Stephen Amell released a tweet today showing the 90’s version of the Flash with its actor John Wesley Shipp back in the ninety’s version of the Flash costume for the CW’s Elseworlds crossover event.
— Stephen Amell (@StephenAmell) October 22, 2018
No, you aren’t mistaken, Shipp also played Jay Garrick, a version of the Golden Age Flash on the modern version of The Flash as well. And that’s Stephen Amell in a version of Gustin Grant’s red uniform, and that’s Gustin Grant on the right in Stephen Amell’s green suit. That’s Melissa Benoist on the far left, of course.
How is this possible? Because DC uses a form of Universe construction called a Multiverse. A Universe is a collection of all the stars, planets, and adjacent realities, called dimensions accessible from within a particular person’s reality.
The DC Multiverse is a series of parallel worlds, which are similar in the occurrence of metahuman potential and it is this potential which binds these worlds together. Thus you will find there are several Earths which have similar entities or capabilities and often share names such as the Flash, which appears on Earth-1 in the 2000, or on Earth-3, thirty years before.
While no particular reality is more “real” than any other, for the sake of convenience, the Flash television show starting in 2014 has been designated Earth-1. Jay Garrick now resides on Earth-2, a world slightly different than our own.
There are thousands of “nearby” parallel worlds which can be reached with the right technology or superhuman abilities. But travel to parallel Universes can be tricky or even dangerous since it is possible to meet yourself and find you have lived a completely different life with different outcomes.
One of those worlds, Earth-X is the name given to an Earth where the Nazi organization won World War II and created a worldwide New Reich called The Fatherland. Due to its horrific state, it doesn’t have a formal designation, since no sane individual from any other Earth has willingly traveled to this Earth.
Harry Wells called it the Earth-53 unofficially. “There’s a 53rd Earth, and it’s called Earth-X. It doesn’t have a designation because it’s a place so awful, so horrific, no sane person would ever travel there.”
As far as DC is concerned, any world which has ever existed in their Universe, including the host of Supermen, Batmen, Wonder Women, and apparently now, Flashes are if your technology is sophisticated enough, and the writers interested in expanding the New DCEU into the older iterations of the DC Multiverse, allowing stories from a host of periods to reintegrate in the modern storytelling worlds.
Strangely enough, the modern DCEU isn’t a single continuum. Barry Allen, the modern Flash, shares a Universe with his Star City’s Green Arrow.
But their world did not have either a Superman or a Batman … though rumors indicate that the character must exist at least in some fashion because Batwoman will be making her appearance in the Arrowverse (the continuity where the Flash and Green Arrow exist – aka Earth-1).
Supergirl exists on an entirely different world where the dial goes up to eleven, because there are two Kryptonians and at least two Martians, powerhouses all, as well as a host of other powerful aliens and even some limited aspects of the Legion of Superheroes. Supergirl lives on Earth-38.
We also know there are other worlds with greater and lesser concentrations of heroes, such as Jay Garrick’s Earth-3 which had far fewer supers and he was the premiere and only Flash of his world. Jay Garrick is a veteran speedster from Earth-3 and the semi-retired vigilante known as The Flash, stylized as the Crimson Comet.
Cisco’s former love interest Gypsy was a law enforcement officer on her own world, policing the banned ability to travel to parallel worlds using the metahuman power of “breaching” between dimensions. Cynthia is an unrivaled collector from Earth-19.
Black Lightning is also considered to live in another continuity where metahumans are being discovered due to a government program which accidentally discovered a mutagen capable of releasing latent superhuman abilities. His world has no current designation in the DC Universe.