Spider-Man Physics: How Real Is the Superhero?FROM WIRED MAGAZINE:
First, three graduate students decided to myth-bust a scene from the second Spider-Man movie. In it, Spider-Man slings webbing from the front of a four-car subway train and stops it from plummeting into a river. The team, from the University of Leicester in the U.K., calculated that some spider silk is, in fact, strong enough to stop a runaway train, and published their results in the most recent issue of Journal of Physics Special Topics.
|Spider-Man’s silk is similar in strength to that produced by Darwin’s Bark Spider, which weaves the enormous web pictured here. Agnarsson et al., PLoS ONE/Wikipedia|
After considering the relative geometry of the train, webs, and buildings used to anchor the silk, the team calculated the amount of stiffness, or tensile strength, required to hold the train in place without snapping. That value is known as Young’s modulus, a measure of the stiffness in elastic materials, and works out to be 3.12 gigapascals (one Pascal = 1 Newton applied over a square meter).
Turns out, orb-weaving spiders produce silk that ranges in strength from 1.5 to 12 gigapascals — meaning that yes, Spider-Man could have stopped a moving train by flinging sticky silk at it. Coincidentally, the properties of the silk produced by Darwin’s Bark Spider (Caerostris darwini), an arachnid that lives in Madagascar and spins the largest webs observed (sometimes hanging from 25-meter long anchor threads), match those of the webbing Spider-Man deployed in this scene.
But it isn’t just Spider-Man’s silk that could be real. With the help of a new suit, the superhero’s ability to sense approaching people could also make the transition into reality. Victor Mateevitsi, a graduate student at the University of Illinois at Chicago, has built a suit that alerts its wearer to approaching humans. Called SpiderSense, the suit uses a suite of built-in microphones to sense the surrounding environment.
The microphones transmit high-frequency sound waves and monitor waves reflected by nearby objects. When a person or object approaches, the microphones can sense it, and they respond by producing pressure in the area of the suit closest to the object. Mateevitsi envisions using the technology to help the visually impaired, as well as cyclists dealing with road traffic, New Scientist reported.