The flux capacitor is a fictional device from the “Back to the Future” movie franchise that is said to make time travel possible by generating the 1.21 gigawatts of power needed to activate the time machine. It is described as a “high-voltage, multi-layered capacitor” that is “what makes time travel possible” according to the character Doc Brown.

In the movie, the flux capacitor is shown as a cylindrical device that is installed in the DeLorean time machine. The device is charged with electrical energy from the car’s nuclear reactor and generates a powerful magnetic field that allows the time machine to travel through time.

It’s important to note that the flux capacitor is purely fictional and not based on any real-world science or technology. The concept was created for the “Back to the Future” movies as a plot device to enable time travel in a fun and exciting way.