The Science behind the stories
From the Author:
One of the first things that springs to mind in Xiantha is the phenomenon of second sound. This is not about sound at all, but refers to heat transfer in superfluids, where the heat is transferred in waves, rather as if it were sound. I thought this was a fascinating concept, and wanted to use the idea, wanted to imagine what that would feel like if second sound were happening in an "ultrafluid" which would have many of the same properties as a superfluid, but at a higher temperature. You can find out more about the real "second sound", and how it went from a prediction to solid science, here
The Xianthes themselves are taken originally from Miranda, which has smaller, but similar "mountains" reaching up into the sky. The sprites and elves exist here on earth, as you can see here:
Representation of upper-atmospheric lightning and electrical-discharge phenomena. This is above earth. For Xiantha, imagine them multiplied by four!
(This image is taken from the Wikipedia page, and is attributed to Abestrobi.)
Here is a widget that tells you which planets will be visible in your night sky today. Unfortunately it doesn't list the Ammonite Galaxy!! ...