**Do you remember the movie Interstellar (2014) or even “Event Horizon” (1997)?** In these films the human is able to jump into a wormhole and emerge in a totally different galaxy, in another area of the universe. And it is that wormholes represent a fascinating concept in physics that **presents some very particular tunnels that connect two different points in space-time.**

## A basic pillar of science fiction

However, most of the main hypotheses surrounding wormholes suggest that they would collapse as soon as they were formed due to their instability – as shown in the *Another Life* (2019) series -. However, **a new theory postulates that these Einstein-Rosen bridges can remain stable enough so that objects enter one side and exit the other, that is, they can be used as shortcuts through space-time.**

This theoretical interstellar phenomenon works by tunneling between two distant points in space. In the new work, by physicist Pascal Koiran of the *École normale supérieure* de Lyon (France), he analyzed this figure using a different set of techniques and found that a particle could be documented crossing the event horizon into the wormhole. , traverse it and reach the other side in a finite period of time **. If a particle can get through a wormhole safely, humans could also get through it with a spaceship and reach a distant planet in a distant galaxy.**

## Wormhole metrics

**The rules of physics are fixed,** but there is freedom in the way coordinates are described mathematically, which are known as **metrics** .

To reach this conclusion, Koiran did not use the **Schwartzchild metric** (which describes the gravitational field outside of a spherical mass, assuming that the electric charge of the mass, the angular momentum of the mass, and the universal cosmological constant are all zero), but the **Eddington-Finkelstein metric** , in which a pair of black holes are used, although with some variation.

The mirror image of a black hole, the **white hole** . The black hole does not allow anything to go out – no object can escape the attraction of a black hole – and the white hole – in theory, as they have not yet been discovered – does not allow anything to enter. **To make a wormhole, just take a black hole and a white hole and join their singularities (the points of infinite densities at their centers).** This creates a tunnel through space-time. Thus, with this coordinate system used in the geometry of black holes, the researcher found that when the Eddington-Finkelstein metric was used, a particle could be seen crossing the event horizon towards the wormhole, going through the wormhole. and come out the other side. He was then able to trace the path through a wormhole using this metric with greater precision than is possible with the Schwartzchild metric, **concluding that the wormhole was stable, without the need for the exotic matter to remain open.**

Of course, **this does not necessarily mean that jumping through any black hole will transport us across the universe** . However, it raises a very interesting theory that shows that wormholes would not instantly collapse as soon as they arise.

*Referencia: Infall time in the Eddington-Finkelstein metric, with application to Einstein-Rosen bridges Pascal Koiran*

*Comments:**To appear in International Journal of Modern Physics D**Subjects:**General Relativity and Quantum Cosmology (gr-qc)**DOI:**10.1142/S0218271821501066**Cite as:**arXiv:2110.05938 [gr-qc]** **(or arXiv:2110.05938v1 [gr-qc] for this version)*