| Mere interplanetary invasion - attack from | | | | the immediate origin of the invaders in this novel |
| another world of our own Solar System - is hard | | | | is Titan, the suggestion is that their ultimate origin |
| to plot plausibly, given modern knowledge of the | | | | is interstellar). |
| unlikelihood (in fact the virtual impossibility) that | | | | A perhaps even more ingenious solution to the |
| any other world circling our Sun could harbour a | | | | problem of plausibility can be found in Larry Niven |
| technological civilization which might pose a threat | | | | and Jerry Pournelle's novel Footfall, and also in |
| to us. But what about invasion from another star | | | | Stephen King's The Tommyknockers. The stories |
| system? | | | | are very different - in Footfall the invasion affects |
| Here the problem is different. It's plausible enough | | | | the whole world, in The Tommyknockers it is local |
| to imagine that starfaring species exist out there, | | | | in impact and is defeated by the efforts of one |
| and that one of them might want to grab Earth | | | | man. But in both of these novels what gives us a |
| for their own use. But if so, how could we | | | | chance against the invaders is the fact that they |
| possibly make a fight of it against a race | | | | are in a sense "freeloaders" or scavengers, who |
| advanced enough to have conquered interstellar | | | | have stolen or inherited a spacefaring technology |
| space? Wouldn't it be so one-sided as to furnish | | | | which they could never have invented for |
| scant material for a story? The tale, it seems, | | | | themselves. |
| would be one of destruction rather than invasion. | | | | They are nevertheless formidable opponents, and |
| Rather like a human army versus an anthill. | | | | the reader can feel a proper awe at the |
| One possible answer might be that a race from a | | | | immensity of the task of defeating them. But at |
| dying planet, wishing to change worlds, might be | | | | least the idea of resistance is not utterly ridiculous, |
| so few in number that our vastly greater | | | | as it would be if we were fighting the actual |
| numbers might compensate for our equally vast | | | | originators of the starships. |
| technological inferiority. This is perhaps the | | | | All the examples I have given also deal effectively |
| rationale for the old TV series The Invaders, | | | | with another possible objection - namely, the |
| starring Roy Thinnes. | | | | objection that races advanced enough to master |
| Another possible answer is that the foe might be | | | | star travel would also be advanced enough to |
| essentially parasitic, with no need for its own | | | | refrain from imperialism. I'm not sure that the |
| civilization; it merely infiltrates the host culture and | | | | argument is conclusive in any case, but certainly it |
| turns it against itself. This is what happens in R A | | | | need not apply if the users of the starships are a |
| Heinlein's classic The Puppet Masters (which I | | | | desperate few, or parasites, or the galactic |
| count as a tale of interstellar invasion, as although | | | | equivalent of delinquent joyriders. |