10 April 2011

Why this is not (yet) the Space Age; and why the Star Trek universe does not and cannot exist

More than a year ago now I promised my correspondents and blog readers to essay an explanation, as I put it then, for Why this is not (yet) the Space Age; what a Space Age might actually be like (and why the 'Star Trek' Universe does not and cannot exist). Sorry for the delay, in the unlikely event anyone was actually waiting for it.

I'm not truly prepared to go into all this comprehensively, but I have read a fair amount that touches on the physical realities that circumscribe this issue, and have what I hope is a fairly realistic grasp of what the limits and parameters actually are. So I'll take a stab at explaining those points. There are really two topics here: Space Flight Near the Sun, and Interstellar Travel. Both have limiting factors that most people, even people who like to watch Battlestar Galactica or such like, don't really understand. 

I will leave out for now much in the way of commentary about What a Space Age might actually be like; leaving that for a later speculative post.  

1. Solar System Space Travel and Colonization.

Back in the 50s, 60s and 70s it was blithely assumed by many people, some of whom actually did understand the physics and chemistry of space flight and rocketry, etc., that the very difficult problems associated with the energetics and economics of even near-Earth and intra-Solar System space flight would be readily solved, and that we as a civilization really were on the verge of an Age of Space. People like Gerard O'Neill and many “hard science fiction” writers pictured space colonies in orbit around the Earth and the Sun by now. Colonies on the Moon and Mars were seriously envisioned, and whole schemes for terraforming (making more Earthlike) at least Mars, were devised and discussed seriously. Projections were drawn up whereby the all but prohibitive cost of lifting even modest masses (like the mass of a person), off the surface of the Earth and into space, would come down, in much the same way that the cost of computer power and memory has been exponentially reduced.

This has not happened, and there are no indications that it is about to. The essential problem is that, unlike information technology, space travel requires a lot of expensive energy, a lot of expensive equipment to make it possible for human beings to survive in a really, really inhospitable environment, and a lot of time. Even within the Solar System, apart from near Earth orbit, which is reasonably accessible, especially for unmanned vehicles (although still quite expensive to get to), everything is very far away by terrestrial standards. And not only that, but moving. So, while the computations of celestial dynamics are quite tractable with computer assistance, it takes a lot of “delta-V,” which is space talk for energy necessary to change your velocity to match that of your destination, and a lot of time, to get anywhere. And space is dangerous. It's full of lethal radiation, and you have to take everything you're going to need with you. It's proven to be inordinately expensive to send humans into space for any purpose at all, and the costs have not dropped significantly. Only governments, with huge resources and no need to show economic justification (usually) can even attempt it. Sure, there are some private ventures hoping to send rich assholes into space for pure ego-trip reasons, but I discount that as non-serious. Economically, widespread human space travel just isn't to hand.

Now, will it ever be? Sure. There are potential technologies, like space elevators, and exotic propulsion ideas, that will no doubt eventually result in humans being able to use space for more than just machines like satellites to provide TV signals and imagery of Earth. Even colonies in orbit, or on Mars or the asteroids. I don't doubt it'll happen, but it's not about to happen. This is not the Space Age. We have the capability to launch satellites and robot probes to explore the Solar System, and to put humans in orbit or possibly, at huge expense, even send them to a planet or two, just to show it can be done. But there will be no significant living in space or colonization of space, anytime soon. The bottom line (that hated expression) is that for now, it's just too damn expensive. 

Another point: as my uncle pointed out to a younger me when I was arguing for the concept of space colonization, why would we consider the vast cost of colonizing orbit, or the Moon, or Mars, when we haven't even found it economically justifiable to colonize the surface of the ocean, or Antarctica, where there is readily available, breathable air? The concept of space colonization, for the foreseeable future, just doesn't make economic sense.  

2. Interstellar Travel.

Even more remote is the prospect of traveling “to the Stars.” It was a favorite meme of classic Science Fiction that technology would solve the truly intractable problems of sending anything, (even information traveling at the speed of light) to “the stars.” I used to read, back in the 70s and even 80s, about various ideas, such as “Bussard Ramjets” (see Wikipedia article), “ion drive,” “laser drive,” etc. that might make interstellar vehicles possible. Some optimists, like the scifi writers Jerry Pournelle and Larry Niven, wrote how the curve of technological advance should reassure us that pure science theoretical breakthroughs would probably happen, and the problem of practical interstellar travel would probably be solved by the end of the 20th century. Hmmm. Not so much, it would seem.

The problems of energetics and economy of space travel within the solar system are exponentially increased with interstellar distances. Those very distances, combined with the hard facts of physics, make it utterly infeasible, in fact, for travel of anything physical to other stars in anything like a fraction of a human lifetime. The best technology that now exists, irrespective of cost, could not transport even a minimal dead weight to the nearest star in less than, at minimum, a millennium or more. Even signals traveling at the speed of light take years, if not centuries, to reach potentially interesting destinations “out there” in the Galaxy.

One of the reasons, of course, is the fact that interstellar distances are so very, very great. See this, which comments on this.

Star Trek and other science fiction is partly based on the fanciful postulate of various means of traveling faster than light, such as “warp drive,” “hyperdrive,” “star gates,” “wormholes,” etc., but none of these is really anything more than wishful thinking, at this point. No one has the first clue how to actually do this, in the sense that Benjamin Franklin might have at least been able to conceive of transporting electricity through a wire to do useful work. We can’t even really intelligently speculate, at a conceptual level, how any kind of “FTL” could possibly work. What’s described in fiction is really just magic.

And this is unsurprising. Because, in reality, traveling, or even communicating, faster than light can traverse space, is actually impossible, for a variety of technical reasons. Not only is it impossible, but it is the logical equivalent of traveling backward in time, which creates logical paradoxes. Why this is so is complicated. This article, which assumes at least a certain fluency in the conceptual language of science, does a pretty fair job of explaining this.   

Then there is the Fermi paradox, which I already discussed here. Think about it. If, as most people assume, the universe fairly regularly configures itself in such a way that intelligent life evolves and reaches a technological level more advanced than we are now, wouldn’t it follow that, if it were actually possible to travel faster than light and visit large numbers of stars in short periods of time, then others would have preceded us and done this? It’s easy to calculate that if a civilization existed even for just a few tens of thousands of years with this capability, it would have time to visit every single star in the Galaxy. So, if this kind of interstellar migration and colonization were actually feasible, at some time in the billions of years that the Galaxy has been in more or less its present form and configuration, someone would have already done this, which would mean that they had been here, to Earth. The evidence that this has never happened is not absolutely conclusive, but, on the other hand, there is absolutely no reason to conclude that it ever did happen either, so you’re left with at least some reason to conclude that interstellar travel and colonization, while not theoretically totally impossible, are not easily accomplished. And the concept that even if it ever does occur or has occurred, elsewhere in the universe (which I imagine it has), it has not involved the ability to travel faster than light. Instead, it has been a very long-term proposition undertaken only by the most advanced and mature civilizations.

Which we aren’t. And which we won’t be, I’ll venture to say without much fear of being proven wrong, for a good, long time.

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