Gimp. Armageddon onto a photo

Hi, I am new to Gimp and I am looking for a tutorial in how I can create an Armageddon onto a photo that I want to use. I have found several fireball and asteroids about to hit earth but want to find more detailed tutorials on creating an end of the world theme. I am using Gimp 2.6.12, and I have not added any plug-ins (as I tried but do not how to go about it, but that is a different thread).

Many thanks

Without wishing to sound too smug, I think we can predict the menu for the next five years at Robert Bast’s ‘Survive2012’ Australian hideaway: tinned beans, tinned beans, bottled water and more tinned beans.

The same goes for thousands of others who had expected to be the only remnants of today’s scheduled termination of the human race. Like Bast, a well-known ‘survivalist’ and online prophet of doom, they have been leaving nothing to chance.

But it’s always the same with this blasted Armageddon business. You take all the right precautions, you abandon your job and go to an enormous amount of trouble to set yourself apart from the common herd in the confident expectation that you are a Chosen One.