We should expect alien civilizations, if they exist, to quickly expand and colonize the galaxy. If they exist, they should already be here in our own solar system, mining the Sun, harnessing its entire output via a giant arrangement of solar collectors enclosing the sun. Their existence would be blatantly obvious. All we would have to do is look up and see, with our naked eyes, enormous engineering constructs in our solar system.
These constructs, however, do not exist. Furthermore, we can be certain they also do not exist around any other stars that we can see because, well, we can see the stars. If our solar system were spared from this fate for some reason, our nighttime sky would still be completely black.
The implication is obvious. There are no alien civilizations in our solar system, so there aren’t any anywhere. At least, there are none close enough in time and space to have made it here yet. For example, if an alien civilization developed one billion years ago in a galaxy two billion light-years away, then they would not have been able to have spread here yet. The laws of physics cannot be broken, not even by a super-advanced civilization.
But assuming they do still exist, why haven’t they done this? I honestly doubt that they would be hiding. If I were a super advanced civilization going about the universe this way, I probably wouldn’t bother hiding. What would be the point? Any developing civilization would probably eventually end up competing for the same resources. Indeed, I might be inclined to wipe them out before they could be a threat in order to secure my own survival.
And that raises another excellent point. If an alien civilization did evolve far in the past and colonize the galaxy, why are we still here? The fewer civilizations that have access to resources, the longer each civilization can survive. Plus, by constructing a Dyson swarm, they might even have deconstructed Earth for materials. Similar to the previous question: why is Earth still here? Not that that’s necessary to use Earth for materials. There’s likely enough material in the asteroid belt to make a Dyson swarm, but since there are more materials laying around, you might as well use them too (plus if you remove the planets and are left with only the swarm, you no longer have large masses gravitationally tugging on your collectors causing them to drift out of their orbits).
Then again, maybe they did exist, but died out before they had a chance to colonize the galaxy. Maybe there have been many civilizations which have all died out. This paints a rather unfortunate future for ourselves if true. They might even have sent precursory robotic probes throughout the galaxy as stated in Part III, but then died out before continuing. If so, there might still be alien base orbiting the Sun, or an alien base set up on some asteroid, waiting to someday be occupied by beings that no longer exist.
There is another mystery that galaxy-colonizing aliens seem, at first glance, to solve: dark matter. There is a large about of matter in the universe which we can detect gravitationally, but which does not shine or absorb light, rendering it, effectively, invisible. Maybe there really is a galaxy-spanning civilization harvesting the starlight of most, but not all, stars, and the ones we see are the small percentage.
To be honest, I don’t think that is what is really going on. If that were the case, we should still be able to detect their waste heat. There would be a very large number of anomalous heat sources crowding the sky, outnumbering visible stars by 9-to-1, and we would be left with the paradox of why such a civilization would choose 90% of the stars in the galaxy and leave the other 10% alone.
But that line of logic leads to what could be called a prediction of my hypothesis: find a galaxy, or cluster of galaxies, which are unusually dim, and/or radiating lots of infrared and radio light, but not visible or higher frequency light. Freeman Dyson essentially proposed the same thing-looking for anomalous heat sources in the sky-but predicted only point sources within our own galaxy. Here, I am predicting extended heat sources, perhaps actually covering significant portions of the sky, at hundreds of millions of light-years’ distance.
In the end, I think that the most likely state of affairs is that there are no extraterrestrial civilizations in our galaxy, neighboring galaxies, or within several hundred million light-years. This is pretty depressing thought, being alone. But it’s also one of great opportunity: we made it! We’re the first! The vast resources of the universe are ours for the taking! We have won the comic lottery, so to speak. At least, we will if we are able to band together, act in a unified fashion in order to ensure our own survival, instead of spending most of our resources finding new ways of killing each other.
But to be honest, I think we do have what it takes. In 1950, the idea that human civilization would last until the year 2000 was uncertain. There were many who thought the odds were the human race was on the brink of extinction. But today, the idea of the human race surviving to 2050, 2100, 2200, and so on seems much more believable. Global superpowers have learned, it seems, that working together is much more productive and desirable for all of the human species. In the words of Carl Sagan, who had fiercely argued against nuclear proliferation, “perhaps we have, after all, chosen life.”
So what about all other current efforts to find extraterrestrial life, namely SETI? SETI is searching for extraterrestrial radio broadcasts, perhaps beamed to us deliberately or “leaked” accidentally. So far–obviously–they have found nothing. Under my hypothesis, this result isn’t very surprising. They haven’t been found because there’s no one there. If they really wanted to relay information to us it would likely be through a probe already stationed in our own solar system, one which would have been there throughout all of human existence.
But does that mean I think that such a search is a waste of time? Absolutely not. Science is, after all, grounded in observation and experiment, not theorizing. My hypothesis could be entirely wrong, and could very well be disproved by SETI by discovering a single instance of extraterrestrial intelligence. I whole-heartedly support their efforts and, given the circumstances, really wouldn’t mind being proven wrong. If my hypothesis is right, we are the first sentient species to colonize the galaxy, and if I’m wrong, we have other intelligent species in the universe. Either way, I win.
Next Chapter: Additional Thought