In science fiction, space explorers frequently zip through wormholes in space-time that are connected by two black holes.

Black holes may be doorways into wormholes. Would the wormholes look the same as the ones in "Star Trek"?

The mathematics of the universe doesn't rule it out, but it's probably not.

There is only one thing at the center of a black hole.

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There is a chance that a black hole and a mirror twin could form a wormhole. Traditional wormholes are predicted to be incredibly unstable, meaning they'd collapse when a single particle of matter enters them.

Physicists think that a wormhole could become more stable if it were formed from a black hole, but we don't know what will happen.

Einstein-Rosen bridges

Einstein's theory of general relativity helped scientists discover black holes. If you crunch down enough matter into a small volume, gravity will overwhelm every other force and shrink the matter into an infinitely tiny point known as the singularity.

One-way trips are called black holes. They can't escape once someone crosses their boundaries. Black holes were once thought of as a trick of Einstein's equations, but later it was discovered that they do exist.

The reverse of a black hole is possible thanks to the same mathematics. There is an event horizon surrounding a white hole. Instead of falling in and finding it impossible to escape with a white hole, a person could never reach the horizon from the outside because it was constantly flinging its contents out into the universe.

The simplest kind of bridge is when a black hole and a white hole are connected.

Not very useful

'Black holes' with Planck hearts would lack a true event horizon (like the one illustrated in this image).

Here we see an artist's illustration of an event horizon. (Image credit: AleksandrMorrisovich/Shutterstock)

There aren't very many bridges that are useful for crossing the universe. Behind the event horizon lies the entrance to the wormhole. A person would have to fall into a black hole in order to get in. Once someone crosses an event horizon, they cannot escape. If you enter the wormhole, you'll be stuck inside for the rest of your life.

Einstein-Rosen bridges are not stable. The bridge pinches off before anyone can use it to travel from one side to the other. According to a physicist at The Ohio State University, one doesn't really have a wormhole since one can't traverse it.

A very precise and careful arrangement of matter is required to create a wormhole. A single packet of light or photon would cause the collapse of the wormhole. The speed of light would cause the wormhole to tear itself apart quicker than a rubber band.

White holes don't exist in our universe according to physicists. White holes are not stable like their siblings. Once a small amount of matter falls towards them, it explodes. White holes would not last very long.

If wormholes exist, they probably aren't Einstein-Rosen bridges because of the uncertainty of the existence of white holes.

A spinning singularity

Take their spinning into account if you want to build a wormhole from a more complex black hole. Roy Kerr was the first to solve the math for black holes.

There is a ring in the center of a rotating black hole. It's possible that this ring can become an entrance to a wormhole, but the problem of stability is still there.

The Kerr hole has an "inner horizon" and an "outer horizon." According to Mathur, people believe that the inner horizon is not a stable concept and that small amounts of infalling matter will change the region inside this horizon. There is no clear result of this instability. The problem is that if matter falls towards the ring singularity, it encounters two different effects, one of which is the spin at the center of the black hole.

This is not a good situation, and things are likely to go wrong very quickly. The situation is so unstable that it might prevent the creation of the singularity. Physicists believe that the idea of a ring from a black hole will be replaced by a more concrete idea once we understand the objects.

It was originally published on Live Science