Science turns out to be just as effective as Kryptonite at bringing superheroes crashing to earth. Deconstructing the logistics of superpowers is as dear to nerd culture as nitpicking at plot holes, and it's all the more devastating if the overanalytical geek happens to have a PhD.

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Take Batman: In December, British physicists calculated that in the real world, his daring leaps off of the tops of buildings would turn him into Bat-road pizza.

In a paper titled Trajectory of a falling Batman, four University of Leicester physics grad students examined the imaginary apparatus that the Caped Crusader uses in the film 'Batman Begins,' a cape made of 'memory cloth' that stiffens when electrified.

The students found that while Batman's cape would allow him to glide from the top of a building 150 meters (nearly 500 feet) tall, he would have a lot of trouble sticking the landing, as he'd be approaching the ground at around 50 miles an hour.

At these high speeds, any impact would likely be fatal, if not severely damaging (consider impact with a car travelling at these speeds), the students wrote.

For a less fatal dive, Batman should be packing a Bat-Parachute in his utility belt, they advised.

Dangerous Superpowers

One of the earliest artifacts of overanalytical nerd arcana is the 1971 essay Man of Steel, Woman of Kleenex from science fiction author Larry Niven, which outlines the potential complications Superman would face if he attempted to reproduce with a human woman.

Aside from the danger that Superman would accidentally crush a human woman while in the throes of passion, Niven said the act would probably conclude with the superhero's powerful climax blasting through his unlikely partner's head. (This idea was used in a discarded scene in the 2008 movie Hancock, when Will Smith's superhero character tosses a woman to the side mid-coitus before blasting holes in the roof of his trailer.)

If Superman went the artificial insemination route, Niven thought, any super-sperm that didn't reach an egg could still be powerful enough to burrow out of his partner's body and fly through the sky, seeking out random women and resulting in thousands of unintended super-pregnancies.

Several thousand lawsuits would follow. Not that Superman can't afford to pay. There's a trick where you squeeze a lump of coal into its allotropic diamond form, Niven wrote. (Though some would argue it's not exactly that simple -- if you tried to press an ordinary lump of coal into a diamond, you'd end up with a gem chock-full of impurities, according to Straight Dope columnist Cecil Adams.)

A slightly less R-rated Superman analysis from physicist Adam Weiner posits a possible explanation for how the Man of Steel flies through the air.

One possibility is that he is able to emit high-velocity streams of air through the pores of his skin. As he forces the air out of his body, according to Newton's Third Law, the expelled air must push back, Weiner wrote in Popular Science in 2008.

In the same article, Weiner also pointed out that the Human Torch, from the Fantastic Four, who can ignite himself at will, shouldn't really be able to survive his superpower. Weiner calculated that the heat the Torch generates would break down his DNA and vaporize all of the water in his body.

Flying Through The Air With The Greatest Of Ease

Spider-Man's origin story gets slightly tweaked in the new movie that opened this month, with the rebooted Peter Parker, played by Andrew Garfield, trading in the biological webs used in the 2002 Tobey Maguire movie for ones he's built himself. But the wall-crawling crime-fighter could soon be altogether obsolete, thanks to some enterprising engineering students.

Utah State University engineers built a vacuum-powered apparatus that lets the wearer scale a tall building. As seen in the video below, the device, dubbed a Personal Vacuum Assisted Climber, or PVAC, by its makers, consists of two suction paddles powerful enough to allow just about anyone to scramble up the sides of buildings like Spider-Man:

Thanks to the PVAC, the students not only won a national competition sponsored by the US Air Force, but the military is now putting $100,000 toward taking the device even farther.

Spider-Man's other powers, such as strength, are relatively feasible, to a point. While spiders aren't quite the power-lifters that ants are, they're pretty tough little creatures -- mostly thanks to their small size. It's hard to see how you could transfer that proportional amount of strength to a heavy human, but if that were possible, you'd be a pretty effective crime-fighter.

Peter Parker is a materials engineering genius in his own right. His webslinging formula somehow manages to be compactly stored as a liquid, which then solidifies when shot out of a canister and is strong enough to bear both his weight and the forces of swinging around Manhattan.

Actual scientists are hoping to find a way to generate large quantities of spider silk for use in treating wounds and creating stonger, lighter artificial limbs and parachutes. But spider farms aren't exactly a practical option -- arachnids are way too territorial and aggressive to be kept together in large numbers.

Instead, scientists reached a happy medium by grafting bits of spider DNA onto the more tractable and commercially viable silkworm.

In a paper in the Proceedings of the National Academy of Sciences published in January, scientists from the University of Wyoming, University of Notre Dame and Zhejiang University in China related their success in genetically manipulating silkworms to make composite silk fibers using their own proteins and spider silk proteins.

Quantum Heroes

One of the more sophisticated superhero origin stories is that of Dr. Manhattan, a scientist transformed into an omnipotent being in Alan Moore's Watchmen graphic novel. In the book, Dr. Jon Osterman is accidentally locked inside a device called an Intrinsic Field Subtractor, which disintegrates him -- until his mind reconstructs a new, blue-skinned form for himself.

The 'intrinsic field,' which, according to the comic, is responsible for holding atoms together, is a made-up concept. But theoretically, if such a field did exist in the form of a wave, it would be possible to remove the intrinsic field from something, University of Minnesota physics professor James Kakalios -- the author of the book The Physics of Superheroes and a consultant on the Watchmen movie -- explained in a 2009 video.

The way to remove a hypothetical wave would be to generate another wave out of phase with the intrinsic field. The combination of perfectly aligned peaks and valleys would zero each other out.

There's not really a logical explanation for how Dr. Manhattan reconstitutes himself afterwards, but many of his powers, including teleportation and replication, have a foothold in reality. Supposedly, Dr. Manhattan has achieved a kind of quantum nirvana, with the ability to manipulate things, including himself, at subatomic levels.

In quantum mechanics, a wave passing through a certain boundary can seem to appear in several places at once thanks to a phenomenon called diffraction. A single laser beam, after passing through a screen, can appear as a group of discrete points on the wall thanks to the interference of the obstacle.

Dr. Manhattan has a wave associated with him that he can control at will. So presumably, when he chooses to diffract himself, he can be in several locations at once, Kakalios mused in his video.

When he's not consulting on Hollywood movies or researching the optical properties of amorphous semiconductors, Kakalios teaches a popular freshman seminar called Everything I Know About Physics I Learned By Reading Comic Books.

Whenever I use superheroes to illustrate physics principles, students never wonder when you're going to use this in real life, Kakalios said.

The tone of all of these scientific critiques is generally playful rather than huffy. Scientists are just nerds of a slightly different color, and they often show it; there's a flower gene named after Superman, a fruit fly gene called Batman, just to name a few examples.

What else could the root of all this overanalysis be but a love of both superheroes and science?