What is Wormhole ?

In 1916, the Austrian physicist Ludwig Flamm, while looking over Karl Schwarzschild's solution to Einstein's field equations, which describes a particular form of black hole known as a Schwarzschild black hole, noticed that another solution was also possible, which described a phenomenon which later came to be known as a “white hole”.

A white hole is the theoretical time reversal of a black hole and, while a black hole acts as a vacuum, drawing in any matter that crosses the event horizon, a white hole acts as a source that ejects matter from its event horizon.

Some have even speculated that there is a white hole on the "other side" of all black holes, where all the matter the black hole sucks up is blown out in some alternative universe, and even that what we think of as the Big Bang might in fact have been the result of just such a phenomenon.

Some theorists are encouraged to think that real counterparts may eventually be found or fabricated and, perhaps, used as a tunnel or short-cut for high-speed space travel between distant points or even for time travel (with all the potential paradoxes that might entail).

However, a generally accepted property of wormholes is that they are inherently highly unstable and would probably collapse in a much shorter time than it would take to get through to the other side.

At any rate, it is predicted that they would collapse instantly if even the tiniest amount of matter (even a single photon) attempted to pass through them.

Although some possible theoretical ways around this problem have been suggested (for example, using “cosmic strings” or “negative matter” or some other exotic matter with “negative energy”) to prevent the wormhole from pinching closed, the idea remains largely in the realm of science fiction for the time being.

It has, however, still not been mathematically proven beyond all doubt that some kind of exotic matter with negative energy density is an absolute requirement for wormholes...

Has it been established that such exotic matter cannot exist, so the possibility of a practical application of the theory still remains.

Because a wormholes is a conduit through 4-dimensional space-time, and not just through space, Stephen Hawking..

Others have also posited that wormholes might theoretically be utilized for travel through time as well as through space...

Although it is widely believed that time travel into the past will never be possible due to the potential for paradoxes and self-destructive feedback loops.

Wormholes connecting different points in space and time might seem like the stuff of science fiction, but these mysterious tunnels are an actual feature of theoretical physics.

Scientists have yet to find evidence of a wormhole in the cosmos, but the passages are mathematically possible according to Albert Einstein’s theory of general relativity.

In the same way that a piece of paper can be folded in half, general relativity states that high mass can bend the fabric of space itself.

In 1935, Einstein and physicist Nathan Rosen postulated that this process could result in a bridge forming between two previously separate destinations in space-time.

If general relativity holds true, then these “Einstein-Rosen Bridges,” or wormholes, could act as shortcuts to the far off reaches of the cosmos.

Without the luxury of directly observing a wormhole, scientists can only speculate on how they might operate.

A common theory suggests that a black hole—a point in space-time where gravity is so strong that even light cannot escape—might serve as the entrance.

This opening would connect to a tube, or “throat,” that would empty from a theoretical “white hole,” a point from which light and matter could exit.

Still, chances are slim that this kind of wormhole could be used for space travel.

The passages are likely to exist only on a tiny subatomic scale, and even if they were large enough to traverse, gravitational forces would cause them to collapse only an instant after they opened.

Scientists have theorized that wormholes made of a hypothetical exotic matter might contain enough negative energy to remain stable, but even then the addition of an outside object—like a spaceship—could cause the tunnel to fall apart.

Assuming the power of wormholes could be harnessed, their potential would be extraordinary.

By taking a shortcut through a stabilized wormhole, an object could arrive at its destination faster than a beam of light traveling in normal space, opening the door to the possibility of time travel into both the future and the past.