For instance, the main armament on HMCS Borealis is a pair of 6-inch (152mm) railguns that use magnetism to accelerate projectiles to ludicrous speeds. Naturally I needed to know how much kaboom would be exerted per shot (many kilotons) as well as a reasonable expectation of engagement range (thousands of kilometres).
I also wanted one of the alien races to be cold-blooded. They come from a cold planet, and their body temperature is near freezing. Would it be possible for such a race to exist? Could they be warmed up, so they could
This started as an idle Googling at 8pm, and one thing led to another and it was 3am and I was reading a fascinating article about our friend the humble cuttlefish. It lives quite successfully in near-freezing water, with copper-based hemocyanin in its blue blood in the place of iron-based mammalian hemoglobin. It can even be warmed up to human body temperature, if done carefully.
Another such Googling-Gone-Wrong evening found me reading about the sex lives of Tetrahymena thermophilia. This curious species of bacteria has not two, but seven distinct sexes. Each of them can successfully mate with any sex other than their own, with the offspring having various probabilities of being each of the sexes.
That's one of the awesome things about science and science fiction. You can dream up whatever strange alien lifeform you want; chances are, something a lot like them is already here on Earth.