How does the Flash phase through walls?

 

The Flash is one of DC’s most iconic heroes. The speedster is a human capable of running at the speed of light and sometimes even exceeding it! Over the years since his debut, the Flash has shown myriad abilities: One of the most famous being his ability to simply walkthrough walls.

To go as fast as he does the Flash draws his powers from a place commonly referred to as the speed force. It is an extradimensional source of power made out of positive tachyons particles that are infused with dark matter and let the Flash access his main ability of super speed and derived abilities like time travel and dimensional breaching

"When the first subatomic particle sprang forth from the Big Bang to form reality as you know it, we were there. When the last proton decays, stops vibrating and plunges the universe into heat death, we'll be there too." This is how a manifestation of the speed force described itself to Barry Allen, the Flash.

One of the major abilities he was granted by the speed force was the ability to go intangible, meaning he could simply walkthrough walls. He does this by using the power of the speed force to vibrate the molecules of his body at a frequency identical to the molecules in the air. This vibration, in effect, simply allows his molecules to move out of the way of other molecules, Letting his phase through walls.

The same ability to vibrate his body gives him several abilities. He can vibrate his throat to distort his voice as a way of disguising it. He can use the vibrations to isolate poisons in his body and phase them out of him. He can use the speed force to increase the vibrations to generate heat to recover and insulate from extreme cold. The Flash can travel between different dimensions by running fast and vibrating at the frequency of a parallel world to open a breach towards that dimension.