MCU: 10 Fascinating Facts Behind Thor (2011)

6. Why The Bifrost Is Definitely NOT A Wormhole

Given the film's focus on astrophysics and its attempts to ground the multiverse and the existence of Asgard in real world science, you'd think that they would have gone with an easily accessible term to explain how Thor can travel throughout the Nine Realms.

In that respect, you'd think that the Bifrost Bridge would have been explained as a wormhole, since that's one of the more well-known terms from science that has bled into mainstream vernacular. Instead, the film refers to the rainbow bridge as "an Einstein-Rosen Bridge" - which is a real scientific term associated with black holes and the theory of inter-dimensional travel.

But it meant nothing to lay fans, so why choose it over wormhole? Well, it turns out that Kevin Feige felt that the term was "too 1990s" with the association it held with Stargate (which also featured Norse Gods).