As science fiction and science approach one another

 kw: book reviews, nonfiction, popular culture, films, television, science fiction and science

For many of us, when we are not thinking about food, work, or sex, we're thinking about space. Those who are lucky enough to work in the field think about, in order, space (work), space (dreams), and then the others. One such is Ariel Waldman, who has gathered the content of conversations and interviews about her favorite subject into her new book Out There: The Science Behind Sci-fi Film and TV.

The book's 19 chapters introduce subjects ranging from escaping Earth gravity to loneliness, from spacesuit design to starship speculations, and from what alien creatures and their languages might be. I'll touch on a couple of items that I found interesting.

Chapter 5 is titled "Artificial Intelligence – Should spaceships be sentient?", and is headed by this evocative illustration. Some of us remember HAL, the conflicted, eventually homicidal shipmind in 2001: A Space Odyssey. In science fiction, intelligent machines are most frequently presented as risky or downright dangerous. Not all, though; at the end of Isaac Asimov's Foundation/I Robot series of intertwined stories, R Daneel Olivaw has attained near-deity and is quite benevolent, but such depictions are rare.

I've read stories in which the shipmind is a brain grafted to machinery (the best is "The Ship Who Sang" by Anne McCaffrey), others with human minds downloaded into computers, others with purpose-built AGI's, and many more with no technology indicated.

Here's my take on conferring all power upon a mechanism: If it is based on biological neuroanatomy, it will not be any more reliable than are we, or pigeons, or whatever bio-brain is modeled. If it is based on familiar multi-CPU/GPU-OS architecture, it has a better chance of being reliable, but it will be less relatable. I suggest that command-and-control be based on utterly reliable hardware, and that the "ship shrink" and other artificial companions be separate from it.

Chapter 9 is titled "Asteroids – What's so interesting about a bunch of space rocks?" So far, all the asteroids that have been visited by spacecraft are more akin to rubble piles. The idea of hollowing out an asteroid to make a habitat must await our finding some that are more solid. 

Metallic asteroids such as Psyche (the target of a spacecraft, also named Psyche, that will arrive in 2029) are thought to be quite solid, with little surface rubble. Others may have a large-ish solid core, with "shells" of rubble up to several or many meters thick. Psyche's size is about 278km×238km×171km; it is one of the largest asteroids. Good targets for mining or other uses will be less than a kilometer in size.

A quote by the author is apropos: "The idea of asteroids as human habitats might not be as alluring as the fantasy of living on the Moon or Mars, which would be unbelievably challenging environments to make a home out of, but they are an interesting option." I am not sure if the phrase "unbelievably challenging" was intended by the author to refer to the Moon and Mars, or to the asteroids. I'd put it this way, that if it is 100 times as hard to make a livable habitat in or on Mars or the Moon as on Earth, an asteroid habitat would be a further 100 times as hard as the Moon to live on or in.

Also, the people who advised the author put to rest the idea that the "asteroid belt" is awash with dangerous rocks that one must dodge when attempting to traverse it. Many spacecraft have zoomed through the whole depth of "the Belt" at speeds of thousands of km per hour, without mishap. Not so much as a grain of sand, so far as we know, has hit any of them. 

Think of it like this: The total mass of the main belt between Mars and Jupiter is about 3% of the mass of the Moon, which is 7.348 × 10²² kg (Wikipedia article is here), and the four largest asteroids make up about 60% of that. The next million known asteroids bring the total mass of "bigger pieces" up to about 99% of the expected total mass.

Suppose that all the rest of the total mass were grains of sand with a size of about 1mm, weighing 2.5 mg each. Divide that into 0.012% of the mass of the Moon; it comes to a lot of grains (it's a 25-digit number). Then, the belt itself can be treated as a torus with an inner radius of 290 million km and an outer radius of 500 million km, which is halfway to Jupiter from Mars, so its volume is, very roughly, a 9 followed by 24 digits, in kilometers...I'll forego putting the calculations here. Dividing the volume by the number of grains I find 24. Each virtual grain has 24 cubic kilometers to itself, on average. Calculating the "expected impact cross section", the number of grains a square meter of spacecraft is likely to encounter passing through the 310-million-km thickness of the belt, I find 0.32 expected impacts.

That is interesting. It is larger than I would expect, considering that no spacecraft have been damaged while traversing the asteroid belt. It also emphasizes that some of the estimates in the prior paragraph could be very far off. At any rate, it is unlikely that anyone aboard a spacecraft on its way through the belt will ever see anything, unless they purposely pass by a known asteroid.

The subjects are all interesting, and I could write about my reactions to all of them. But this is a review, not a synopsis! It is a small book, in its own way, but well worth reading. Small: the pages are large, but the paper is thick so there are only 134. Each chapter has a full-page illustration like those shown above, and a full-page title, plus a page of some halftone-dot pattern; all that subtracts 57 pages from the total. It is still worthwhile.

I must also applaud the artwork of Phil Wheeler (this is his agent's website). I've included just two of his illustrations for this book, but I was strongly tempted to provide thumbnails of them all.