Not very likely. Not here, anyway.
Today, I’m going to try in my laym layman’s terms, to explain why we aren’t likely to be visited by little green men.
We are all of us steeped in the Star Wars mentality of our time. We see people traveling through space as if it’s as easy as a trip to the store in the family car. Rationally, we know that it’s a little more difficult than that. If we’ve thought about it at all, we know that it’s very cold in space and the distances are quiet large. But how large are they?
Alpha Centauri is the nearest “star” to our own sun. It isn’t really a star – it’s three stars: two are somewhere close to the size of our own sun, A and B, and the third, or C, is a much smaller object. To get there, a space craft would have to travel about 4.37 light years, a light year being the distance light can travel in a year at 186,282 miles per second in a vacuum. Traveling at light speed is impossible, and I’m not really sure what speed is really possible. For one thing, space is not empty. It’s not very full, either, but it only takes one very small object to make a real mess of a craft traveling at high velocity.
So, imagine that we could reach speeds of 1/2 the speed of light. Ignoring the consequences of traveling very fast, such as aging more slowly than people on a relatively stationary planet (I know – they really move along through the universe at a good clip), we would have to travel for at least 8 years to get there, and we have no idea what we’d find. We haven’t discovered any planets there yet as far as I know and it would be rather silly to send people there just for a quick look.
But it gets worse. Even if we could travel at something like half the speed of light, we have to first accelerate to that speed, and then decelerate as we approach the planet. Our journey has gotten longer. There’s the consideration of what kind of engine or fuel would be sufficient to handle such a trip. How large a craft? What about food and water and purification and so forth?
And everywhere else is even further away.
One can imagine otherworldly creatures who are more intelligent than us and far more advanced, but imagining such things and their actual existence are two vastly different sorts of things. Perhaps there is an upper limit to intelligence. We have no idea what the limits of evolution might be. Perhaps at a specific stage of intelligence creatures just become suicidal. (You know, like we are.) Perhaps all so-called intelligent species burn up their resources before they can get away from their respective planets. And perhaps the speed of light is not really the limiting factor – it might just be that other factors prevent our traveling at anything approaching light speed.
And by ‘us,’ I mean ‘them.’
Looking at the vast ocean of hundreds of billions of stars in our own galaxy, one wonders how you might find your way. We have developed our sciences so far so quickly that it’s difficult to assume that there may be limits to it. On the scale of solar systems, planets are as invisible as a grain of dust in a windstorm. But, let’s assume that our wayfarers are clever enough to map their journey before they begin, and know exactly where they’re going. We might even assume that these creatures have perfected viewing machines that can see details on a planet in another solar system. The next big leap is where they start from.
Because there is no reason to think that every solar system that contains planets also contains intelligent life. And there is no reason to think that every planet that contains intelligent life contains life as intelligent as we are. And there is no reason to think that a planet with intelligent life is immune to strikes by other celestial objects. So it is reasonable to assume that any intelligent life that has the ability to travel over long distances might also be a very long distance from us. And it is equally likely that there are a great many stars as close to them as our own and therefore many choices as to which direction to travel.
I’m not personally capable of working out the odds of the likelihood of nearby intelligent life, but I’m betting that there isn’t any. No matter how prolific life is in the galaxy, it’s taken us four and a half billion years since our planet was first formed to even realize that the stars were places we could even travel to! And that’s yet another problem: just because we are here and now, we have to realize that other civilizations may have already come and gone, or may be hundreds, thousands , or millions of years from reaching a level of intelligence such as we have. There is no reason to think that all things happen everywhere at the same rate.
It’s not impossible, of course. Perhaps life is more likely among the stars on the outer arms of a galaxy than near the center. Maybe other stars in our “neighborhood” developed at much the same time as our own. And it could be possible that cosmic collisions sort of average out. Maybe there are planets with intelligent life almost as close as Alpha Centauri. Now we have to assume that there would be some reason that they would want to spend the time and resources necessary to travel to Earth. Not only is it expensive in terms of any imaginable lifespan, but there is serious danger to the travelers and even to their place of origin supposing they find other intelligent life that also happens to be warlike and even more advanced than themselves. No sense waving your arms and shouting, “Here we are! Come and get us!”
But who can see into the mind of aliens? Imagine their disappointment after coming so far only to find that we’ve just about reached a tipping point where life here will no longer be possible. What a disapointment!
And those sightings? Those UFOs? Well, we don’t call them unidentified for no reason. If they were spaceships, we’d call them spaceships. Until we began to get some idea what the cosmos is, we used to call them angels or demons and the sightings were just about as common as they are now. People have always looked up at the sky and imagined what horrors might come from it. Relax. You’re pretty safe.