A few months back a bunch of you all pitched in to help me figure out some FTL issues, and this time I’m asking for your scientific expertise on a subject a little closer to home. Er, sort of. I don’t think this is going to be too spoilerific, but if you’re concerned you can stop reading here!

In a nutshell, I’m trying to figure out exactly what the Galaxion can know about the planet below from up in orbit. From a plot point of view, there are things they can know and things they can’t. Or at least, temporarily can’t know. I’m not even thinking about fantastic new technologies here, I suspect even with our present level of tech they could learn quite a lot.  Telescopic lenses are the most straightforward way of seeing what’s happening on the surface—that’s how Google Maps works, seeing stuff from satellites in orbit, and I believe the level of detail could be a lot higher. I can probably guess at the sort of limitations of a regular lens—the line of sight will be blocked by physical obstructions and will also be poor on a cloudy day.

Infrared sensors are another method of gathering surface data, but one I don’t grok quite as well. I understand with infrared imaging you can see stuff outside the range of human vision, such as the radiation from heat sources. I know astronomers use infrared telescopes to learn things about faraway stars, so using it to learn stuff about a planet you’re orbiting should be easy stuff. Movies and TV frequently show characters using some sort of thermal camera to clearly see people hidden in a building or behind a wall. How accurate is that? Can it be done from orbit, through the interference of the atmosphere? Could Fusella, on the Galaxion, be able to accurately track the positions of the Survey Contact Team? How about if they went inside a building? Or the Hiawatha? How much could clouds and other weather events mess up their ability to gather data? How about metal? Or rock?

I’m sure there are other methods of gathering data that haven’t even occurred to me. Some will likely not be important at all to the plot, but would be nice to at least think about. If you have any suggestions for me, I would be most grateful!