I went to go see The Incredible Hulk. I liked the Hulk since I was a kid. I think I was a fan of the TV series then later stumbled into the comic book. The Hulk is not realistic by any stretch of the imagination. Complex mammals like humans die when exposed to high levels of gamma radiation, nor is it likely to achieve such an amazing transformation.
But one thing made me laugh during the movie was the Hulk’s weight.
I know, I know — it’s a comic book. But being a science geek, I can’t help but notice this stuff.:-)
At first, it seemed obvious that the Hulk was heavier than Bruce Banner. Then a scene on a medical table clinches it when Banner does his transformation, and the table buckles underneath him. A table which can usually handle 200+ kg easily. But where the hell does that extra mass come from? The movie makes it quite clear it’s gamma-radiation fueled metamorphosis, but still: gamma radiation to mass?
One kilogram of mass is the equivalent of 8.98755179 × 1016 joules (or roughly 19 megatonnes of kilogram of TNT). Assuming 100% effeciency in conversion of course. (HA! As if…) But to get 1 kg of mass, that means Bruce Banner, weighing in at 128 lbs (according to the Marvel database), absorbed at least 1.5 × 1015 grays of radiation (1 gray = 1 J / kg). Doesn’t mean much, huh? Let’s change the numbers around ala Wikipedia to sieverts (Sv) so we can look up the effects. From what I can tell:
1.54798125 × 1015 grays * 1 (for Gamma radiation) = 1.54798125 × 1015 Sv ≈ 1 547 981 250 000 000 Sv
(this is a very rough estimate based on the idea Dr. Banner received a full body dose, if we were talking about a portion of his brain, then the numbers go up… a LOT!)
According to Wikipedia, the highest known dose was in the 100 – 180 Sv range, and each of the victims died. Of course they go to great pains to emphasise how lethal that radiation dose was in the movie and comic books, but still: 1.5 million gigajoules of energy per kilogram of his body. 336 megatonnes of TNT per kilgoram of his body. He wouldn’t have died—he would have vaporized! And that’s just to get one extra kilogram of mass.
Obviously, the extra mass must be coming from somewhere else, and it has to be denser than the air around him. If he was absorbing air, then his net buoyancy in the atmosphere would not affect his weight—exactly like inflating a balloon doesn’t increase its weight. So I gotta ask: where does the Hulk get his bulk? (pun intended)
P.S. If Banner did have protein bars stashed on him, then his weight still weigh the same since the bars are on his person.
P.P.S. No, I don’t have better things to do—it’s too dang hot here in Vancouver to sleep!! :-)