Based in the works of Howard Chaykin's Twilight and Thrillkiller series. A world were the technology accelerated in the 60s (the time when Batgirl lived in Gotham) and space conquest was faster, making possible the space travel in the 80 and in the 90s were already space colonies in the jovian moon Europa. Twenty years later, the interstellar exploration is a reality lead by Tommy Tomorrow and acompanied by Manhunter 2015 and the Space Ranger.
Technology develops in fits and starts. Slow periods of theorizing and experimenting are often followed by concentrated bursts of breakthroughs. That pacing gives humanity time to breathe and adjust to the latest advancements. But it is possible for technology to progress at an accelerated rate, as it did on Earth-37—for better or worse.
The momentum of discovery propelled this world through the latter half of the 20th Century. In the span of a mere three decades, the inhabitants of Earth-37 went from terra firma to the stars, from living in suburbia to residing in underground colonies on Mars, from the ordinary to the extraordinary. Heroes such as Tommy Tomorrow, Manhunter 2015, and the Space Rangers have the led way to interstellar colonization.
But despite the list of incredible achievements, Earth-37 is not a home to idealists. This is a place of reckless heroes who skirt the law and follow their own codes. Champions here don't fight with hope in their hearts, but with cynicism in their souls.