[X] My Assistant

[tacitus]

Hi, I've just written the first draft of a science fiction short story and I need little help with the plausibility factor . Since many highly educated people hang out in this forum (flattery will get me everywhere... I hope!) I thought this might be a good place to ask a few questions.

The story is about a colossal creature (think Titan-sized, as in the moon Titan) that lives amongst the stars, travelling from solar system to solar system, hibernating while in between. (Hey, I didn't claim it was original .) I'm not so concerned about the plausibility of such a species evolving as I am about how the creature is powered.

The creature's internal systems are powered (for want of a better word) by a fission reactor, which I think is okay. But its propulsion is powered by the burning of hydrogen and oxygen (i.e. as in rocket fuel) extracted from water - and this is the bit I'm unsure about.

I know hydrogen and oxygen can be extracted from water, and with a colossal nuclear reactor at its core there is enough energy for the creature to do so, but I just don't know how plausible this whole propulsion set up it. (I guess I can live with "unlikely", I just don't want to base the story on something that's "impossible".

An important aspect of the story as it is written is that the creature needs to stock up on its water supply and has to munch on moon-sized objects to do so (think Europa-sized or smaller in this instance). So its critical for the story that water, and the need to replenish its supply of water, plays a very large factor in the creature's life. I know we are talking colossal sizes and amounts of water here, but that's part of the nature of the story.

So, what do you think? Am I on the right track or careening off the rails?

Any help at all would be greatly appreciated.

Thanks,

Mike

[tacitus]

Sorry I've been away for a while - that was not my intent!

Anyway, thanks for all the suggestions and pointers. It seems that superheated plasma is the way to go as far as a propulsion system is concerned, and since getting such a large mass moving at speeds that will get it from star to star in at least a few hundred years would need a huge amount of fuel (mass) to accerelate it.

Yes, I think a fission reactor is more plausible since they do occur (abeit in a limited way) in nature, and water could be used as a regulator as well as mass for the accelerant. In fact, since heavy water reactors can be used (along with natural uranium) to power the fission, perhaps there's another need for water (heavy water is present in sea water - 1 in 3200).

Of course a fission reactor would, as you point out, need nuclear fuel. My assumption was that perhaps the creature would not need to refuel its uranium at every stop, but would have to restock its reaction mass, so bypassing (conveniently) the need to worry about that .

The story is told from the creature's (fairly limited) POV, with the point being that if and when alien life encounters us (or vice versa) they might be so alien that they might not even recognize what we are, much to our detriment!

Since this is a short story I don't want to get too bogged down with the details (as long as they don't beggar belief). If I was writing a novel then I would certainly have to nail down the details since there would be more time in which to do so.

If I ever get it published (a long shot, for sure) I'll let you guys know!

Mike