I am currently writing a post-apocalyptic novel This Broken Earth. When creating a post-apocalyptic world, a writer needs to base the environment on events that could possibly happen in our near future. Readers need to see the post-apocalyptic world writers show them and nod their head in agreement, not scratch their head wondering how the writer's created world suddenly came into being.
I use several internet resources to check the science of my science-fiction. First of all, I have a few consultants with whom I am able to ask specific questions. I have spoken to a climatologist, an Army Captain, and my good friend Michael Dean who is a phenomenal science teacher and researcher. I have also used some of the following resources:
1. Meteor Strike Calculator - Do you need to know what would happen if a meteor were to crash into the earth? Go no further than the Earth Impact Effects Program from Purdue University. There are several fields to fill in such as how far your characters are from the impact, the size of the meteor, its density, air speed, and whether it strikes water or land. When all information is entered, simply click calculate effects and this engine will produce the meteor's possible effects.
2. Nuclear Fallout Calculator - Ground Zero from Carlos Labs is another calculator that will give a blast radius and fallout radius for a nuclear blast. Simply choose the place on earth to be nuked, choose from a wide range of nuclear devices and then click "nuke". Users will get a nice map of the blast radius and fallout pattern.
3. Zombie Outbreak - Not that this is scientific at all, but Ottowa University students created a mathematical modeling of a zombie outbreak infection. It has everything one needs to mathematically determine the results of a zombie outbreak if it were to occur in the real world. It is complete with formulas and rationale. The only think it does not have is a shambling gait.
4. Plague - The City of Berkley has produced a website that details all the information at a glance about a pandemic flu outbreak. It answers all questions one could possibly ask about the subject, including how fast it would spread, what governments would do, and all of the detailed medical information that a writer would need to tell a story set in such a world.
5. How to Survive the Apocalypse - Of course characters will need to know how to survive the apocalypse, and Survive the Apocalypse has all the information one would need for such a task (even if the information is sometimes tongue-in-cheek). It is full of survival tips, videos on everything from swine flu to nuclear fallout, and is also a good laugh when boredom sets in. (Not that you should be bored, writer. Get to writing).
6. How Long Does It Take? - I did some research to find out how long it would take to travel per mile on foot, horseback as well as horse-drawn carriage:
Foot - 50 miles per day. It would take 3 months to cross the United States barring injury or obstacle.
Horseback/Horse-drawn carriage - It depends on the pace but most horses pull a carriage at 3-6 mph. from New York to California is roughly 3000 miles. At a slow pace that is 1000 hours or about 41 days. At a faster pace that is about 21 days if traveling non-stop. Horses must also stop for the night and rest. Figure that it would take at least a third of the time in rest, feeding, and care. 1/3 of 41 is about 13 days so it would take about 45 days. Factor in that by horse it can take 1-3 weeks to cross a mountain range since pace can be as slow as 1 mph or less and would be roughly 51-66 days of travel. It would be about 2 months of travel stopping for rest only assuming nothing goes wrong. Old wagon trains of the west had to stop for hunting, cooking and crooked roads, etc. The straight roads help such as highways (if they haven't been destroyed). Without a straight cut path, a trip across the United States would take 4-6 months.