What is up with the different Earths? Like what’s importance of Earth2 which I hear about a lot. Does each title from the new 52 get its own Earth (so 52 Earths altogether?)
DC have had the multiverse as a concept for a long time. The idea of a second earth, for example, was used to explain how the Golden Age (30’s – late 40s/early 50s) related to the Silver Age (50’s – 70s roughly) of comics. We had Batman and Superman fighting in and around the WW2, so how could those guys still be young in the 60s? Easy – those older stories happened on a parallel earth!
Now, the multiverse got big and complicated from here. Want to create a story outside the current continuity? Just say it happened on another Earth! It allowed a lot of freedom and then different worlds even crossed over and met one another. This is all heavily involved in the various Crisis stories – the multiverse has been destroyed, recreated in a similar but not exactly the same way (to allow writers to change some bits but keep what they like, really) and more, but…
…that doesn’t have much importance for how the multiverse matters in the New 52.
In the New 52 we know there is a Multiverse because it’s been mentioned in stories and by DC, however all of the New 52 titles, except for Earth 2, take place on the main DC continuity Earth, which is now called Prime Earth (not to be confused with Earth-Prime from pre-New 52, but I won’t go into that). Prime Earth is also, importantly, a combination of disparate DC, Vertigo and WildStorm universes – like how Stormwatch is now part of the main DC continuity – but the short story is it’s just where all stories, unless otherwise indicated, take place.
There are some more details – the Power Girl and Huntress from World’s Finest are actually the Supergirl and Robin from Earth 2 who accidentally ended up in the main reality when Darkseid attacked Earth 2. Also, Mr Terrific from ‘our’ side ended up over there. Also, the main Batman and Superman met their Earth 2 counterparts in a flashback story in the first issues of Batman/Superman. That’s not all though if you followed Trinity War and Forever Evil then you’ll know that the Crime Syndicate are invaders/refugees from yet another Earth, designated Earth 3.
As far as the wider Multiverse goes, it hasn’t been explored a lot but with the Earth 2: World’s End coming up and lots of mentions of certain events in Futures End, it’s bound to be more relevant. Also, Grant Morrison’s Multiversity starts this month which will be two bookend issues and a series of one shots, albeit with an overarching plot, journeying through various world in the DC multiverse.