Funding X-COM

For those that don’t know, X-COM is a series of games and associated media set in an alternate present-day Earth and deals with the workings of a multi-national agency with the specified aim of defending Earth and Humanity against alien aggressors. It might sound like an odd thing to be wondering, but should we – as a species – be considering funding something similar? I’m not going to go too far into the realms of conspiracy theory, so for the sake of argument, we’ll assume that humans have had no contact with any kind of extraterrestrial intelligence and that we have no knowledge of their being any life outside of what we know of on Earth.

However, the absence of evidence isn’t the evidence of absence: just because you can’t see something, that doesn’t mean it isn’t there. Native African and American tribes would have had no idea that European settlers were on the way to their homes, but that didn’t stop the Europeans from going there. And this leads me neatly into another point: we have first-hand experience of what happens when a more technologically developed society meets a less developed one. We could hope that any society which had evolved enough to develop technology which allowed them to travel between the stars had put thoughts of colonialism and slavery in their past, but a quick examination of our own history tells us that this need not be the case.

All of this leads back to my original question: should we be funding a real-life X-COM department or agency?

In order to answer this in any really meaningful way, we would need to consider two pieces of scientific reasoning: the Drake equation and the Fermi paradox. The former deals with the likelihood of intelligent extraterrestrial life existing within our galaxy, while the latter deals with the likelihood of that intelligence ever having visited Earth.

Before we can consider the Fermi paradox, we need to think about how many civilisations might be out there in space right now. Back in 1961, scientist Frank Drake – the founder of SETI – came up with this formula:

This states that the number of civilisations in our galaxy (N) with which communication might be possible is equal to:

  • R – the current rate of star formation in our galaxy
  • fp – the fraction of those stars that have planets
  • ne – the number of those planets that could potentially support life
  • fl – the fraction of those planets that could support life, that go on to develop life at some point
  • fi – the fraction of those planets developing life that go on to develop intelligent life
  • fc – the fraction of those intelligent civilisations which develop technology which makes them detectable across space
  • L – the length of time such civilisations broadcast such detectable signals into space

This seems like a complicated formula, but lets take a closer look at the parts in order, and plug in some numbers.

It might seem strange to talk about the rate of star formation, rather than the total number of stars in the galaxy, but phrasing the equation in this way means that, without the inclusion of L at the end, you can calculate the number of new civilisations being “born” each year. Then by multiplying that number by the length of time those civilisations broadcast detectable signals you can work out how many civilisations there might be active at any one time.

So, how many stars are being formed each year? Well, the latest estimates from NASA indicate that the galaxy creates 7 new stars per year, so we’ll stick with that.

Next we need to know what fraction of those stars will have planets. There’s data to support the idea that every star has planets, but our current technology only allows us to confirm the existence of very large planets, or planets that orbit very close to their parent stars. This is because we detect planets by looking for a drop in the level of light emitted by the star when a planet passes between the observation points on Earth and the star itself, and this is much easier to detect with larger planets, and close-orbiting planets. With that in mind, we’ll take a somewhat pessimistic view that 40% of stars have planets.

Now we need to know what fraction of those planets are habitable. This estimate will be a proverbial shot in the dark as we have yet to conclusively find a habitable exoplanet, and hence have no benchmark to work from. One of the major stumbling blocks for estimates for the number of habitable planets is that they all consider a habitable planet to be Earth-like: orbiting in the “habitable zone”, large enough to retain an atmosphere but not so large as to accumulate gasses and become a gas giant, regular temperatures, not being tidally locked, active plate tectonics to keep things mixed up, a large moon for tidal action and perhaps gas giants in the outer star system to shield the planet from asteroids. Personally, I believe that we will eventually discover life on planets which are not at all like our own, and there are certainly a number of people who believe that Earth is practically unique in the whole universe when it comes to the criteria required for supporting life. With so little data to work from, lets go with a NASA estimate of 5.4% of those planets being habitable.

Next question: how many of those habitable planets end up with life on them? I’m going to be optimistic here and say 100%. This is often the value used when working through the Drake equation due to the rapidity of life occurring on Earth when asteroids stopped slamming into the planet every few thousand years.

Next, how many life-bearing planets go on to develop intelligent life? We have evolutionary evidence, both in our current biosphere and with certain dinosaurs to support the idea that intelligence – or, at least, a high encephalisation quotient – is something that multiple species trend towards. We’ll work with 50% for this figure, accepting that intelligence is something that will be selected for evolutionarily, but that any manner of natural disaster could befall a species before it reaches this point.

Now we have to ask, how many of those intelligent lifeforms manage to develop a level of technology which makes them detectable through space. For the purposes of the value, we’ll say that “detectable through space” simply means giving off artificial electromagnetic radiation, so if you can make a radio, you’re there. Lets use a value of 90% for this: technology gives so much benefit to a species that I think all intelligent life will inevitably get there, barring some form of major disaster.

Finally, we have to ask how long these civilisations remain detectable. This is usually phrased in a frightening way, meaning how long before a civilisation is destroyed. This need not be the case, however. A look at our radio output over the last 30 years has seen it decrease significantly as we have moved away from inefficient radio broadcasts to other forms of technology which don’t require pumping EM radiation through the air. Even so, we have had radio technology for around 115 years, and have been actively broadcasting for around 110 of those, so lets go with that for our final figure.

So, if we plug all those numbers into the equation, we get a result of 7.48 (or 7.5, rounding up) civilisations communicating in our galaxy. That doesn’t sound like much, and given the vastness of the galaxy it means that the nearest civilisation to us is probably 16-18 thousand lightyears away, which means that it would take 32-36 thousand years to get a radio signal there and to receive a reply. Which makes it all seem kind of pointless when we look at the length of time a civilisation exists, or uses radio-based technology.

Even so, there are some flaws with this system. The Drake equation is merely an estimating tool: we had to make quite a lot of guesses and assumptions as we worked through it and if you plugged in very different numbers for your inputs, you would get a very different result. The final flaw is that this estimate of civilisations assumes they occupy only planet or star system and they haven’t gone out and colonised other planets or star systems. Perhaps these civilisations have colonised their corner of the galaxy and we just haven’t noticed, or perhaps there is something else going on. We’ll cover this in the next part, discussing the Fermi paradox.

Phew! That was a tough slog, huh readers? Well, from the above segment we can take a rough guess that there are around 7-8 civilisations active in the galaxy at any given moment. And that the nearest civilisation to us is around 16-18 thousand lightyears away. Now, given that any civilisation which can build technology which allows them to cross such vast distances (a single lightyear is around 5,878,625,000,000 miles…) is likely to be so far in advance of us that funding a modern military defence force to fight them is pointless, which leaves us thinking that the nearest threat to us is too far away or too superior to really worry about. But, as we discovered above, one of the biggest flaws of the Drake equation is that it only accounts for civilisation occupying a single star system.

So, why don’t we just add another variable into the equation to estimate how far a civilisation expands over time? We could, but doing so leads us straight into the Fermi paradox. Developed by physicist Enrico Fermi whilst working with colleagues at the Los Alamos National Laboratory, the paradox attempts to explain why we haven’t made contact with any extraterrestrial civilisations.

He found himself wondering thus: given that the sun is a relatively young star (its about 4.6 billion years old; the galaxy is around 13.7 billion years old) there must have been other civilisations which came before ours. If those civilisations had colonised their home systems, and sent out colony ships to other stars, which then sent out other ships – even at slow speeds and the rate of one every thousand years, they’d have colonised the whole galaxy in less than a billion years. Lets look at the maths…

Imagine that colony worlds are 10 lightyears apart, and that colony craft can move at around 0.02% the speed of light (which is the fastest we have been able to accelerate our craft to). Now lets say that it takes a colony 1000 years to send out another wave of ships, this means that the colonisation front is moving outwards at a rate of 0.00019 lightyears per year. Given that the galaxy is 100,000 lightyears across, this should mean the entire galaxy would be colonised in around 526 million years. This is quite a pessimistic estimate: if you increase the colony ship speed to 0.1% the speed of light (a highly plausible speed given near-future technology) the whole galaxy could be colonised in around 11 million years. It might seem like quite a long time to a human who lives less than a century, but in terms of the deep time the universe operates on, this is less than the blink of an eye.

This means that the entire galaxy should have been colonised repeatedly over the billions of years it has been in existence. Even our own Earth, which has been able to support some forms of life for around 3.8 billion years, should have been visited over and over again, yet as far as we can tell, this isn’t the case. Fermi realised that even if, for some statistical anomaly, Earth hadn’t been visited yet, the galaxy itself should be a far noisier place than it seemed to be. This left him wondering just where everyone was.

As we have seen above, its not unreasonable to have seven civilisations with the capability for interstellar communications – meaning the production of radio waves – active in the galaxy at any one time. This is more than enough to have the Fermi paradox take effect, so how do we reconcile these two? In reality no one knows, though there are some theories:

  • The Earth is unique in the galaxy – in my opinion this is statistically quite unlikely, but it comes up all the time.
  • Civilisations don’t ever leave their home system – while it would be technologically difficult for a civilisation to do, I have a hard time accepting that its never happened before. However, one of the key inputs into the Drake equation is the lifetime of an advanced civilisation. If that number is below the amount of time required to muster the resources required to start colonising other worlds, it would help to explain why our galaxy was so quiet. Of course, any civilisation which managed interstellar travel would be so much less likely to go extinct for some reason that if it happened even once, we’d likely run straight back into the Fermi paradox.
  • Civilisations choose to stay in their home system – either the economic or material costs are so high as to prevent interstellar colonisation being a realistic option, or the interest to pursue that line of development just isn’t there. It may also be that there are unforeseen difficulties which make interstellar colonisation unworkable, even with an entire solar system’s resources. However, given our own penchant for insane feats of colonisation, I have a hard time buying wholly into that one, too.
  • We are being protected – often called the “Prime Directive” hypothesis, it states that advanced civilisations exist and are potentially all around us, but are shielding us from the knowledge of their existence. It strays into the borders of conspiracy theory, but given that humanity has tried (and singularly failed) to do this with groups of tribes in the Amazon, I’m sceptical about this too, but it remains a possibility.
  • They are already amongst us, and the Governments of the world are keeping a security blanket on it – definitely in the realms of the conspiracy theorists, I don’t buy into this one at all. I’ve worked for the government for a long time, and I genuinely don’t believe they have the capability to keep a secret that monumental.
  • We’re just looking at things in the wrong way – this makes the most sense to me. Most of our searches for alien life tend to focus on radio waves and other electromagnetic emissions. If another civilisation had developed a communication technology using some method which we don’t understand, we might not detect it even if it was flooding around us all the time.

There are other possible solutions to the Fermi paradox, but those are the most common ones that don’t stray too far into the realms of conspiracy theory.

So where does this all leave us? Take another look at the Drake equation and think about where our estimates could be wrong, and the equation break down in such a way as to leave us in a quiet universe. Should we be funding X-COM? That all depends on what you believe: that there isn’t anybody out there, or that they’re just keeping us all in the dark while they prepare their attack…

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