No matter how smart a writer or a reader is, he's never going to be as smart as Reed Richards, Lex Luthor, Hank Pym, or Tony Stark. Those guys make the aforementioned 16 year old doctor look like a citizen from the film Idiocracy. When the writer is writing for a younger audience on one of Marvel or DC's kid-friendly titles, they can get away with a bit more, but when writing for the teen and older comic book audience, there is almost certainly going to be someone reading the writer's work that lies further along that intelligence scale than the writer, and they're going to be able to pick holes in a super intelligent character's actions and speech. However, this problem can be managed, to an extent.
|The Negative Zone is never |
going to make sense
The second kind of ties into the first: have someone else read it. If you can, have several other people read it. I'm not saying "have other smart people read it," either. Yes, have someone who understands the field read it to make sure you got it right, but also have regular people read it to make sure you are getting what you mean to across. Unless your goal is to make the character sound so much smarter than anyone else in the room, and your plan to convey that to the reader consists of confusing them with things that sound like science, it's as important that the readers understand both that the character is brilliant and why they're brilliant. It does no good, normally, to have all of the technobabble to go over the reader's head.
Third, apply this to other types of intelligence as well. Cyclops' role on the X-Men was supposed to be field leader, and he was called a tactical genius all the time. However, his plans usually came down to "Don't have our guy made of metal take on Magneto." Thanks, Napoleon. I guarantee that you can find someone who is actually tactically smart to bounce ideas off of, even if you have to explain what Cyclops and Colossus and Magneto can do to them. Batman used to have similar problems with criminology, but the rise of CSI-style police procedurals on TV made the average reader and writer familiar enough with forensic science and other fields that they get the basic ideas of what Batman is doing and why; it still speaks to his intelligence, but now it doesn't fall into any of the traps of over-explaining, under-explaining, or just completely getting the science wrong.
|He knows, for example, that this is a dead body|
As I said before, even with extensive research and preparation, certain readers will know that the supposedly brilliant character isn't acting as smart as he should be. However, the more preparation you put into writing for a smart character, the closer you can get to writing him as intelligently as he is supposed to be. And, as a side bonus, you might learn something yourself.