What exactly is a wormhole

Wormhole, also known as Einstein-Rosen bridge, is also translated as wormhole. It is a narrow tunnel that may exist in the universe connecting two different space-times. Wormhole is a concept first proposed by Austrian physicist Ludwig Frahm in 1916. It was assumed by Einstein and Nathan Rosen in 1930 when they studied the gravitational field equation. Instant space transfer or time travel.
This theory was proposed by Albert Einstein. Simply put, "wormholes" are thin tubes of space-time that connect distant regions of the universe. Dark matter keeps the wormhole's exit open. Wormholes could connect parallel universes with baby universes and offer the possibility of time travel. Wormholes may also be time-space tunnels connecting black holes and white holes, so they are also called "grey roads".
In theory, a wormhole is a space tunnel connecting two distant time-spaces, like a vortex in the sea, which is ubiquitous but fleeting. These space-time vortices are caused by a combination of stellar rotation and gravitational forces. Just as a whirlpool can bring the local water surface closer to the water bottom, it can make two relatively far away local spaces instantly close together. However, some people have hypothesized that a strange matter can keep the wormhole open, and others have hypothesized that if there is a strange matter called phantom matter, because it has both positive energy and negative mass, it can create a repulsive effect to prevent Prevent the wormhole from closing.
So far, scientists have not observed evidence of wormholes.