I have an idea for an alien invasion of Earth novel that's been rattling around in my head for a while. The first chapter is written and some notes in rest in a file, and I have a general idea not only where the story will start but where it'll go. But there are pieces of the plot that need filling in. This process sometimes takes me a while.
For example, how could mankind fight back? How could they threaten alien spacecraft in orbit above Earth? Nuclear missiles? Maybe not so much. Without the atmosphere to carry the shock wave, the damaging effect of nuclear blasts are much diminished. Plus, how easy would it be for an advanced technology alien species to target and destroy a missile, approaching a spacecraft?
What about lasers? Again, atmospheric-driven diminished effectiveness. And any aircraft rising 30,000 to70,000 feet to eliminate atmospheric degradation would be very vulnerable to attack, even with decoys accompanying it--if any and all could be built and launched. And a lot of power generation would be needed...? Probably not a viable option.
Then, I remembered a clip I'd seen on a show on the Discovery Channel a few years back. It discussed Thunder Wells. That sounded promising. So a little research and there it is. A limited yet potentially effective way humanity might strike.
In essence, a Thunder Well requires a long shaft drilled into the ground, the shaft filled with water, which is instantly heated/vaporized upon detonation of a nuclear device at the bottom of the shaft. If the shaft is plugged with a metal projectile (shot out by the immense steam pressure) that could survive traveling 40+ miles per second through the atmosphere until it reaches space...and strike an orbiting ship...
Targeting might be a problem, along with a few other issues...but it has potential.
Thus, one gap in the plotline filled. Only a few more to go.