Fast-forward to 1940 and a patient in a mental hospital comes upon the lamp and refashions it into a modern train lantern. This act grants him his sanity, allowing him to walk free and reclaim his life. With the second part of the prophecy fulfilled, the lantern ends up on the same train as Alan Scott, ready to complete its third promise -- one of power.
As the train that carries Alan Scott derails from a bridge collapse, the young engineer clings to the mysterious green lantern. Not only is his life saved, but he is granted unbelievable powers that transform him into the Golden Age hero Green Lantern. Except now, in Doomsday Clock #7, Doctor Manhattan makes a subtle change to history.
As the bridge collapses around Alan Scott, Manhattan moves the lantern six inches out of his reach. Unable to grasp the object that grants him his overwhelming gift, the young engineer dies in the accident and the Golden Age Green Lantern is erased from history.
As we read through Manhattan’s narrative, we see history shunted down a different path. Instead of testifying in front of the Joint Congressional Un-American Activities Committee, we hear that Alan Scott's death leaves behind no family. Instead of accompanying Alan Scott into a life of a superherodom, the lantern is recovered from the train wreck and discarded into a scrap heap.
Perhaps most shocking of all, Alan’s death prevents him from becoming a founding member of the Justice Society of America, and as Doctor Manhattan talks of running his fingers through the dust on a familiar round table, the implication is obvious: Without Alan, the Justice Society and the Golden Age of superheroes is also erased.
It has been clear since DC Rebirth #1 that Doctor Manhattan has manipulated the DC Universe in many ways. One of the first examples concerned the original Wally West, who had been lost into the timestream thanks to the powerful Watchmen character’s influence. Now, we can see that his small changes have influenced the universe in ways we cannot fathom. Like a moth beating its wings and causing a hurricane somewhere across the world, Doctor Manhattan's effect is small but devastating.