It has been over ninety years since the fundamental concept of Schwarzschild Wormholes (also called Einstein–Rosen Bridges) was first proposed. Over the years, scientists have been trying to determine if wormholes are actually a physical reality, and if they do exist, whether they are traversable in nature.

Two challenges exist for the traversable wormhole hypothesis:

1. Building a stable wormhole would need the presence of a different, non-normal matter (often called exotic matter by the scientific community.) This is because general relativity indicates that the gravitational forces of normal matter in the wormhole will close the tunnel.
2. Wormholes are generally considered to be microscopic in nature, and macroscopic travelers (e.g., humans) would need larger-sized ones that may not be possible within the realms of known physics.

In 2017, physicists Ping Gao, Daniel Jafferis and Aron Wall proposed that the gravitational backreaction of a quantum matter stress tensor (with negative average null energy) would render the Einstein-Rosen bridge traversable. Quantum entanglement would provide the exotic matter that is needed to ensure wormhole stability. This is an important step in trying to address the first challenge.

The second challenge is still out-of-bounds for known physics, but scientists are making slow progress on that front as well. For instance, earlier this year, Durham University published their efforts to construct traversable wormhole solutions using the negative Casimir energy of the Alfven wave modes. This follows the research published by Princeton last year on leveraging the Randall Sundrum II model for traversable wormhole solutions. These are very, very small steps, but the good thing is that scientists are able to move ahead to realize what has been considered science-fiction over the years.