Super-Saves!

First things first: I love the Big Bang Theory. I've only recently discovered it (though people have been telling me for years now that I would love this show) and am slowly working my way through its first season. Expect many BBT-related postings in the future; this will be the first.

This exchange (from Season One's "The Big Bran Hypothesis") caught my attention:



(If the video doesn't work, check out the clip here on youtube.com)

According to Sheldon, this famous save would never have been possible, since Superman's failure to conserve Lois Lane's momentum when he caught her would essentially kill her (though I don't imagine that his arms of steel would be sharp enough to chop her into three equal pieces; there would likely be something more like extensive crushing injuries involved).

This reminded me of another famed moment in superhero history: the death of Gwen Stacy. The exact same laws of physics apply to this situation--Gwen Stacy is falling from a bridge and, in an effort to save her, Spiderman (who, as a scientist himself, really should have known better) shoots a web that catches her ankle and arrests her fall. Though he did keep her from smashing into the ground, the abrupt way in which he had stopped her fall snapped her neck and killed her.



Physicist and professor Dr. James Kakalios explains it better than I ever could (Seriously, if you're even the slightest bit interested in the science of superheroes, check out his book "Physics of Superheroes". It's an interesting and entertaining read!).

Dr. Kakalios on the Death of Gwen Stacy

Let this be a lesson to all of you superheroes out there: if you want to save someone in free fall, match his or her speed, remember to conserve momentum, then decelerate. :)

Disclaimer:
The Big Bang Theory is owned by CBS; Spider-man is owned by Marvel Comics, and Superman is owned by DC Comics. No copyright infringement intended.

The Pursuit of Spidey-ness

In a minor digression from lecture, my professor claimed that in no way could Spiderman ever exist.

His rationale:

If you took the actual volume--assuming one cm diameter--of the webs he shoots out, and you calculate the amount of water mass in one cm over 100 m, it’s over half of his body weight. He’s a little weenie guy – one shot and he’s gone.

Okay… Let’s have a look at this.

Let’s assume that Spiderman’s webs are pretty saturated with water, say, 50% of their composition. For a web that is 100 metres long (10 000 centimetres) and one centimetre in diameter, we have a total volume of approximately 7,850 cm3 -- 3,925 cm3 of which would hypothetically be water.

The adult male body (age range 20 – 29) is on average about 60.5 % water (±7.1 %), and so if Peter Parker is something like 65 kg, that would give about 39.325 L of water. One web shot would take up over one tenth of his body’s water. More than that would leave him drier than a raisin unless he were constantly guzzling water.

It would seem then that my professor is on the right track, and that there is little hope out there for Spidey-hopefuls, but he missed one crucial fact: unlike in the 2002 film in which our hero somehow develops some nifty wrist glands to squirt out webs, the original comics had science geek Peter Parker develop a synthetic web and mechanical wrist shooters. Extra web is stored in a cartridge belt for easy and convenient reloading. So, apparently this weebly little guy can work his way around fluid shortage.

I wouldn’t be surprised, though, if humans could be engineered to make their own web proteins; the issue isn’t so much making the proteins as getting them out of the body once they are made. It has been done with goats such that they produced web silk protein in their milk… Let’s just say that I don’t exactly look forward to the human version of this experiment.

So, you’ve got your Spiderman outfit, and you’ve built yourself some web shooters and some synthetic web. Are you Spiderman? Can you climb up walls?

Since you’re probably not sprouting barbed microhairs on your finger pads, you should probably get yourself some gecko gloves.

Yep, gecko gloves. If you’ve ever seen a gecko, you probably know that they stick to pretty much anything. Some folks out there have designed gloves and boots that imitate the sticky hairs on gecko feet, and they are estimated to be able to support a mass of about 1160 kg (hopefully enough for you and whoever you’re saving). There are also designs for hairy spider feet-imitation gloves that can support about 480 kg, and crazy van der Waals gloves that can theoretically support approximately 40 000 kg (!). Also, these gloves are superhydrophobic, so water just rolls off them and they won’t get all gunked up with your water-filled webs.

Alright now, kickin’ costume: check; webs: check; gecko gloves: check. What about super strength and Spidey sense? Well, short of taking steroids (…) and developing ESP, the long-and-short of it is that it is very unlikely that things’ll work out in your favour.

That aside, hurray, you’re Spiderman! Go save some civilians!

Though, really, anyone bitten by a radioactive spider would probably die of blood poisoning before anything super awesome like, oh I don’t know…the reorganization of his or her genetic blueprint … could occur.

(Don’t just take my word for it – I’ve got references!)

Gosline JM, Guerette PA, Ortlepp CS, and KN Savage. “The mechanical design of spider silks: from fibroin sequence to mechanical function”. Journal of Experimental Biology. 1999. 202: 3295 – 3303.

Kakalios J. The Physics of Superheroes. Gotham Books: New York, NY. 2005.

NM Pugno. “Towards a Spiderman suit: large invisible cables and self-cleaning releasable superadhesive materials”. Journal of Physics: Condensed Matter. 2007. 19: 1 – 17.

Vollrath F and DP Knight. “Liquid crystalline spinning of spider silk”. Nature. 29 March 2001. 210: 541 – 548.

Watson PE, Watson ID, and RD Batt. “Total body water volumes for adult males and females estimated from simple anthropometric measurements”. January 1980. The American Journal of Clinical Nutrition. 33: 27 – 39.