A particle collider, engineered with a 4th dimensional component, the Flux Capacitor makes time travel possible by creating, containing, and releasing a concentration of tachyon particles which, when properly focused, create a wormhole and open a portal through the time continuum.

“Yes! Of course! November 5, 1955! That was the day I invented time-travel. I remember it vividly. I was standing on the edge of my toilet hanging a clock, the porcelain was wet, I slipped, hit my head on the sink, and when I came to I had a revelation! A vision! A picture in my head! A picture of this! This is what makes time travel possible: THE FLUX CAPACITOR!” – Doc Brown