Back in February, Jen-Luc Piquant chatted with University of Minnesota physicist Jim Kakalios (author of The Physics of Superheroes, among other achievements) in Second Life's Virtually Speaking Science series. That same week, Neil de Grasse Tyson had taken to Twitter with a hypothesis about the possible physics behind who could (and could not) lift Thor's hammer, prompting bloggy responses from Kyle Hill and Matt Shipman. Kakalios had a rather elaborate counter-hypothesis that he described in detail, because he's such a fan boy. Physicists do love their superheroes. It was all in fun, but the story doesn't end there. I'll let Kakalios tell you the rest:

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Last Thursday, I stopped by my local comic book shop and picked up a copy of Marvel comics’ Indestructible Hulk No. 8. This comic, written by Mark Waid and drawn by Walt Simonson, featured a meeting of the Jade Giant and the Norse god of thunder, the Mighty Thor. In an earlier issue the Hulk had strained to lift Thor’s hammer, and seemed to have hoisted it over head. However, it turns out that the hammer Mjolnir, deploying its “homing” property, was returning to Thor’s hand while the Hulk happened to be grabbing the handle. In issue no. 8, this led to a conversation between the Hulk’s alter ego, physicist Bruce Banner, and another character as to why no one could lift Mjolnir, unless they were deemed “worthy.”

While no less an authority than Neil deGrasse Tyson has opined that Thor’s hammer is composed of neutron star material, this could not account for why some, such as Beta Ray Bill and Captain America (both of whom are apparently as worthy as Thor) have been able to lift Mjolnir, while the Hulk and Juggernaut can not. In last week’s issue of Indestructible Hulk, my proposal for this property of Thor’s hammer was described by Banner as his “favorite science-based theory.” [Click to see full-sized individual panels.]



The Backstory: A few months earlier I had written a chapter for a collection of essays titled Hollywood Chemistry to be published by the American Chemical Society: "The Materials Science of Marvel’s The Avengers – Some Assembly Required." In addition to discussions of the chemical composition of Captain America’s shield and Hawkeye’s bow from The Physics of Superheroes, I considered the suitability of a gold-titanium alloy coating for Tony Stark’s high tech suit of armor in the 2008 film Iron Man, and the nature of uru metal comprising Mjolnir.

When an earlier issue of the Indestructible Hulk featured Banner analyzing a sliver of uru metal, I thought that the science of the hammer may make an appearance in the storyline, and I sent the relevant portion of my chapter to Mark Waid.

Mark has been an early and enthusiastic supporter of my efforts to join superhero comic books and physics, and was a great resource when I was writing my book (back when the working title was My Mid-Life Crisis). He loved my proposed explanation for Mjolnir’s properties. (Spoiler Alert: As Thor and his hammer are completely fictional, any “scientific explanation” will require considerable suspensions of disbelief. My goal is not to provide a definitive explanation for something that is clearly fantastic and impossible, but to use an example from fiction to describe some potentially valid, real world science) and asked my permission to cite it in an upcoming issue.)

This e-mail exchange with Mark took place a while ago, and I had forgotten about it until last Thursday, when I saw my name featured prominently in the latest issue. I must confess that I smile to think that my musings on uru metal and graviton emissions may now be considered part of Marvel canon.

More importantly, if a reader of the Indestructible Hulk is inspired to learn more about gravitons in particular, and our understanding of gravity in general, then this would make me beam! Our scientific understanding of the world enables us to calculate the speed of objects (allegedly) tossed from high-rise buildings, and has transformed our economy through ever advancing technology enabled by federally funded research. It may even possibly enhance, in some small measure, our enjoyment of the escapist adventures of an eight-foot tall green giant and an Asgardian thunder god.