Threading the needle & then some

A traversable wormhole would be a shortcut through space. (ESO/L. Calçada

Seems traversable wormholes are possible but how traversable remains the question of the day.

Wormholes are an old idea in general relativity. It's based on work by Albert Einstein and Nathan Rosen, who tried to figure out how elementary particles might behave in curved spacetime. Their idea treated particle-antiparticle pairs as two ends of a spacetime tube.

This Einstein-Rosen Bridge would look like a black hole on one end, and an anti-black hole, or white hole, on the other end.

At small scales gravity must have a quantum nature. Credit: The Wolfram Physics Project

But all is not lost. We know that Einstein's theory must break down at quantum scales because it is a classical theory. Presumably, there is some quantum theory of gravity that supplants general relativity.

We don't yet have a complete quantum gravity model, but we do have several approximate models that will point us in the right direction.

One of these models is known as the Einstein-Dirac-Maxwell theory. It is so named because it includes aspects of Einstein's theory of gravity, Maxwell's theory of electromagnetism, and Dirac's theory of quantum particles. Recently a team found a wormhole solution to the Einstein-Dirac-Maxwell equations.

The team found that their wormhole solution was fully traversable. What's more, the solution doesn't require any negative-energy states. In principle, that would allow you to travel through the wormhole without needing negative mass. The only catch is that you would need to be in a quantum state. So microscopic clumps of atoms could travel through this wormhole, but not people.

End result ...

While this is interesting work, it is just a toy model. There are lots of solutions to Einstein’s equations that can’t exist for reasons beyond gravity. The team plans to explore their idea further to see if their solution is yet another impossible idea, or whether there might be a way to create this kind of quantum wormhole. And if this idea does work, it will still be easier to pass through the eye of a needle than it will be to enter the distant heavens.

It's still worth a shot, right? :)