The science of superheroes: What would human flight be like?

Traffic woes alone make flight a preferred superpower. But how would the human body handle it?

Published April 15, 2018 2:00PM (EDT)

Robert Downey Jr. as Tony Stark/Iron Man (Marvel Studios)
Robert Downey Jr. as Tony Stark/Iron Man (Marvel Studios)

In the year of glass-ceiling shattering releases like "Jessica Jones" and the subversion of Hollywood norms in the production of "Black Panther," 2018 also brings with it the release of another “new” type of superhero story — the story of the science behind these extraordinary powers.

"The human bird shall take his first flight, filling the world with amazement, all writings with his fame, and bringing eternal glory to the nest whence he sprang.” —Leonardo da Vinci, Codex on the Flight of Birds (1505)

“For once you have tasted flight you will forever walk the Earth with your eyes turned skyward, for there you have been, and there you will always long to return.” —Leonardo da Vinci, Codex on the Flight of Birds (1505)

“All in all, for someone who was immersed in, fascinated by, and dedicated to flight, I was disappointed by the wrinkle in history that had brought me along one generation late. I had missed all the great times and adventures in flight.” —Neil Armstrong, Neil Armstrong: Quotes and Facts (2015)

Modern daily life can be a drag. Sure, science and tech have brought us the wheel, New York, the smartphone, etc. But dwell on the drawbacks a little: spam emails, self-serve tills, and predictive text, to name but three. Then there’s snail’s-pace wifi, being a sociopath on social media, and dealing with trolls on Twitter.

But worst of all is the terrible traffic. There can be no greater need for the dream of human flight than today’s jam-packed world of traffic. Take China, for example. September 2013 saw the world’s longest traffic jam, more than 100 kilometers long and lasting for weeks. The problem is so common in China that some folk have embraced it as an entrepreneurial opportunity. Their motorbike businesses will weave their way between the gridlocked lanes and take you to your destination. Hell, they’ll even provide someone to sit in your car for you until the jam is done, if it ever ends. Pizza deliveries to jammed cars are also very common. Pizza express, even if the traffic isn’t.

Little wonder flight is so popular among entrepreneurs. In 2015, American business magazine Forbes found that flight was the business leaders’ superpower of choice. Collecting data from professional leaders who read their blogs, Forbes posed the question, “If you were given a choice of two special powers, which would you prefer? A. Ability to fly, or B. Power to be invisible.”

Flight came first in all classes. Forbes gathered data from 7,065 leaders around the globe: 63 percent of the data from North America, 13 percent from Europe, 16 percent from Asia, with 8 percent from all other respond­ing territories. Clocking up superiority over invisibility of almost three to one, 72 percent of business leaders chose the ability to fly over being invisible. Data analysis of the corporate positions of responders found that 76 percent of top managers selected the ability to fly, as compared to only 71 percent of individual contributors. The idea of human flight is pretty popular.

But if humans did know natural flight, just how fast would we fly? The first human to break the speed of sound, mostly without using tools or tech, was Austrian skydiver Felix Baumgartner. This daredevil and BASE jumper reached a maximum velocity of 833.9 mph (1,342 km/h) on October 14, 2012. Felix launched himself out of a balloon at 128,100 feet (that’s 24 miles or 39 kilometers) above New Mexico.

Felix almost failed the dive, as his helmet visor fogged up. His twenty-four-mile flight took just under ten minutes, with the last few thousand feet of the descent done by parachute. Felix was quoted by the BBC after the flight as saying, “Let me tell you—when I was standing there on top of the world, you become so humble. You don’t think about breaking records anymore, you don’t think about gaining scientific data—the only thing that you want is to come back alive.”

But Felix’s feat wasn’t flight, it was freefall. Now, consider footspeed. Whereas forty-three-year-old Felix smashed the record for the highest ever freefall, twenty-two-year-old Usain Bolt broke the footspeed record. Footspeed, also known as sprint speed, is the maximum speed at which a human can run. Bolt’s record was recorded at 27.8 mph (44.72 km/h) during the 100-meter sprint final of the World Championships in Berlin on August 16, 2009, five days before Bolt’s twenty-third birthday. The average speed Bolt clocked over the course of the race was 23.35 mph or (37.58 km/h). But Bolt owes his footspeed to Newton. Usain’s sprint speed depends on how much force is brought to bear by Bolt’s formidable legs, and according to Newton’s Second Law of Motion, that force is the product of mass and acceleration. Newton’s Third Law says that for every action, there is an equal and opposite reaction. In the case of the mechanics of footspeed, this translates into Bolt’s running action needing a firm ground to push against, with the ground effectively pushing back against Bolt.

Moving Swiftly Through Water and Air

Flight is far more similar to swimming. You’ve no doubt seen the frantic freestyle swimmers stroking swiftly through their lanes at the Olympic Games, but are those competitors really chopping through the water like sharks? Nope. Truth is, those guys are hardly moving. The fastest recorded human swim speed is less than five miles an hour. Hell, a toddler torpe­doed by a self-inflicted tantrum can outrun those Olympic swimmers.

And the reason why goes back once more to Newton. As Bolt runs, he speeds along because his legs push against the track with his feet and the track pushes back, thrusting him forward. Athletic tracks are solid. And that means the particles in the track are basically bonded together and must push back against Bolt, rather than simply moving out of the way. The same goes even for the torpedoed toddler: firm ground. But the Olympic swimmers have another medium to mess with. Water is fluid and flows far more easily. When those Olympic leviathans plunge their limbs to push back against the water, some of the water molecules are easily able to slip past one another rather than pushing back against the swimmer’s limbs.

Now, think about applying our swimming lesson to the question of flight. Air, like water, is also a fluid, but the gas particles that make up air are far freer to move about than the liquid molecules of water. As gases are less dense than liquids, air has more free space for particles to slip and slide past one another, so a human flyer would waste more energy than a human swimmer because a lot more air would have to be pushed backward to be able to move forward.

Consider Sandra Bullock as Dr. Ryan Stone in the 2013 movie, "Gravity." Stone is an astronaut stranded in space after the mid-orbit destruction of her space shuttle, and is trying against all odds to return to planet Earth. In some scenes we see Stone moving around a spacecraft in microgravity. How does she do it? She doesn’t waste time flapping around in the near vacuum of space. She simply pulls on handles installed on the ceiling, walls, and floors of the craft to get purchase and make headway.

Imagine, like Stone, you were able to float. Not in the microgravity medium of space, but down here on good old Earth. Exactly how would you get purchase to move about from block to block in the middle of the street? You couldn’t do a Spiderman and swing from a web. And swimming through the air wouldn’t get you very far either, but let’s assume we make less fuss of this physics and grant you the fishy ability to float. Maybe some kind of antigravity thing is going on. Yeah, that’s it. And let’s also assume you are free to speed about using some kind of thruster tech previously unknown to man.

Straighten Up and Fly Right

How high would you be able to go? Remember that scene when Iron Man zooms up through the lower atmosphere, taking his suit on its first flight, and he finds it has a problem with freezing at high altitudes? Well, there’s an area of physics around the behavior of gases, and it’s known as thermodynamics. One of the laws of thermodynamics, the Ideal Gas Law, says that the pressure and temperature of a gas increase and decrease together. Written down in an equation, the Ideal Gas Law looks like this: PV=nRT, where P is the pressure of the gas, V is its volume, and T its temperature. N is the quantity of gas molecules in moles, and R is the ideal gas constant, 8.314 J/Kmol.

As you fly up into the atmosphere, there is less pressure. Air expands in volume with less pressure, so the molecules have more room to wander around without colliding into each other and creating heat. And as the pressure is a lot lower at high altitudes, it would be freezing cold if you were flying above the clouds, so you would need to keep your core body temperature warm or you’d soon begin to shiver violently, become men­tally muddled, and plummet out of the sky due to lack of muscle control from hypothermia.

Volume would be a problem, too. The Idea Gas Law shows that as pressure decreases, gas volume increases, so if you were to fly straight up too quickly, the gas inside your body would expand rapidly. It’s like when soda fizzes up when jiggled. The name for this is decompression sickness, which is perhaps better known as “the bends,” and it’s the phenomenon associated with the experience deep-sea divers get when they come up too quickly. It’s been known since 1670, when Irish chemist, Robert Boyle, experimenting with a viper in a vacuum, showed that a reduction in ambient pressure could lead to the formation of a bubble in living tissue. In humans too, the bends results in pain, paralysis, or death, based on how foamy your blood becomes.

So, let’s say we stray away from flying too high. If we keep our flight paths a little closer to the ground, what then? On the plus side, we’ll be able to see all the road furniture, mostly meant for regular traffic. There’s also the added advantage of being able to breathe oxygen with ease! Best copy winged superhero, Falcon, though, and goggle up. You’ll probably need a helmet like Captain America, too, for protection against electrical cables, insects, birds, and high-hanging street signs.

On the more dangerous side, there are the drones. Sure, there are also other flying humans, including flying cops ready at the drop of a wing to gift you a ticket for jay-flying in the wrong intersection of air or something, but that’s nothing compared to the coming threat of drones. No doubt some day in the future NASA and others will have finally nailed drone traffic management. But until that day, beware of the drones.

For the skies are getting crowded. The Federal Aviation Administration (FAA) of the United States and its European counterpart the EASA report that the number of near-misses with drones has surged since 2014. There were as many as 650 cases as of August 2016. Dubai airport has been repeatedly shut down by drone activity, and in July 2017 a pilot reported to the Australian Transport Safety Bureau that his light aircraft was struck by a drone ahead of landing in Adelaide. In time, these drone mechanical birds may potentially grow bigger and more dangerous.

But maybe Leonardo da Vinci is right. Once you’ve tasted flight, you will always long to return skyward. Sure, you may have a drone collision in mid-air which knocks you senseless so you find yourself in free fall, just like Felix Baumgartner. But, ignoring aviation authorities and some of the laws of physics, most potential flyers would opt for flight, as they gaze down at the miles-long traffic jams below.

Excerpted with permission from "The Science of Superheroes: The Secrets Behind Speed, Strength, Flight, Evolution and More" by Mark Brake. Copyright 2018 by Racehorse Publishing, an imprint of Skyhorse Publishing, Inc. Available for purchase on Amazon, Barnes & Noble, and Indiebound.

By Mark Brake

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