It is 100 years since the Tunguska event, when a meteor/black hole/badly piloted spaceship crashed into Siberia, and exactly what happened remains a mystery.
Which is convenient for science fiction, because you can plausibly have a micro black hole floating around under the Earth's core, or the Death Ray experiments of a mad scientist. (Steampunk meets World War 1 on the Eastern Front, anybody?)
Most popularly, of course, Tunguska has become an integral part of UFO mythology, including being involved in the 'black oil' arc in the The X Files.
I have no idea where this is leading in terms of Christian sf, except that I kind of like the idea that when Lucifer fell from heaven, he landed in early 20th Century Siberia. (If I'd been a little more on the ball I would have actually written that story already, but I've been excercising my gift for procrastination instead.)
The whole UFO thing, though, has facinated me since I was a yoof, so I may explore that a bit. Or I may just sit and watch some X-Files. Yes, I think that's more likely.