Not only is he the fastest man alive, but thanks to the CW and its upcoming fall lineup, he's also one of the most talked about comic book heroes in modern times. If you hadn't guessed it already, we're talking about Barry Allen aka "The Flash." As you probably surmised already, the show will focus on the wacky (and admittedly heartbreaking, at times) journey of an awkward teen who develops superhuman abilities. As far as powers go, this guy is pretty popular, and why wouldn't it be?
At some point in our lives, we've all pretended that we can run very fast and/or defy gravity. However, some of that childhood magic was lost when we started learning about a little thing called "physics," and with that, we understand how the world works (and away went or dreams of walking in the clouds). Spoiler alert: The real world is a lot different from a comic book, but does that take all the enjoyment out these 'unbelievable' stories? Well, no. Obviously not, or we wouldn't be here right now, would we?
With that said, one of the most interesting bits about comic books is trying to figure out how these purported superpowers would work in real life. Questions like this pose a bit of a conundrum for science-minded people, as comic book writers often do not care about the physical implications of said powers. I mean, who cares if nothing can move faster than the speed of light if superman needs to do so in order to turn back time and save the world from destruction? Who cares that, even if he could travel at light-speed, he would utterly annihilate anything/anyone that he punches with that superpowered arm?
Bearing all this in mind: To analyze The Flash, we need to make a couple of assumptions:
- First, The Flash's body can exert the force necessary to move very fast, and his body can withstand forces of this magnitude.
- Second, The Flash's brain can sense things very fast, ergo he can think on his feet (get it?) and can process external stimuli just as quickly as he can move.
Now then, if something is moving through the air at some velocity, it experiences a drag force due to air resistance. The drag force increases exponentially with velocity. To run faster, The Flash's body needs to exert an exponentially increasing force to the ground. When we run at normal speeds, this drag force is small to the point that we don't feel it at all.
Another implication of moving very fast is the friction that our movements produce. Friction, in turn, produces heat, so the Flash's body (and his spandex/latex costume) would have to be VERY resistant to sweltering heat. A "proof of concept" for this is when a meteor strikes the Earth. We all know that meteors burn up rather quickly once entering our atmosphere. This is because they are traveling very fast, and they are faced with extremely high temperatures as a result of the friction caused by entering our atmosphere (in short, our air rubs up against them). Most of them do not survive; however, shuttles can. This is because they have heat-resistant shields (other materials used to build them help too). SO, assuming Flash's body can withstand this heat, his costume should be made of a very heat-resistant material to prevent the latex costume from melting and going where no latex has ever gone before (hopefully).
Now that we've got that uncomfortable theoretical out of the way, let's discuss the logistics of his job. The Flash usually uses his power to save people from danger by carrying them to a safer place, but in reality, Flash can never do this. To be able to carry people and move at a very fast speed, you need to accelerate, and there is a limit to the acceleration that the human body can withstand (this also poses a danger to all warp-speed engine designs). This is because our body is not entirely solid. Our brain would be smashed into our skull and our inward fluids would condense to the direction opposite of our direction of motion. Interestingly, the script writers of "X-Men: The Days of Future Past," somehow took this into consideration. Quicksilver held Erik's (Magneto) head before they escaped from prison, saying that it was to protect his head from snapping back and being broken.
The most important implication, of being able to move very fast, is that The Flash would literally be the strongest superhero of them all. Moving very fast requires heightened acceleration, which in turn, requires a larger force. Consequently, he would be very deadly in battle. A fast punch from The Flash would pack a lot of momentum, and thus, on contact, he would exert a very large force (in short, more force = more power).
For me, being able to understand how these things might work with a real basis in physics only makes these stories more fascinating. Moreover, superhero stories can be a great way to spark our interest in learning more about how our world operates and the physics behind it.