>>> Item number 14186 from WRITERS LOG9306D --- (134 records) ---- <<< Date: Wed, 23 Jun 1993 17:00:03 JST Reply-To: WRITERS Sender: WRITERS From: Mike Barker Subject: TECH: favorite sf bloopers Favorite SF Bloopers (Outer Space) Science fiction writing, unfortunately for the writer, often involves writing about science. Not that you need your Ph.D., but it helps if you don't make elementary bloopers. Just for fun (and to help you avoid them) here are some of my favorites concerning outer space. Incidentally, since these are just the ones I could remember easily, I'm sure I've missed several other common ones. If you have a favorite, send it in - we can all use the help. 1. Decaying orbits The scene is familiar, but let me fill in the correct ending. Power failing or gone, the ship... will continue to orbit indefinitely. If you wonder why, consider the moon, or Earth itself. Despite completely lacking in drive engines of any kind, they just keep on orbiting. Now, if you want to use this "ticking clock," there are some possibilities: a) the ship is in a very low orbit, already inside the atmosphere. This orbit will "decay", as friction removes energy. b) the ship is in an artificially forced orbit, going faster than it should for the small orbit (for a fast survey?). And when power fails, it moves farther out, perhaps to collide with other orbiting ships or material or maybe just becoming detectable to pursuers. c) the ship cannot correct course after power fails. This could mean it will fail to enter the correct orbit, will collide with something, or otherwise have problems caused by continuing when it should have turned, slowed, or speeded up. d) air (movement or recycling), heating or cooling, and other systems necessary to sustain the life of your characters can fail. While it may not be as visually spectacular as burning up in atmospheric reentry, choking, broiling, or freezing are quite adequate threats to the life of your characters. However, be careful of my next favorite goof (the dreaded infinite cold of outer space). BTW - the same problem often threatens rotating space stations - having lost power, they grind to a stop. As does the story, for me, because there is no necessity to keep supplying power to a rotating body in space. Just like the Earth, it just keeps on spinning, unless something counteracts it. Now, you might slow down (or speed up) as ships connected... but simply losing power will not change the spin rate. However, please don't pay attention to the Captain when he claims that if power is lost, our orbit will start to decay. He only has an hour to defeat this week's lumpy headed aliens, so he can't waste any time threatening you with the real problems the power loss will raise... 2. The infinite cold of space... "Exposed to the vacuum of space for a few seconds, the instantly frozen rose cracked into a thousand shards at his touch." Well, someone has paid attention to the shows with liquid nitrogen and other coolants. However, vacuum is an excellent insulator (as demonstrated by thermos bottles). It reduces the loss of heat due to conduction. Admittedly, water or other liquids will evaporate, producing a cooling effect, but in general items exposed to space will tend to hold their temperature. If exposed to sunlight or other sources of radiant energy, they may even rise significantly in temperature. The drying and depressurization effects are significant enough - don't add in the "cold of space", because vacuum doesn't have a temperature. 3. Zero-gee (or lower gee) weightlifting "In low gee conditions, he lifted the ship easily on one finger." Mass stays the same. I.e., to move that ship, he should be able to move it anytime. He might start it moving (slowly) with one finger or stop it moving (again, slowly) with one finger, but simply changing gravitational fields does not turn it into a balloon. One quirk to this - lower gee does significantly change frictional interactions. For example, a table leg that would be normally stable against sideways pushes under normal gravitation might be quite slippery under lower gee. Moral - think carefully about whether the character is working against mass or gravitational effects. One never changes, while the other does. 4. Retrograde Planets and the Magical East-West Intuition "He looked at the sun rising in the west and felt the oddity of reversed directions." Maybe. First, though, let's take a look at "east" and "west." I think these can be defined a) in relation to where the sun rises and sets (i.e. in relation to the direction of revolution, which defines north/south poles, also) b) in relation to the magnetic poles c) in relation to the direction of orbit around the sun The normal meaning of a retrograde planet is one whose revolution or spin is opposite to the direction of orbit. E.g., when you look at the orbit of the Earth around the Sun and the direction of spin of the Earth, they both go the same direction. Now, does being a retrograde planet affect the first common usage of "east" and "west"? NO! The direction the sun comes up is east, and the direction it sets is west. Simple, and under most conditions, anyone on the surface of a planet is likely to use this meaning for these words. Does being a retrograde planet affect magnetic poles? I have to admit, I'm not sure about this, since I don't know exactly what creates the magnetic fields. However, if the magnetic poles are related to spin, the likelihood is that again, the person on the surface of the planet is unlikely to notice any discrepancy. You might use this, although very few people really pay attention to compasses. Aha! A retrograde planet does, indeed, redefine east and west when compared to the directions defined by orbit around the sun. In fact, that is the definition of it. But, is someone on a planet likely to notice this? It is possible (by noting astronomical phenomena over time), but relatively unlikely. It took our own people quite a while to get around to the notion that the planet orbits the sun... Now, I will grant that the visitor from space may have been told that the planet is retrograde. But, I submit, once on the planet's surface, the likelihood of noticing that is slim, and the sun will rise in the east, and set in the west. If you really want to have some wonder, play with the lunar orbit(s), or those of the other planets. What happens when the moon(s)'s orbit is counter to the spin? Or what happens if two planets orbit in different directions around the sun (stability may be low, if they are relatively close, but...)? OK? Ready, set, now write - and avoid these bloopers. mike