Thor’s Hammer Is Not That Heavy (But It Is Scientifically Interesting)

02.15.2013 |

In early February, astrophysicist Neil deGrasse Tyson said on Twitter that the superhero Thor’s Hammer (aka Mjolnir) “weighs as much as a herd of 300 billion elephants.” News outlets pounced on this, and the news was quickly circulating online. Sadly, Tyson was wrong.

Tyson’s reasoning was based on the idea that Mjolnir was “made of neutron-star matter.” Not so fast.

(Art by Mike Deodato Jr.)

“The critical mistake Tyson makes is thinking that Mjolnir was forged of the core of a dying star, when it was actually forged in the core of a dying star,” says Suveen Mathaudhu, a program manager in the materials science division of the U.S. Army Research Office, adjunct materials science professor at NC State and die-hard comics enthusiast. “It’s well documented that the hammer is made out of ‘Uru,’ a fictional metal from Thor’s native realm of Asgard.”

And Mathaudhu can cite documentary sources to back him up. For example, Marvel – which publishes the Thor comics – issued a “Thor’s Hammer” trading card in 1991 that states Mjolnir is made of Uru and weighs precisely 42.3 pounds. That’s lighter than a herd of 300 billion mice, much less a herd of 300 billion elephants. But it raises a different science question.

Using the dimensions and weight on Marvel’s trading card, Mathaudhu estimates that the density of Mjolnir is about 2.13 grams (g) per cubic centimeter (cc). That makes it even lighter than aluminum, which has a density of 2.71 g/cc. So what could possibly be that light and strong?

Mathaudhu has a theory.

“Perhaps Uru is the ‘holy grail’ of high-pressure physics: a form of metallic hydrogen,” Mathaudhu says. “Some predictions of the density of metallic hydrogen fall into this range, it requires extreme conditions to form, and could be a tremendous energy source. It’s thought to be present at the core of planets, such as Jupiter, and at the core of suns – which are stars, after all.”

While Tyson made a mistake in calculating the weight of Thor’s hammer, he succeeded in drawing attention to the sciences of astrophysics and materials science – which is a good thing. For more discussion of Thor, Mjolnir and physics, check out this interesting post on Scientific American’s site about momentum and how Thor can fly.



34 Responses to “Thor’s Hammer Is Not That Heavy (But It Is Scientifically Interesting)”

  1. ck says:

    Thors hammer can only be lifted by those who are worthy…that being said you have to add magic in this equation (this is based on the comic right?). For those who are worthy, it could weight 42 pounds but for those who arent….it could be Neil’s answer so good luck lifting that

  2. jon says:

    Its a MAGIC hammer. it MAGICALLY decides whos worthy enough to pick it up. the Hulk can easily become stronger than thor and still not pick it up.

    Whats this talk about science backing a marvel comic book?

  3. Ross says:

    Sounds like it is affected by gravity but is otherwise locked in quantum space. Only Thor can move it…

  4. I could have sworn I heard the fellow in the recent Thor movie say that Mjolnir was forged **of** the material of a dying star. If not, I stand corrected. And, I suppose, even if he did say what I thought, I stand corrected — I gladly defer (as should we all) to hard-core Comic Book people. But now you’re stuck making up all kinds of supernatural forces to account for the behavior of what is otherwise an obviously heavy object that even the Hulk can’t lift.
    -NDTyson, NYC.

  5. Clarke says:

    How does that explain why nobody else could pick up the hammer? I could easily lift 42 pounds.

  6. beta ray blog says:

    “”Whosoever holds this hammer, if he be worthy, shall possess the power of Thor.” is the inscription on the side, placed there by Odin. Hulk is not worthy, therefore he cannot lift it. It has nothing to do with weight or strength. It is an enchantment.

  7. I don’t know if the burden is suddenly on Prof. Mathaudhu to explain the supernatural behavior of Mjolnir (such as the Hulk’s–or anyone else’s–inability to lift it), any more than the burden would have been on Prof. Tyson to explain Thor’s ability to lift something as heavy as 300 billion elephants. Suspension of disbelief might be psychologically easier when it’s ONE guy lifting something that heavy, but both cases require some serious flexibility in the laws of physics. The only question is which laws are being bent in the Marvel Universe.

    That said, the fact that Prof. Tyson took the time to comment on this is AWESOME (that man should be president). I know Prof. Mathaudhu (well enough to spell his name without cheating), and I suspect his reaction is the same.

  8. JamesCurle says:

    Just wanted to appear in a comment thread with NDGT. You da man.

    Carry on.

  9. [...] On North Carolina State’s news blog, Matt Shipman has the story: [...]

  10. Patrick Gerard says:

    My degrees are in the arts but I will propose that the ability to move Thor’s hammer is magic… But I’d refuse to suggest that magic is scientifically uninteresting and may be especially relevant to areas of cosmology which have reached at concepts like the holographic nature of consciousness, a rather magical concept.

    Mathaudhu’s ideas seem pretty sound to me when it comes to the physical nature of the hammer. Keep in mind, the ability to lift the hammer is not limited to strength and fairly frail people have lifted it. The worthiness is tied to the spell and is about the beliefs, intent, and nature of the wielder; Thor’s strength doesn’t enable him to lift the hammer (it’s not especially heavy) but the spell prohibits other people from lifting it.

    But my own — totally casual — perspective on the spell and magic in general (and this may be nonsense):

    The hammer is contained in a closed space-like curve. Within this curve are alternate laws of physics (just as Star Trek warp bubbles defy physics and closed time-like curves defy normal rules of causality). The spell is a closed space-like curve and since the parameters of this spell are variable (ie. situational) then an outside force most likely continually monitors or adjusts the space-like curve or the hammer itself contains an artificial intelligence and a power source capable of modulating the space-like curve. (Or perhaps someone with an outside perspective of causality created a regression for the necessary space-like curve that would cause the laws of physics of the hammer to constantly vary but happen to be immobile at the chronological points where someone unworthy would attempt to lift it; if you can predict when the wrong person attempts to lift it, you can time the physical properties of the hammer to render it unliftable at those moments.)

    Likewise, the spells of someone like Doctor Strange may involve some kind of telekinetic or perception based geodesic manipulation to create highly specialized space-like curves. Effectively, it’s just creating special physical laws that apply in a localized region… and the tricky part is making those laws specific enough to adapt to desired contexts.

    So going with classic myth, a love spell (such as the kind the Enchantress uses) may simply be triggering special physical laws which cause the hypothalamus of a person to physically trigger certain chemical secretions by having it respond according to an internally consistent set of stimulii. For example, perhaps certain synapses have increased conductivity when other synapses are triggered as a special case of closed space-like curves in the brain.

    Basically, though, it’s just creating situational laws of physics that are more nuanced than the laws of physics in the external world.

    Just a thought, anyway.

  11. David Pizarro says:

    I don’t know if the burden is suddenly on Prof. Mathaudhu to explain the supernatural behavior of Mjolnir (such as the Hulk’s–or anyone else’s–inability to lift it), any more than the burden would have been on Prof. Tyson to explain Thor’s ability to lift something as heavy as 300 billion elephants. Suspension of disbelief might be psychologically easier when it’s ONE guy lifting something that heavy, but both cases require some serious flexibility in the laws of physics. The only question is which laws are being bent in the Marvel Universe.

    That said, the fact that Prof. Tyson took the time to comment on this is AWESOME (that man should be president). I know Prof. Mathaudhu (well enough to spell his name without cheating), and I suspect his reaction is the same.

  12. Tom H says:

    According to Norse mythology, the hammer was created by the dwarves, and the type & source of the metal was never really discussed. In the comics, “uru” is a metal found in Asgard – In one mid-1960′s issue, Thor is seen carving a substitute hammer out of a cliffside, which would indicate that the cliff was either a very pure vein of uru, or that the writing was very sloppy… But the lore of the comic is not that the hammer is heavy (and only Thor is strong enough to lift it), it tells us that Odin’s enchantment makes it to that only those WORTHY can lift the hammer. That’s why the Hulk can’t lift it, even though his strength is equal to or greater than Thor’s, but the alien Beta Ray Bill was able to easily heft the hammer. The comics have been maddeningly inconsistent as to whether machines can lift it, although if Thor leaves the hammer on a table, the table won’t collapse.
    Hope that helps!
    Tom Harris
    (Host of the Radio Free Asgard podcast)

  13. Daniel says:

    Thor is a “God” , not a witch.
    So his hammer would be a divine hammer, not a magic hammer.

  14. Sean Meaney says:

    Actually Thor’s Hammer is Zero Mass. Because this Rule: A/0=/A. Thus g/m=a or g/0=/g thus a=/g which means as a zero mass object Thor’s hammer is exerted on by /gravity (a gravity not of this universe).

    So out there is a particle of zero mass with an acceleration of /g.

  15. “The only way of discovering the limits of the possible is to venture a little way past them into the impossible.” – Arthur C. Clarke (Profiles of the Future, 1973)

    “Well… magic’s just science that we don’t understand yet; Arthur C. Clarke” – Jane Foster (Thor, 2011)

    Wow… my mind is blown that everybody is onto this, but mostly that NDTyson took the time to read, consider and post; This is the highlight of my year. I should point out that he does not “stand corrected”. His tweet started with “If”, so it really doesn’t matter what he’s saying it’s made of; it wouldn’t necessarily be wrong. As David Pizarro states, the burden of proof doesn’t necessarily fall on either one of us. The conjecture and discussion is a truckload of fun, but I suppose it depends on how much a truckload really weighs.

  16. [...] who’s also an adjunct materials science professor at North Carolina State, tells the NC State Newsroom. “It’s well documented that the hammer is made out of ‘Uru,’ a fictional metal from [...]

  17. tdonaldson says:

    Did anyone think to ask what the carrying capacity of the SHIELD Helicarrier is when fully loaded? I’m no scientist, but I think the fact that the Helicarriar was in flight through Thor’s entire time on board, this might suggest a fallacy in the logic of 300 billion elephants, which works out to about two trillion tons.

  18. Garth Croft says:

    Why even go with ‘magic’?

    We have quantum theory!

    Let’s look at it this way: Physics at the core of a star is a bit different than what we’re used to when taking a walk through the park.

    On one hand, the ‘metal’ of the hammer could be as deGrasse Tyson describes or as can be found in most Stephen Baxter novels: ‘Densely packed neutrons’ or ‘neutron star matter’. This would make it the most dense substance we can imagine outside of a black hole and would indeed weigh an enormous amount and be impossible to lift in Earth gravity (Heck, it would take an enormous amount of energy just to get it moving in vacuum outside of any gravity well).

    On the other hand, the metal could be ‘metallic hydrogen’. This would explain the lightning, right?

    But what if, as Tevye said, “There IS no other hand!”? What if the Hammer, being forged of material from the core of a star where particles behave *very* strangely, exists in BOTH states at once?
    Or, more appropriate to the circumstances, exists in one state for some, and another state for others.

    When Thor picks up Mjolnir, his perception resolves its quantum state as metallic hydrogen. Same goes for the ground it is on or the table upon which Thor rests it (thus not punching a hole straight through the mantle to the Earth’s core). Lightning? Sure! As far as we know, metallic hydrogen may be very energetic.

    When the ‘unworthy’ attempt to lift it, however, its quantum state resolves into a neutron mass, becoming immovable for *that* individual.

    Let’s even pretend that Thor, son of the All-Father Odin, can *manipulate* its quantum state. According to quantum theory, quantum states are manipulated by observation, and we might assume that a god could get a handle on that. That way he can easily swing it, and then while in relative motion impart great mass to it which would easily lift him skyward. Sure, that’s seriously cheating physics, but quantum mechanics kinda does that already… just on a much, much smaller scale.
    Indeed, existing in two states at once would explain why Mjolnir itself can sit gently on the ground while the one who attempts to lift it sinks into the earth.
    It would also mean that when Thor decides to strike something with it, it can do so with the force of “300 billion elephants”… pretty much what it would take to make an Incredible Hulk reel.

    So, thanks to the phenomenon of quantum theory, Mjolnir would work like magic in the hands of one who could manipulate its quantum state, while for very specific ‘unworthy’ sorts, they would indeed be trying to lift Neil deGrasse Tyson’s “Herd of 300 billion Elephants.

  19. [...] worth reading as food for thought as much as a dose of reality. While your thinking caps are on, just how heavy is Thor’s hammer? (warning: experts disagree!) While you’re in high gear, Warren Ellis encourages you to go [...]

  20. [...] story: The Abstract :: North Carolina State University :: Thor’s Hammer Is Not That Heavy (But It Is Sc… Share this:TwitterFacebookEmailLinkedInGoogle +1PinterestLike this:Like Loading… This entry was [...]

  21. [...] wrote a blog post in February that begins this way: “In early February, astrophysicist Neil deGrasse Tyson said on [...]

  22. digritz says:

    Science and Thor’s hammer fine. I got no problem with that. The difference “Forged of a dying ” and “In a dying star” would seem to be totally irrelevant.

    If a material is forged at the heart of a dying star it could most certainly take on the aspects of the environment it is forged in. In this case incredible pressure. Now I can see a demigod being able to handle this but the material being forged. I don’t care if it’s Uru, Aluminum or bird shit. It’s going to be dense and as heavy as the atmosphere it is created in. Unless you add in magic. Then you can throw any and every theory out the window no matter how many degrees follow the name.

    Please remember that a star doesn’t start out as dense as it becomes when it’s dying or dead. IT’S MADE OF GAS! How does it become so heavy…. PRESSURE!

    Also one final thought there are others that have in fact picked up the hammer who were clearly unworthy. But it wasn’t easy which means it has another component aside from the enchantment. IT’S HEAVY!

    Materials scientist my rear end.

  23. [...] Suveen Mathaudhu, a program manager in the materials science division of the U.S. Army Research Office, adjunct materials science professor at NC State and comics aficionada says that Tyson made a critical mistake. [...]

  24. Frank says:

    You guys must not actually read much. Only Thor can wield the hammer, not even Odin can hold it with or without enchantment. However the only reason why Thor can is because he was given a magical belt which give him the ability to use it. Hulk can and has picked it up before but he isn’t able to just do as be pleases and swing it around like Thor can.

  25. Jon Pugh says:

    I’d like to point out that while Beta Ray Bill was able to pick up the hammer in his run of Thor’s comic, the more interesting moment came in a great crossover comic where Wonder Woman was able to pick it up, because she is obviously worthy.

    http://images4.wikia.nocookie.net/__cb20081224185741/marveldatabase/images/9/98/Beta_Ray_Bill_(Earth-616).png

    http://media.comicvine.com/uploads/4/43247/840891-wwandstorm_super.jpg

  26. Jon says:

    Lol at all the people trying to explain it with science. It doesn’t matter. It was a hammer forged in the heart of a dying star. A hammer. Odin spoke the enchantment into it, stating only those worthy can lift it.

    He spoke the enchantment into it. This is the same guy who stripped Thor of his powers with a thought. Explain that with science. It has nothing to do with science, and physics. Due to the enchantment, the Hammer is a judge of character, and has a special bond with Thor, or one who can wield it, and can be summoned with a thought. It doesn’t need to be explained scientifically, when the hammer was given these properties by a vocal statement, by a man who was able to strip the Thunder God of his powers with a mere thought. No science here, it can’t be explained by science, just pure fictional divinity.

  27. Jon says:

    and for Franks comment, you are wrong. Thor can lift it cause he is worthy. Not due to his belt of strength, which has nothing to do with Mjolnir, or his powers. Hulk has never lifted it before, not canonically.

  28. Jon says:

    and also, to digritz, no one “unworthy” has lifted the hammer, period.

    The hammer is NOT super heavy, that only becomes light when someone worthy picks it. The Hammer is a judge of character. Odin spoke an enchantment into it, it has nothing to do with weight, so stop trying to explain it as super dense, when that has nothing to do with it, yeesh guys. All you smarty pants just look, well, ignorant.

  29. […] used that as an excuse to write a series of posts about physics and materials science related to Thor, Iron Man (twice!), and Wolverine. It helps that I know a materials researcher (Suveen Mathaudhu) […]

  30. Just Johnny says:

    THOR is much more powerful than the Hulk , if THOR wanted he could crush the Hulk ! The Hammer can only be moved by THOR and His Father ODIN .

  31. Michael Borg says:

    As much as I thought NDT’s explanation was cool, I have to side with the “42 lbs., but enchanted” answer.
    For one thing, the crater it makes when it lands on Earth in the first Thor Movie would be more commensurate with a 42 lb. object moving at astronomical speeds. If Mjolnïr weighed as much as 300 billion elephants it would’ve obliterated the entire planet.
    Secondly, we all know that “42″ is the answer to The Great Question of Life, the Universe, and Everything, so it’s not unreasonable to think that a demigod’s primary source of power would involve that number somehow (yes, I’m aware that I’m mixing two different franchises – so sue me).

  32. […] enormous energy, such as a blow from Thor’s hammer, strikes Cap’s shield, that energy needs to go […]

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