“For every complex problem there is an answer that is clear, simple, and wrong” – H. L. Mencken
Douglas Adams once said, “Technology is a word that describes something that doesn’t work yet”, but we place enormous faith in the inevitability of technological progress, sure that our scientists and engineers can eventually solve all problems involving natural law. Heck, somebody’s got to be working on an app for that. They’ve got a pretty impressive track record so far, so perhaps our confidence is not entirely misplaced. For those of us born in the 70’s, we were raised on healthy doses of Star Trek, Star Wars, Battlestar Galactica, and stacks of science fiction that made it seem that the expansion of the human race out into the galaxy was a foregone conclusion, and that we would one day meet other sentient creatures and swap stories was just a matter of somebody’s technology making the great leap into the future of faster-than-light travel. Once we started landing people on our own moon and hurling space probes into the void, visits from extraterrestrials started to seem a lot less far-fetched. The absence of any definitive proof that the aliens are among us in the form of direct contact has led to speculation regarding a deliberate effort to obfuscate, ranging from abductions for the purpose of genetic harvesting to the Zoo Hypothesis, but we seem to intentionally neglect the most obvious reason that we have not and may never have any kind of intercourse with extraterrestrials, that is, the galaxy is a really big place, stuff is very far apart, and the natural hurdles to interstellar travel may simply be insurmountable.
Astronomers estimate there are roughly 100 billion stars in the Milky Way Galaxy, suggesting that there could easily be as many as 8.8 billion habitable Earth-sized planets orbiting other stars. That seems like good odds. The nearest multi-planet solar system to us happens to be Gliese 876 and it is 15.3 light years away (about 145 trillion kilometers). That means that, travelling at the speed of light, it would take us over 15 years to get there. Not too shabby for intrepid explorers such as ourselves, except for that whole travelling faster than light thing. According to most physicists, matter, of which we and anything we build are inconveniently made, has a “subliminal” speed limit. The problem is that as you get close to light speed, the energy required to move even a little bit faster basically becomes infinite. Even when you get near the speed of light, weird stuff happens to matter and energy anyway. There’s the whole time dilation thing with thousands of years passing on Earth relative to the short amounts of time for our astronauts. You also wouldn’t be able to see very much due to aberration (the narrowing of your visual field into a tiny tunnel). Oh, and at such speeds, should you happen to run into an atom out there in space, it will tear a hole in your ship. That’s a lot of inflight patching, assuming everything just doesn’t fall apart from the wear and tear and you wind up sucking vacuum.
Thus, a lot of hope centers on wormholes, or Einstein-Rosen Bridges, a hypothetical topological feature that would fundamentally be a shortcut connecting two separate points in spacetime that could connect extremely far distances such as a billion light years or more, short distances, such as a few feet, different universes, and in theory, different points in time. It sounds suspiciously like a warp drive. Cool, except for the fact that most physicists say it would wreak havoc with matter, and you wind up as an undifferentiated ball of plasma on the other end. Given the natural barriers to getting up the speed or shortening the distance, the hopeful mutter about “generation ships” designed to raise successive generations of explorers in a closed environment, so that the descendants of the original crew will ultimately arrive at the desired destination. Assuming of course, the ship survives that long, they don’t murder each other, they manage to figure out how to keep providing enough food and water, and anybody remembers why they set out in the first place.
Now, maybe we will triumph over these obstacles someday, but as we are a relatively young solar system in an extreme backwater of the Milky Way, had anyone out there ever solved the problems inherent in interstellar travel, we would expect to have heard from them or at least seen some busy extraterrestrials moving about out there in the great beyond. Unfortunately, the deafening silence out there in the universe would seem to suggest that nobody has quite figured it out. Don’t get me wrong, my fingers are crossed, and I’m hoping for a warp drive, but one must consider the possibility that given the distances involved, even if there are sentient critters loitering about in the galaxy, they may simply be keeping it local. Johannes Kepler said, “When ships to sail the void between the stars have been built, there will step forth men to sail these ships,” but what he didn’t reckon was the question of whether they would ever get there. After all, the older I get, the further away the corner grocery seems.