In the world of DC comics, which is more of my home (I enjoy some Marvel books, but I'm more a tourist there: DC is more my neighborhood), there has been some confusion.
In 1985, writer Marv Wolfman and artist George Perez created the Crisis on Infinite Earths event.
Other places cover the nitty-gritty of the Crisis in detail better than I can, but I'll give some context.
In 1938, DC invented the comic book super-hero with Superman. The publishing house actually was originally three publishing companies: National Allied Publications and Detective Comics were by the late 1930s basically the same company, and All-American Publications. All three eventually started publishing lots and lots of super hero comic books. Eventually, it was decided that all of those superheroes lived on the same fictional Earth. This was the so-called "Golden Age of Comic Books." It ended by the 1950s.
In the later 1950s, DC/National/All-American (now publishing under the name National Periodical Publications, which would be the company's official name until the 1970s) hadn't been publishing any superhero books--aside from Batman/Detective and Superman/Action and maybe Wonder Woman--for a few years, and decided to revitalize some properties. Instead of just using the same characters, many of whom had magic or fantastic elements to their origins, a more science-fiction-like approach (science fiction being the next big thing) was taken with all new characters who just happened to have similar super-hero names as previously published superheroes. This proved popular with the revitalized Flash (now police scientist Barry Allen instead of college student Jay Garrick), and was tried again with Green Lantern and a few others. Eventually, Barry Allen discovered that Jay Garrick actually lived on a parallel Earth with a different "vibrational frequency."
Thus was the concept of multiple Earths born, and DC comics was no longer a universe, where all the superheroes lived and interacted in the same fictional reality, but a Multiverse, and the number of different Earths was believed to be infinite.
Over the next two to two and a half decades, DC would publish an annual cross-over between the superheroes of the various Earths. These were titled things like "Crisis on Earth-Two," "Crisis on Earth-Three," and so on. Also, as DC Comics bought superhero characters from folding or defunct publishers, they would sometimes create a new Earth for those characters to have always existed on: the Fawcett family of Superheroes (Spy Smasher and Captain Marvel and his family) existed on Earth-S, while the "action heroes" of Charlton Comics (Captain Atom, the Question, the Blue Beetle) lived on Earth-4.
Eventually, it was decided that this was confusing, despite the fact that decades of children had been reading comics with the multiverse concept and having little to no problem understanding it all. Perhaps they meant confusing to new adult readers, an audience that comic publishers have been trying to tap into for a long while. At any rate, the higher ups at DC were becoming more and more dissatisfied with having to explain the multiverse every time it was mentioned, and Marv Wolfman--a writer who had grown up reading comics--was working for DC, wanting to put his own mark on the company, and pay homage to those favorite cross-over stories. A grand plan was designed: a new Crisis on Multiple Earths, but one that would bring in every character DC owned, had published, and maybe even a new crop of characters DC would publish in the future. Tying it into the concept of removing confusion that DC wanted, getting rid of the Multiverse would be the major plot of the series. Everyone hoped that they would clean up the continuity of DC comics and a new era of comics publishing--a new Golden Age--would arrive.
It didn't entirely work. Oh, sure, the multiverse was gone, but there was no agreement between varying editors and group editors on what the shape of the new single universe would be, resulting in things like Hawkman's history being completely rewritten time and time again without a satisfying conclusion for years, or Wonder Girl's origin being tossed out due to events in the Wonder Woman comic. DC tried again and again to repair the damage, with varying degrees of success: Zero Hour allowed editors to rewrite one point in each title, but again a lack of editorial agreement screwed things up again; eventually the concept of Hypertime was created as a band-aid, really: all continuities, even out-of-continuity Elseworld titles that couldn't ever fit, or potential stories that would never be written, all of them existed, and would sometimes send ripples back into the "main continuity," the main timeline, the mainstream.
Nobody was entirely satisfied, and I don't like Hypertime for various reasons that I'm not going to get into right now. Basically, it was a bit of a mess, but for a while DC was willing to ignore it if most of the readers were, too.
Eventually, it was decided to throw that philosophy out again. DC is still in the middle of Infinite Crisis, a series that--hopefully--will finally correct the meandering continuity, and it is hopeful, because the guy in charge has gotten all the editors to communicate, and hopefully agree on the future shape of the DC universe.
But, of course, it's not at all that simple.
In the course of Crisis on Infinite Earths, a constructed Earth, made up of Earths 1, 2, 4, S, and X was created. Because of events in the series, it is sometimes . . . well, okay, often believed that these are the worlds that make up the Earth that existed after the Crisis on Infinite Earths, oftentimes called Post-Crisis Earth, or Earth-mixed.
Or Earth-screwed-up, for the cynics.
Well, the problem is that other events in Crisis contradict this theory. You see, there was time travel involved. The universe was reset. Things not pretty happened.
I haven't yet mentioned this, but I hate time travel. Nobody ever thinks it all the way through, or they do and create crappy stories because they spend all their time thinking of the time travel aspect and ignore the story itself.
Anyway . . .
The Post-Crisis Earth wasn't just constructed of Earth 1 (the silver age Superman world, where Barry Allen was Flash), Earth 2 (the golden age Superman world, where Jay Garrick was Flash), Earth 4 (Charlton Comics world, home of Captain Atom, the Question, Blue Beetle), Earth S (Fawcett Comics world, home of the Marvel family and others), and Earth X (a world where the Nazis won World War II, and several heroes from long-dead comics publisher Quality Comics). No, you see, this world is, according to text in CoIE, the world that was always supposed to be: there were no other Earths, so aspects of "multiverse" Earths are reflected in this new Post-Crisis Earth. One of these multiverse Earths is the newly revealed Earth-8. Earth-8, the new continuity fixing event Infinite Crisis claims, is where new heroes would have been created had CoIE not occured.
But those heroes did come into being.
On the mainstream DC Earth.
Wow. That's a lot of context.
Aaron "The Mad Whitaker" Bourque