The Science Behind The Summer’s Biggest Blockbusters

Man Of Steel

How Strong Can Someone Become?

Inspired By Man Of Steel

THE PLOT: In the latest remake of the 75-year-old comic franchise, Superman, an innocent farmer’s son, discovers his powers and saves the planet from two deranged villains, General Zod and his henchman, Faora, who arrive from Krypton bent on destruction.

THE ANSWER: Superman may be able to lift a bus or an oil platform, but humans come with pretty strict limits on strength, the first of which is the nature of muscle. The maximum force that humans produce depends on how our muscle fibers work. Over the years, scientists have extracted muscles from different vertebrates and tested their capacities. What emerged was a nifty rule of thumb: A muscle can produce about 30 newtons of force (or 6.75 pounds) for every square centimeter in cross-section. “By virtue of evolution being a conservative process, the components of all these muscles are basically the same,” says Peter Weyand, an applied physiologist at Southern Methodist University in Dallas.

So why not just create more muscle? To a degree, humans have been doing that for ages: We’re more physically developed than we were even 500 years ago. But, says Geoffroy Berthelot, a sports analyst, “You can’t increase the mass of your muscle over a certain limit because your bones will not support its strength.” Tendons, while quite sturdy, have limits too—15,000 pounds of pulling per square inch across. Berthelot says that humans may be approaching the upper bounds of athletic performance.

Muscle composition limits human performance as well. Fast-twitch muscle fibers produce more power than their slow-twitch counterparts. With training, athletes may be able to alter their ratio of slow-to-fast, but research suggests it is mostly genetically predetermined.

One way to raise the limit on human strength is to engineer an athlete that is, well, beyond human. A different bone structure could increase the leverage of certain movements. For example, according to Duke University evolutionary anthropologist Steven Churchill, male Neanderthals, when flexing at the elbow, were probably one-third stronger than average men today. So when considering Superman, it’s worth remembering his origin on Krypton. Like a Neanderthal, he is not technically human but humanoid, so different rules apply.

HEALTHY SKEPTICISM: Superman’s suit is just about as indestructible as the man of steel. Comic-book writers have said its strength resulted from a force field or Kryptonian textiles, but that always rang hollow. The only way to make a bulletproof bodysuit would be to reinforce it with graphene, which is flexible, ultrathin, and 50 times stronger than steel.

Pacific Rim

Why Bother Controlling A Robot With Your Mind?

Inspired By Pacific Rim

THE PLOT: When colossal monsters called kaijus emerge from the depths of the Pacific Ocean, humanity tries to fend them off with giant battle bots controlled by pilots linked to neural interfaces.

THE ANSWER: Well, sure. You could use a tried-and-true interface, as drone pilots do. But a brain-controlled interface (BCI) is much cooler. And in principle, it’s better: As any gamer knows, there is a biochemical limit to how fast a brain signal can travel to a muscle, and when battling kaijus, every millisecond counts.

That said, scientists are a ways from that point. BCIs exist—scientists have used them to control robots—but they are pretty clunky. It is difficult to get a clear signal from a brain-wave pattern, which leads to errors and can slow response. “We’re very careful when we talk about BCI,” says Francisco Sepulveda, a bioengineer at England’s University of Essex who worked on neural interfaces for 20 years. “It wouldn’t be a standalone solution except in specific cases.”

Better BCIs, for example, may one day allow quadriplegics to move about or help pilots immobilized by high gravitational forces. But even in those capacities, BCIs could be of limited utility; scientists could more easily create an interface that responds to voice commands or eye movements, or they may not need an interface at all. When it comes to planes or cars (or 2,700-ton robots), autonomous controls are likely a better option.

For those pursuing BCIs, the pilots in Pacific Rim do present a useful idea: They drive their battle bots in pairs, with their brains linked by a “neural bridge.” Sepulveda’s group just finished an experiment on this concept. Participants were divided into teams of two, and software read brain signals from both team members as they tried to run a spacecraft simulator. By merging neural signals, the BCI averaged out some noise and flew with greater accuracy. Turns out two heads are indeed better than one.

** HEALTHY SKEPTICISM:** According to production stills, the kaiju’s_blood runs blue, which is odd but not unheard-of. The horseshoe crab, among other arthropods, has bluish blood. Its blood cells use proteins made from copper instead of iron to carry oxygen. Its blood also clots easily, which allows the crab, and presumably the _kaijus, to recover quickly from wounds.

Star Trek Into Darkness

Will We Ever Swap Perfectly Lethal Guns For Fancy Phaser Pistols?

Inspired By Star Trek Into Darkness

THE PLOT: In the sequel to the 2009 J.J. Abrams film, a terrorist bombing in London triggers a planet-hopping manhunt for a traitorous Federation agent—and a climactic space battle between the turncoat’s vessel and the USS Enterprise.

THE ANSWER: Since it debuted in 1966, the _Star Trek_phaser has remained the stuff of Hollywood prop departments and Trekkie conventions. But directed-energy weapons may be coming to the battlefield soon. Boeing, for example, is developing the truck-mounted 10-kilowatt HEL MD (high-energy laser mobile demonstrator) to defend against swarms of incoming drones, missiles, or mortar rounds. Instead of launching a million-dollar-plus missile for every threat, defense experts could use lasers to destroy multiple targets with precision. Though smoke can dampen a beam’s intensity, lasers don’t have to account for wind speed or range, and they don’t ricochet, limiting any collateral damage.

Boeing is also testing a smaller unit called the Tactical Laser System. While still far from holster-size, it could be mounted on naval vessels alongside an Mk 38 machine gun. The objective would be to defend against drone swarms or a fleet of smaller boats, either by destroying them outright or by using lower-intensity beams to blind or fry sensors (or eyeballs).

Where ray guns become unworkable is on smaller scales. For example, Boeing is working on a portable 2kw laser, capable of destroying unspecified targets (the company won’t go into details). But even this weapon is not small enough to replace the trusty assault rifle; it requires two soldiers to carry it. The laser would be most useful for stealth missions, since it could be set in place and fired remotely, with minimal light and sound.

The greatest challenge in making handheld directed-energy weapons is the energy itself. A 100kw laser can consume two cups of diesel in a four-second engagement. That’s a bargain compared to launching missiles. But a general-purpose, infantry-scale death ray would require fuel with an energy density that today’s researchers can only dream of. “We’re not close,” says Suveen Mathaudhu, a materials engineer in the U.S. Army Research Office. To create that, he says, “would require a major, major breakthrough, on the level of fusion technology.”

HEALTHY SKEPTICISM: At one point in the film, Spock attempts to extinguish a volcano with something like a super ice cube. To quench an eruption, though, you’d need to solidify the magma all at once, says Erik Klemetti, a vulcanologist at Denison University. That would require instant cooling on a massive scale; anything less would only create lots of steam, which would just intensify the eruption.

Iron Man 3

Will Exoskeletons Ever Fly?

Inspired By Iron Man 3

THE PLOT: Rakish billionaire, inventor, and superhero Tony Stark faces a series of attacks—including an air strike on his home and wrestling matches with nanotech-enhanced goons—launched by an international terrorist who calls himself the Mandarin.

THE ANSWER: In Iron Man, Tony Stark’s suit is incredibly powerful, a wearable weapon system that can hurl cars and outmaneuver jet fighters. In reality, it is the synthesis of two technologies: the jetpack and the exoskeleton, which is the more promising of the two. In terms of exoskeletons, no one will be bench-pressing Buicks anytime soon, but a number of systems already exist as assistive or rehabilitative medical devices. Companies such as Argo Medical Technologies and Ekso Bionics offer motorized devices targeted to the disabled that can essentially walk for their wearers, allowing users a more versatile alternative to wheelchairs. There could be other applications for exoskeletons, too. At NASA, researchers are working to incorporate them into space suits. They have developed one that could eventually allow astronauts to hike across Mars for long stretches, loaded with gear, while expending little energy.

Meanwhile, the development of rocket belts (the technical term for jetpacks) is at a relative standstill. A handful of models have debuted in the past decade—including Jet Pack International’s H202 and TAM’s Rocket Belt—but none have amounted to more than a PR stunt. The systems struggle to stay aloft for a useful amount of time, emptying fuel tanks in less than a minute. The additional weight of an exoskeleton would only exacerbate the problem.

As for the future of exoskeletons, NASA engineer Chris Beck says that today’s systems, such as the X1 that he’s developing, will lead to the superhuman systems of tomorrow. “We’re not just blowing smoke. An exo like ours, or an adapted version, could be used for strength augmentation,” he says. Exoskeletons might also fly—just not with jetpacks. “What if you combined ultralight planes and our auto-balancing techniques?” says Larry Jasinski, CEO of Argo, whose ReWalk exo is for sale for personal use in Europe and Israel. Instead of a pilot’s seat and a traditional control layout, the flier might simply squeeze into the aircraft’s integrated suit. “You could literally lean left or right, and the exoskeleton components could steer for you.”

HEALTHY SKEPTICISM: Iron Man’s jet boots work underwater, which ignores the fact that combustion-based jets drown when submerged. DARPA sought proposals for submersible aircraft in 2008, but that project, it seems, is dead in the water.

Elysium

Can Humans Survive On A Permanent Orbital Colony?

Inspired By Elysium

THE PLOT: In 2154, the wealthiest humans live on a posh orbital station called Elysium. One man tries to harness the upper crust’s lifesaving technology to save the poor, disease-ridden masses still on Earth—starting with himself.

THE ANSWER: Spectacular views notwithstanding, living in space is hard. Microgravity drains the mass from our flesh and bones, and the radiation normally blocked by Earth’s magnetosphere can shorten lifespans. So the premise of Elysium presents a conundrum: Why would the planet’s most pampered occupants pay to live in orbital habitats that turn them brittle and cancerous?

In the film, the answer is that money cures everything. The station’s health care exceeds anything on Earth, with devices that erase nearly all physical ailments, including cancer. As for the hazards associated with low gravity, Elysium is a Stanford torus, a design first proposed in the 1970s, where inhabitants live on the interior of a gigantic, rotating wheel, with centrifugal force providing Earth-equivalent G-forces.

In theory, the torus is scientifically sound, but building it might be impossible. It would require hauling millions of tons of material into orbit. “It might literally be easier to colonize the moon than to construct this Stanford torus,” says John B. Charles, chief of human-research programs at NASA. It could also be difficult to innovate away the health threats associated with living at the edge of Earth’s magnetosphere. Present-day astronauts can absorb two to three years’ worth of radiation aboard the International Space Station, in multiple stays, before being grounded. According to Charles, a more permanent habitat would most likely use available materials such as wastewater to deflect radiation. In the end, it would take a lot of work just to avoid wasting away. Hope that view is worth it.

HEALTHY SKEPTICISM: Matt Damon’s rifle-size railgun should raise some eyebrows. The benefit of supplying some 100,000 amperes per electromagnetically propelled shot is a longer range. That might make sense for a ship-mounted weapon, like the one the U.S. Navy is conceiving. For gunfights that don’t span miles, though, gunpowder is more practical.

This article originally appeared in the July 2013 issue of Popular Science. See the rest of the magazine here.