Saturday 23 November 2019

Book review: Rendezvous with Rama

I've just re-read this for the first time since childhood - at least I don't recall reading it since. Links: wiki, Goodreads; Graun. I won't trouble you with the story since you'll find it there.

As usual this contains spoilers so read no further if you haven't already read the book.

In contrast to Transition, I liked this. It's good old fashioned (literally...) "hard" sci-fi. What it does rather well is keep the mystery going for as long as possible; in that, it's kinda like 2001. The problem with almost all sci-fi is that ultimately there are no answers. Of course there aren't; if there were, it wouldn't be fi (alternatively, there are answers, but they're dull). So the trick for the author is to keep up the sense of wonder for as long as possible. So, ultimately, there are no answers and we never learn what Rama is for or who built it (some people find this dreadfully disappointing, but they're wrong). In a sense the book is just an exploration of what a space-ark might be like from the point of view of the people it was going towards; and Clarke just mechanistically goes through the various steps; but he does it well.

Some niggles: if you find a circular sea in a cylinder and the bank on one side is much higher than the other side then the very first thing that will occur to you is that the high side is where the engines are, especially if there's a six km spike pointing out from that end. It's kinda necessary for the story that this isn't realised for a bit, I guess for the non-physics-competent readers, but it annoys somewhat (having just posed the question to E it turns out that she couldn't think of the answer). Exploration: they walk everywhere; well, they didn't bring bicycles. But then when it's necessary to cross the sea they have a wheeled cart to transport the raft materials, and an electric engine for the boat (where did they get the propeller from?). So the idea that they wouldn't have constructed some kind of powered cart seems implausible. Also, I got the idea about jumping into the sea, after some thought.

The idea that Rama was detected so late now seems rather implausible; I suspect even our level of tech would probably see it way out. But, I forgive that, as it very nicely leads to there being only one ship able to get to it, and we're spared all kinds of tedious complications that would have added nothing to the story. Others note that it's implausible that they wouldn't have done metallurgical analysis of the outside, and that's true, but on the other hand that too would have added very little to the story. It's also implausible that they wouldn't have got some kind of powered flight going. Towards the end, in the "missile" episode, they suddenly have a space scooter. Surely they would have disassembled that, taken it through the air locks, and used it inside to get to the South Pole  much earlier.

There's an implausible tech-level mixup I think. For most of the book Rama is mysterious, but doing physically obvious and comprehensible things: moving in accord with the laws of physics, taking 200 kyrs to move between stars. But then suddenly at the end it starts to acquire new powers: a reactionless drive, the ability to produce a vast mirror shield, and affect the sun. This seems curiously unnecessary. If you have that level of physics tech then the entire idea of a generation ship starts to look less plausible.

Lastly, this huge mysterious thing that's travelled for 200 kyr and presumably intends to voyage much further is nearly nuked by the Mercurians. There's no hint that the skin is nuke-proof, and the nuke-not-going-off is entirely contingent, so this was somewhat careless of the builders. And it becomes clear that anything this big and predictable is actually rather vulnerable. In which case not-very-much-thought points out some counter measures that you'd take: don't allow anything to approach carefully. In the book, Rama kinda springs to life and warms up as it goes around the sun, but really there's no reason automatic systems wouldn't wake up somewhat earlier (the book maintains for as long as possible the uncertainty about whether the things are alive, biological, or robotic; and to be fair in those far off days computing power was weak; but, still). Like, outside Neptune's orbit. And you'd scan the radio spectrum and... what? Know that there were people there? And you'd shoot down - or at the very least attempt to warn off - anything approaching. Just trusting that all would go well is not believeable. You'd also in all probability have sent ahead a swarm of probes, and so on.

Ah, and lastly, it seems unlikely that it would spend 200 kyr voyaging to the sun just in order to use it for a course correction/ boost; surely there would have been somewhere nearer to aim at. I'm not sure why he felt it necessary to make it so long; perhaps just to increase the sense of awe. Oh, and one very last thing, while it's most efficient to do boosts near a gravity well with a conventional reaction drive, I'm not at all sure that would be true with the Raman non-Newtonian drive. Sadly the book doesn't explore this point (Rama instead sucks up some sun material, so it does have another reason for getting close).

Another thought added later: one reason the book is fun is that effectively it's a puzzle book; a bit like a murder-mystery, but with (physics) puzzles throughout, like the cliff; it is possible to reason about the situation (even when it goes wrong). One reason that books like Transition disappoint is that they can't be thought about or reasoned about, because the plot twists are arbitrary.


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