The CW has cornered the market on superhero series with no less than four comic-based shows on the air, but one of these shows is not like the others. While Arrow, The Flash, and Legends of Tomorrow all take place in the same universe, Supergirl is set in another entirely. The big four-part crossover will see Barry Allen recruit Kara out of her world and bring her to Earth-1 for the first time to help her battle the Dominators. The Flash executive producer Todd Helbing has come out and shared which Earth in the multiverse is Kara's, saying this:
No longer will we have to say "Kara's Earth" or "the Supergirl Earth" or "the CBS Earth." Now, the Earth formerly known as Kara's has officially been designated as Earth-38. For those of us who watch all four shows in The CW's superhero lineup, Todd Helbing's reveal that Kara hails from Earth-38 is pretty fabulous news.
I'm not sure how the folks at The CW chose 38 as the number for the Supergirl universe, but it could be a nod to the fact Superman made his comic book debut in 1938 as the first major superhero. Arrow and The Flash certainly haven't been shy about using 52 as a nod to The New 52 revamp of DC Comics. Supergirl wouldn't exist without Superman, so Earth-38 could be a solid way to honor the superhero who started it all.
We've already seen there are an awful lot of differences between Earth-1 and Earth-38. Aliens aren't an accepted part of daily life on Earth-1, and heroes like the Flash and Green Arrow don't even exist on Earth-38. Still, there are some key cultural and political similarities. Supergirl executive producer Andrew Kreisberg has also teased that the Dominators that will plague Earth-1 in the crossover will return to The CW on Supergirl later in Season 2. The arrival of aliens in the crossover may mark the beginning of Earth-1 becoming somewhat more like Earth-38.
A big question now is whether or not Earth-1 and Earth-38 will remain separate in the long run. Arrow, The Flash, and Legends of Tomorrow borrow characters from each other on a semi-regular basis for mini crossovers that are usually pretty fun; such mini crossovers aren't as easily doable with Supergirl taking place in another universe. It's possible that The CW's multiverse will someday be condensed into fewer Earths for the sake of convenience. DC Comics did it with the "Crisis on Infinite Earths" storyline. Who's to say that something similar won't happen to bring Kara and her pals in National City to live on Earth-1 on a permanent basis? It wouldn't be the first time that a CW superhero show tackled a huge comic storyline.
Personally, I'm perfectly happy with Arrow, The Flash and Legends of Tomorrow all part of Earth-1 while Supergirl is part of Earth-38. Tune in to The CW tonight at 8 p.m. ET to see The Flash leg of the big DC TV crossover that brings folks from the two Earths together. For a look at what else Flash executive producer Todd Helbing has to say about the event, head on over to the next page and check out the video.