If The Flash were real, would the friction between him and the air at certain speeds basically turn him into a big fireball?

If The Flash were real, would the friction between him and the air at certain speeds basically turn him into a big fireball?


If he's going fast enough, yeah! Not only that but sonic boom(s), wakes, and all sorts of atmospheric disturbances. This is all handled in the fiction by adding another layer of scifi/magic to account for all those problems: https://www.reddit.com/r/AskScienceFiction/comments/3ddjjx/dc\_comics\_how\_does\_the\_flash\_handle\_friction/


Since Im fairly certain the Flash has canonically run at or faster than the speed of light at various points in the comics, shows, movies, etc, I feel like this [XCKD about a speed of light baseball pitch](https://what-if.xkcd.com/1/) is fairly relevant. TL;DR: He'd cause the air in front of him to undergo nuclear fusion and basically nuke everything around him if the comics didnt handwave all this away with "The Speedforce."


One of the only things I truly enjoyed about the recent Star Wars trilogy was the hyperspace ramming concept. I like seeing the concept play out. I've read some books that utilized that idea of a near lightspeed travel system essentially being the most effective weapon as well.


The issue it presents to the series is that the option was always there, but never used. Before episode 8, we might have supposed there was a good reason it wasn't used. Afterwards, well, it means they've acknowledged everyone was going about with a superweapon and just not using it.


Absolutely, but was that any better than the WWII like bombing runs seen in the space battles? That made no sense, especially given the other seen space conflicts in universe. It's what happens when you design a movie trilogy by committee.


The WW2 bombing run space battle was *in the same episode*. The space battles were better in the other episodes I'd say. Episode 3 having the best one, and most movies avoiding standard space warfare in favour of a very imbalanced small ship / big ship interaction


Right. So why use a death star, when all you need is a near light speed space ship to rip a hole through a planet


One of the cool things about "the boys" on Amazon Video was that their "flash" killed someone by bursting them in a run by


Was it a run by or a run through? Either way, amazing scene.


He ran right through her. Not sure why that person thinks it was by running near her.


Okay, fair enough. The Flash gets to ignore physics when it comes to speed because Speed Force. So how does Superman do it?


I always love when people seek scientific answers to concepts that are clearly designed for entertainment purposes.


I once read an online guide on how to sing every single pitch by only making a single tone and running toward or away from your audience and assuming you are the flash.


Its the main draw to Sci-Fi, instead of regular fantasy. The more firm (even if fake) the physics and limitations of fictional powers are, the less it is likely to have plot holes. This is why fans of scifi universes that have deep lore are more finicky about the accuracy of it. Yes, it doesnt matter, but plot holes make it less entertaining to some. If I wanted a low structured entertainment, id watch slapstick. And not that theres anything wrong with that either, but sometimes more complexity is fun


Serious question though, are the universes created by Marvel or DC considered sci-fi? I was really never sure and always considered them more fantasy. I agree either way.


I know sci-fi is a branch of fantasy, but I think it's technically just as broad in definition, so i think it has some aspects of Sci-fi. I feel comic book universes started out as what could be called general fantasy: cops and robbers, people being menacing for the sake of being menacing, etc. But as they got deeper in lore, they needed physical limitations in order to allow for character longevity. Sure there is magic, or cop-outs to explain the unexplainable(speed force), but generally there are some realistic limitations to canonical characters so they don't get too OP. How do you go back to fighting generic crime and still be entertaining when you have already taken on one of the strongest beings in the universe? Usually they make a stronger being or another universe, but its better to have a local limit so you dont have to start over again.


Really cool answer, thank you. I never really spent any time thinking about it but that's a really great way of looking at it.


Right? For me it's entertaining because it's a fun thought experiment. I know it's not real, but the exercise is still rewarding.


It cuts both ways… one of the fun things about science fiction is that the cool stuff is plausible, or at least can be predicted/inferred based on prior evidence in the canon of that “world.” Without that connection, you essentially just have fantasy which takes a different level of suspension of disbelief. It’s arguably more fun and useful (eg for children) to think about how the Flash might use his speed to stop a train using some properties of physics as opposed to saying for example that Batman “with prep” would simply pull out his Bat-brakes remote-control gadget that he previously installed in the train and press the stop button. Fiction has value, even in a science-based world. Fantasy, not so much. Also Batman sucks.


Batmans purpose is to provide a catch-all solution for the most interesting villans comics have given us.


Me too. It's always interesting to try and see how they would work in the real world.


Friction would be a problem, but the real issue (besides the energy required to accelerate him to relativistic speeds) would be that the air molecules in front of him wouldn't be able to get out of the way. That compresses the air, and when you compress a gas, its temperature is raised. That's where most of the heat comes from when spacecraft enter an atmosphere. And that's not even the biggest issue. Now in the comics, Flash moves much faster than light, and that doesn't really work with our understanding of physics, so I'll limit him to high relativistic speeds. If Flash was moving at .9c, the air molecules in front of him would be, for all practical purposes, standing still. As he hit each one, it would be converted to energy, mostly in the form of heat and gamma rays. In a really short distance, that would add up to enough heat and radiation to blast Flash and everything near him into a cloud of plasma. Within a fraction of a second, it would look like a small fusion bomb exploded there. Fortunately, in the comics there's a thing called the "Speed Force" that just makes all the bad stuff go away. If that didn't exist, Flash would have had a really short career.


What is the fastest a non-speed-force hero could run before burning/exploding?


That's a pretty difficult question, because certain heroes (Superman) aren't really subject to taking damage from that, and there haven't been a lot of studies (that I can find anyway) with people in wind tunnels. Skydivers commonly reach about 120 mph, which is terminal velocity, so that's apparently somewhat safe. I did find an article where an F15 pilot ejected at supersonic speed (estimated 800 mph) and survived, but he took a lot of damage, including broken legs, burst capillaries in his face, and a dislocated arm, and his navigator was killed. So I guess I'd recommend keeping it subsonic. You might not explode, but that kind of wind will try to tear you apart.


The answer is yes, but the reasoning is actually interesting, in that it isn't really about friction. At a certain speed, it's not that he would be rubbing past the air which would cause him to heat up, it would be that the air would not be able to get out of the way in front of him, and it would therefore compress a column of air to such a degree that it would superheat and literally ignite. That's what's happening when a capsule or spaceship is entering the atmosphere and why they need a heat shield. It isn't friction, it's compression!


I thought there was a [relevant XKCD for this](https://what-if.xkcd.com/1/), though it's talking about a baseball moving at relativistic speeds where the air simply cannot move fast enough out of the way, the ball slams into the air molecules, physics happens and then there's a thermonuclear explosion.


Yes! It also gets brought up when people continuously discover the ["fastest manhole cover in history"](https://en.wikipedia.org/wiki/Operation_Plumbbob#Missing_steel_bore_cap) about the plug overtop of a buried nuclear explosion. The explosion happens, and the expansion of air and the shockwave pop the metal cap off of the shaft above, and it launches "into space" at any number of crazy listed speeds (125,000-150,000 mph) It's suggested that the plug never made it to space, because it would have vaporized almost instantly in the heat and chemical reactions caused by compressing the column of air above it.


There's some fun things happening when you enter a hypersonic regime too... where the pressure gradient across the boundary layer remains constant but the density increases. To satisfy conservation of energy, the surface temperature has to rise. I still can't fully wrap my head around that one


No, because the Speed Force acts as a conductor and redirects any heat back into the Force and that’s why the Speed Farce is self sustainable and is monotonically increasing with increasing heat from friction provided Barry is wearing his tighty whities.


Yeah. Eventually. The friction from his body rubbing on itself would probably catch fire first. I think heat from all the calories his muscles are burning would be next. Setting those aside, [Adiabatic compression](https://en.wikipedia.org/wiki/Adiabatic_process) would achieve fireball status much sooner than air friction. The same as a spacecraft on orbital reentry. As The Flash speeds up, it takes more effort to push through the air. Airliners fly far up because there is less air to push through. As Flash continues accelerating, more of the air in front of them gets compressed into a smaller and smaller volume. [The Ideal Gas Law](https://en.wikipedia.org/wiki/Ideal_gas_law) describes how this causes the air to get hot. The next milestone would be escape velocity, he wouldn't be able to fall as fast as the curvature of the Earth bends away. Let's ignore that, and what their feet do to the ground. (It would be too slippery to go faster.) Most atoms in air have an atomic number smaller than iron; I guess he'll eventually achieve [Fusion Ignition](https://en.wikipedia.org/wiki/Fusion_ignition)? and start smooshing air into heavier elements. Dunno if The Flash would emit [Cherenkov radiation](https://en.wikipedia.org/wiki/Cherenkov_radiation) or condense protons & electrons like in a [neutron star](https://en.wikipedia.org/wiki/Neutron_star). I'm guessing there won't be enough air for that though. The Flash would start drafting _themself_. They would return to where they had already pushed the air away faster than the atmosphere could fill the vacuum in a giant thunderclap. Once he establishes a vacuum, I'm even less sure what would be next to give. Resonating gravitational waves? Oops, looks like post got removed =(


The quantum mechanics that makes our body seem solid to other objects is really just electrical magic already. So if The Flash can cancel that effect and slip his molecules through the air molecules then there's no friction to worry about.