Flash may have lost one of his most unique abilities thanks to Superman using his famous Cosmic Treadmill to see if he could save Krypton in the past.

Despite their friendship, Superman and Flash have a small rivalry when it comes to who has a more impressive display of speed. While Barry had an edge over Clark for years thanks to his time travel shenanigans, the Man of Steel may have revealed a big secret about the Scarlet Speedster's greatest power.

The question of "Is Superman faster than the Flash?" is one of fandom's oldest questions. And it's a good one since Barry Allen has a number of feats that make a strong case for being the Fastest Man Alive. But Superman's speed is nothing to sneeze at either, and like any other hero, his powers have only become more amazing as time has gone on. Clark may not have a connection to the Speed Force, but his Kryptonian physiology has allowed him to keep up with any member of the Flash Family.

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So what does that mean for a hero who can match the quickness of the Flash? Superman showed that regardless of a connection to the enigmatic Speed Force, a fast-enough hero could utilize the most curious weapon in the Flash's arsenal: the Cosmic Treadmill. In Action Comics #992 by Dan Jurgens, Rob Williams, and Will Conrad, Superman's world begins to unravel when he discovers that his Kryptonian father, Jor-El, is alive and has been posing as the mysterious Mr. Oz. Clark's friends help him realize that someone has been messing with the timeline and that the only way he can figure out what's happening is by seeing Krypton's destruction for himself. He goes to the Justice League's Watchtower and finds the time machine frequently used by the Flash. Putting everything he has into it, Clark activates the Cosmic Treadmill and successfully travels backwards in time.

But, while Clark does succeed in going back in time, it's not the smoothest, or the simplest. But even the Flash doesn't have a perfect record with going back in time, so it's hard to hold that against Superman. Despite the bumpy road he went down, Clark revealed an important detail about time travel in the DC Universe: in order to do it via the Cosmic Treadmill, a hero just needs to be fast enough.

Aside from heroes like Booster Gold or the Legion of Super-Heroes who explicitly have time travel technology, Flash is one of the few characters whose natural power allows him to weave through the timestream. Many fans regard time travel as largely a "Flash" thing for how often his speeds have had drastic effects on reality. But if a Cosmic Treadmill just needs someone to be fast enough, then the door's open for any non-speedster to use it. For example, Shazam has the speed of Mercury. And Mon-El rivals Superman in nearly all his powers. There's plenty of heroes with no connection to the Speed Force that are fast enough to potentially activate the Treadmill. Flash had better keep an eye out on his equipment, because Superman let a major cat out of the bag.

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Justin Epps is either a professional amateur or an amateurish professional depending on who you ask. Wanting to break into entertainment journalism, as well as capitalize on his lifelong hobbies, he's begun taking up writing jobs starting here at Screen Rant. He's currently based in South Carolina and wondering if it's humanly possible to type up 600 articles a month.