Odin, Thor’s father, ordered the

dwarfs to forge Mjölnir (Thor’s

Hammer). The blacksmiths Eitri,

Brok, and Buri used the core of a

dying star to forge the hammer.

 

According to marvel Mjölnir is made of

‘Uru’ and has a mass of 42.3 pounds (about 19 kg).

Uru is a fictional metal from the realm of Asgard.

 

So what might Uru be?

Using the volume of Mjölnir given by Marvel the hammer

would have a density of 2.13 g / cm3. This is lighter than

aluminium with a density of 2.71 g/cm3.

 

What it could be isa form of metallic hydrogen which has been predicted to exist in the core of large planets like Jupiter and in the core of stars. This metallic hydrogen would be about the right density to match Mjölnir’s statistics. Hydrogen takes on metallic properties under extreme pressures and becomes a superconductor. A superconductor is a material with zero resistance to electric current (which would make it an excellent lightning conductor).

 

The only small problem with this is that so far only liquid metallic

hydrogen has been formed and only under extremely high pressure.

So maybe an alloy (combination of metals) using hydrogen and another

metal like lithium would reduce the required pressure and make it solid.

 

The other question is how does Mjölnir prevent itself from being

picked up by anyone unworthy? A possible explanation is that it

doesn’t change its mass, but only the force acting on it due to gravity.