseous atmosphere and so permit the necessary chemistry to spark life. Is this a typical constitution of a solar system?
And the answer is: nope, not even close. Our solar system is not the model for the rest of creation, indeed, it’s a weirdo. Repeatedly, we find that other solar systems have many similarities with each other, but that ours diverges from these standards in key regards.
It is what it is
First issue: that smaller rocky planets closer to the sun, gas and ice giants further out thing: it isn’t how our celestial neighbours do it. Indeed, we now believe it’s not how our own system did it, not originally. It seems that when a system forms around a nascent star, the gas giants are formed closer in, and, indeed, we now believe that was originally true of our system. However, in the early epochs of a system’s life, conditions seem to be horribly volatile. Gravities interact, push and pull, and worlds collide. Our moon may be the consequence of such a collision, so might the asteroid belt. At some point, after some complex interaction of gravities and, perhaps, collisions, our gas giants were flung further out, leaving the inner system to the rocks.
It isn’t just the relative position of the planets though. Our earth is atypical in itself. The Earth and Venus are very similar in size, Mars a little smaller. For some, decades ago, this suggested an optimal size for rocky planets that would be about the size of Earth, give or take a bit. We have found worlds broadly like this, but many of the rocky worlds we see around other stars are about twice the size of Earth and Venus, or even bigger. We see this repeatedly, indeed, the ‘Super-Earth’ class of exoplanet is an extremely common type, but it is entirely absent from our own system. There are inevitable implications to such worlds regarding gravity and then the impact upon atmosphere. Such implications do not rule out the possibility of some kind of life on a ‘Super-Earth’, but it would be very different to life on Earth.
Therefore a number of the key assumptions upon which the Drake Equation is based are now known to be simply flat wrong.
Life and time
There’s another problem: think about the nature of life on earth. The earth is about four and a half billion years old. Life is thought to have been here for a little under four billion years, but spent nearly three billion years being microbes. The first vertebrates were fish, and they only show up half a billion years ago. Some 200 million years after that, some of them flail onto the shore.
At the point some mutant fish is flopping upon a shore for the first time, we are still three hundred million years from dinosaurs roaming the Earth.
But, after hundreds of millions of years, the dinosaurs do come along and the dinosaurs dominate planet earth for about 150 million years. They’re incredibly successful. They’re happily lumbering around for epochs. To give you a sense of timescale, you might recall those old Ray Harryhausen movies like The Land that Time Forgot with the stop motion dinosaur battles. An earlier one, called Evolution, set T-Rex and stegosaurus in primal conflict. Disney’s Fantasia also features a sequence of Stegosaurus and T-Rex facing off. However, in reality, this never happened. Stegosaurus died out a hundred million years before T-Rex evolved. Indeed, T-Rex is closer in time to us now than Stegosaurus was to T-Rex.
There was no reason for dinosaurs to not keep going strong. None. They could be here now, roaming the continents. The mammals would never have had their chance to evolve beyond the status of dinosaur snack were it not for one thing, and that one thing was the universe throwing a huge great rock at the earth, a rock that wouldn’t have needed to be much bigger to just end all life altogether.
That rock all but destroyed the dinosaurs (some actually did survive, and are in fact here with us now. You call them ‘birds’). That permitted a new world order to emerge, but it took 65 million years to get from dinosaur snack to you and the iPhone.
That’s a lot of time. Lucky there wasn’t another big rock, eh? Bruce Willis was nowhere to be seen for ages.
You may not grasp how lucky.
Back to the gas giants being further out than is normal.
Big rocks and their war against iPhones
Space is big. Our solar system is not as volatile as once it was, but it isn’t serene either. There’s various objects out there apart from the eight planets. Asteroids and comets cut across their orbits all time. However, the system is big, so collisions are rare.
Thing is, we should be seeing more collisions, they should be more frequent. Indeed, by our standard frequency thus far, we’re overdue one (not necessarily dino-killer size, but dangerously big). Remarkably few rocks get into the inner system where we are, and this is because the gas giants suck them up, or their gravity deflects them.
But remember, most of those other solar systems we’ve observed across the galaxy have their gas giants closer in, so they’re not deflecting those rocks. Many more of those rocks are hitting the planets with the potential chemistry for life. So, life in the simple sense of microbes might be springing up all over the place, but must expect a bloody great rock to spoil the party every few hundred million years.
And it takes billions of years for microbes to get to fish, let alone dinosaurs, and dinosaurs didn’t build an iPhone.
That is what MOST systems we’ve observed look like. They may have life, but are not likely to get the chance to evolve as far as the dinosaurs, let alone get an exquisitely timed, opportune rock at just the moment mammal-like creatures emerge, ready to take over the planet and reboot the evolutionary race.
The Drake Equation is a nonsense. The particular exceptions and deviations from the norm we observe through the galaxy that characterise our own system, with crises spurring revolutions so nicely timed, are disappearingly unlikely to be replicated elsewhere. I’m not saying it’s impossible that there be another deviation from the base model of the solar systems we see all around us that just might permit complex life, but our system is freakily deviant. The galaxy’s a big place, there could be others. But not many. The chances of there being many more planets as serendipitously favoured for civilisation as ours is unlikely.
Winning the lottery degrees of unlikely. At least.
The universe is trying to kill you
And the factors piling up to prevent the invention of the iPhone do not end there. Did you know that, about nine thousand years ago, our species very nearly became extinct? Had there been an paleolithic endangered list, we’d have been on it. We survived, coming back from a population equivalent to the size of a larger comprehensive school. That was another reboot.
Here’s yet another factor – it was only about 12 thousand years ago that food production emerged. Simply put, farming. It was that transition from hunter gatherers to farming that made room for literacy, architecture, engineering and, eventually, science. Without food production, there is no food surplus to support thinkers, poets, experimenters, inventors. No civilisation. No iPhone. So, in the greater scheme of things, civilisation is very recent.
Our species is about 200 thousand years old, but civilisation only showed up in the last 5% or so of that. Then remember that only in the last 100 years, or less, really, have we understood the hostile environment in which our poor blue marble sails. It’s likely that we’d have seen a rock coming in 1923 but we couldn’t have done anything about it. It’s just about possible that if we saw the rock coming today that we just might be able to do something about it, but that’s been the case for only a couple of decades. And wevd be lucky to pull it off, with or without Bruce Willis.
Had a rock come our way during the second world war, game over. And if it came today, all we’ve got is a fighting chance.
The more we learn about our world, its place in the universe, and how we got here, the more it becomes apparent that the predicates of the Drake Equation are wildly false. Our planet is not a good rule of thumb, it isn’t normal, it isn’t the standard by which we can reasonably measure the galaxy. It is, in fact, especially lucky.
We are deviants. We’re weirdos. We’re disappearingly unlikely.
So, someone must be looking out for us!
Some have taken these factors as proof of divine intervention. Obviously, they say, the creation in a week thing is just an allegory, but, they say, god did manipulate nature appropriately to engineer our special place and us. So, metaphorically at least, the universe does revolve around us.
I prefer, always, Occam’s razor. In the absence of solid evidence, the simplest explanation is usually the right one.
So here it is: we won the lottery.
Someone had to.