A Marvel science adviser explains the physics of Thor's new weapon in 'Avengers: Infinity War'

The Marvel Cinematic Universe may have aliens, stones that control space and time, and a giant angry green man. And while all that seems unrealistic, some of the fundamental ideas presented in "Avengers: Infinity War," and other Marvel films, is based on real science.

Here to explain more about one particular aspect - Thor's hammer and new weapon - is USC Professor of Physics and a Marvel movies science advisor, Clifford Johnson. You can also check out Johnson's graphic novel "The Dialogues: Conversations about the Nature of the Universe." Following is a transcript of the video.

Clifford Johnson: One of the really fun things that's going on in contemporary, real physics research is that there is very exotic phases of matter that can occur in the universe in extreme situations. One of the extreme situations is when you have a lot of gravity that allows you to compress that matter into a very, very compact, dense form. And a lot of gravity is available when you have, for example, the interior of a star. So, well-known, exotic place is the core of what's called a neutron star. So much of the matter, imagine having as much matter as our sun, which is a huge object or even more, but compress that down to the size of let's say, Manhattan, New York City. That is incredibly dense, the matter inside takes on a very, very different form. It takes on very, very different properties.

And one of the early conjectures from the Marvel Universe and you see a little bit of it in the Marvel Cinematic Universe as well, is the idea that maybe material like that is where Thor's hammer gets some of its incredible density. Now, we know that Thor's hammer has gone away and it is replaced in Infinity War with a new weapon and so what you get is a little bit of a taste, a closer look at how such weapons are manufactured. And that is sort of a fun thing because you can then speculate about whether the properties of those instruments are just from the physics of those exotic materials that you find in the cores of stars or whether they are just holders, 'channelers' if you will like of Thor's inherent ability. And I think we learn a little bit from "Thor: Ragnarok" that the power is really in him and the hammer is really more of a channel. And I think the skill then, that these dwarfs have, is how to build weapons that are the best possible channels for the inherent power that our hero has. And so, the new device, the new hammer, Stormbreaker is presumably even better design than Mjölnir had to channel Thor's abilities.