Subject: I have SCIENCE!!!
Author:
Posted on: 2013-10-23 13:35:00 UTC
I'm not sure I'll be able to continue your chemistry analogy, but here's what I know:
There are three kinds of crossovers - the two you mentioned, and the type I call "Holodeck" - basically, one continuum is kept fictional and someone in the other continuum is a fan. Some continua play well in certain types and not in others. Some continua play very well with others.
There are three levels: Plays Well With Others, Plays With Friends, and Plays Best Alone.
Examples:
Plays Well With Others:
Star Trek
There are three reasons:
1. Random weird things in space that connect to other dimensions
2. Holodecks
3. Time Travel
The risk is that your continuum really wouldn't appeal to any characters, and the others can be overused. Star Trek doesn't play as well with magical continua, but I've found that if you explain something in a way that sounds vaguely scientific it fits with the universe. They literally managed to justify turning some characters into kids.
Of note is that Next Gen and Voyager play well with MLP:FiM, because DisQord.
Doctor Who
This is the most friendly continuum I have found, because it involves a device that can literally go anywhere in time and space. The risk, again, is that it can be overused.
Plays With Friends:
Harry Potter
Harry Potter plays well with other magical continua, especially others set in World One, like Percy Jackson. Unless the laws of that universe directly contradict the laws of Potter-verse, it can work. It's not particularly compatible with sci-fi due to the canonical "magic and tech don't mix" rule.
Sherlock
It plays well with other continua set in World One, and has enough outlandishness to let fantastical continua like Potter or Avengers meld with it. Better with sci-fi than Potter, but the sci-fi continuum has to be the one providing the means of transportation to the other continuum.
Plays Best Alone:
Lord of the Rings
It's not possible to share a setting, and there aren't really ways for characters to leave the universe. I used to think the elves were sailing to some vague nondescript place that could be another continuum *cough* Vulcan *cough*, but I seem to recall reading somewhere that their destination is actually specified. In order to get characters there, you need your other continuum to be a friendly one.
It's important to remember that "holodeck" type is very easy as long as:
-The other continuum would actually appeal to the characters of the other continuum. For example, a Star Trek/BBC Sherlock crossover of this type is plausible, while a Star Trek/Twilight crossover is not.
-It would be possible for that fiction to exist in universe. For example, Star Trek characters can play LOTR on the holodeck, but LOTR characters can't watch Star Trek.
That's all I've got. SCIENCE!!!