First Appearance: Flash (first series) #125 (December 1961)
After super-speed vibrations accidentally sent Flash Barry Allen into the distant past, he decided to investigate controlled time travel. Over the course of a few weeks he developed a treadmill powered by cosmic rays. When he ran at top speed, the treadmill would trigger specific vibrations that would launch him forward or backward in time. He would stay in that time period by maintaining that internal vibration, and return to his own time by relaxing it. The treadmill’s controls were calibrated* so that he could set it for a particular era and it would produce the exact vibrations he needed to get there.
(In the pre-Crisis DCU, the Cosmic Treadmill also enabled the Flash to travel to parallel universes more reliably than he could on his own.)
Since it depended on a speedster’s control of his own molecules, the treadmill was only an expensive curiosity to the general public, and after Barry’s death it became an exhibit at Central City’s Flash Museum. This did turn out to be a problem, however, as future speedsters—most notoriously Professor Zoom, the Reverse-Flash—were able to break into the museum and use it to travel into the past. One wonders why it was not moved to the more heavily-guarded Time Institute in the 27th Century.
While the third Flash, Wally West used the treadmill occasionally as Barry’s sidekick, he only rarely used it during his solo career. Part of this is due to having temporarily had a lower top speed, part of it is due to an aversion to time travel stemming from an as-yet undisclosed traumatic experience when he was younger...and part of it is due to his discovery that, because of his direct connection to the Speed Force, he can travel through time on his own.
Barry eventually determined that it was possible for speedsters to travel through time without the treadmill, but very imprecisely. One could try to jump forward a few decades, only to find that several millennia had passed. So far, only Wally West has been able to time-travel precisely under his own power.
When 27th-Century Flash John Fox relocated to Wally’s era, he upgraded the treadmill using his own time-travel technology, “to make it work more as a straight time machine.” Oddly, the cosmic treadmill appears to have since reverted to its original state. Perhaps the timestream adjusted itself to cover up a paradox, or perhaps he simply removed his modifications before he left and rebuilt his own time gauntlets.Text by Kelson Vibber. Do not copy without permission.
- Classic: Flash (first series) #125 (December 1961) - Carmine Infantino & Joe Giella
- Upgraded: Flash (second series) #112 (April 1996) - Anthony Castrillo & Hanibal Rodriguez
- Silver Age Secret Files #1 (July 2000)
- Flash Secret Files and Origins 2010 (May 2010)
- Flash #125 (December 1961): “The Conquerors of Time,” John Broome
- Flash #139 (September 1963): “Menace of the Reverse-Flash!” John Broome
- Flash #146 (August 1964): “Fatal Fingers of the Flash!” Gardner Fox
- Flash #147 (September 1964): “Our Enemy, the Flash!” John Broome
- Flash #153 (June 1965): “The Mightiest Punch of All Time!” John Broome
- Flash #162 (June 1966): “Who Haunts the Corridor of Chills?” Gardner Fox
- Flash #179 (May 1968): “The Flash—Fact or Fiction?” Cary Bates
- Flash #186 (March 1969): “Time Times Three Equals—?” Mike Friedrich
- Flash #198 (June 1970): “Call It...Magic,” Mike Friedrich
- Flash #203 (February 1971): “The Flash’s Wife is a Two-Timer!” Robert Kanigher
- Flash #204 (March 1971): “The Great Secret Identity Exposé!” Robert Kanigher
- Flash #210 (November 1971): “An Earth Divided,” Cary Bates
- Flash #236 (September 1975): “Nowhere on the Face of Earth!” Cary Bates
- Flash #237 (November 1975): “The 1,000-Year Separation!” Cary Bates
- Flash #260 (April 1978): “The 1000 Year-Old Root!” Cary Bates
- Flash #263 (July 1978): “Nobody Stays a Flash Forever!” Cary Bates
- Flash #269 (January 1979): “Domain of the Dark-Eyed Dragons!” Cary Bates
- Flash #282 (February 1980): “Mishmash!” Cary Bates
- Flash #350 (October 1985): “Flash Flees,” Cary Bates
- Flash 50th Anniversary Special (1990), Mark Waid
- Flash #79 (August 1993): “The Once and Future Flash” (Return of Barry Allen conclusion), Mark Waid
- Flash #112 (April 1996): “Future Perfect,” Mark Waid
- Legionnaires Annual 3 (1996): “The Long Road Home,” Roger Stern
- Impulse #25 (May 1997): “You and Me Against the World,” Mark Waid
- Flash #145–150 (February–July 1999): “Chain Lightning,” Mark Waid and Brian Augustyn
- Flash: Time Flies (2002), John Rozum
- Flash #196 (May 2003): “Helpless,” Geoff Johns
- DC Comics Presents: The Flash (October 2004): “Flash Back!” Dennis O’Neil
- Teen Titans (third series) #19 (February 2005): “Titans Tomorrow Part 3: East Meets West,” Geoff Johns
* The Cosmic Treadmill was calibrated in Roemers, where one Roemer is the speed of light, much as Mach 1 is the speed of sound. The unit was named after the Danish astronomer Ole Rømer, who first measured the speed of light, as Mach numbers are named after Ernst Mach. To the best of my knowledge, the Roemer unit was invented for the comic book. (Thanks to Dave Kyle for pointing this out.)