An imaginary passage through the structure of time and space. Wormholes can be imagined as a shortcut through time and space, that is, a cosmic tunnel connecting two black holes or (more speculatively) a black hole and a white hole. The' other end' of the wormhole can be anywhere in space or at any time, so that any object passing through the wormhole can appear in other parts of the universe in an instant-not only in another place, but also at another moment.

The solution of the general relativity equation describing the wormhole was actually discovered in 19 16 years shortly after the theory was put forward, but it was not explained at that time. Albert Einstein himself cooperated with nathan rosen in Princeton in 1930, and found that the black hole represented by Schwarzschild's solution is actually a bridge between two flat space-time regions (now called Einstein-Rosen Bridge). Although these equations are studied as mathematical masterpieces (especially the work of john wheeler and his colleagues), no one regards them as the real characteristics of the universe before 1985, because all the examples studied in mathematics can only be opened for a short moment, and then slammed again before anything including light passes through the tunnel (according to the equations).

Although this idea is loved by science fiction writers, scientists generally believe that there must be some natural law that prevents the existence of wormholes. However, when the relevant scholars of California Institute of Technology tried to prove this in the1980s, they found it impossible. There is nothing in general relativity (this is the best theory of gravity and space-time that we have, and it has passed all the tests on it) that prohibits the existence of wormholes. Not only that, Kip Sonny and his colleagues also found that Einstein's equation even has a solution that allows long-lived wormholes.

The mouth of this wormhole should look like the horizon of a spherical black hole, but there is an important difference. The horizon is a one-way surface, from which nothing can be seen. But the surface of the wormhole allows two-way traffic. If we look at a wormhole near Vega at the other end, we will see Vega's light coming out of the tunnel-observers near Vega will also see sunlight when they look at the same wormhole from the other end.

But it is still extremely difficult to build a large wormhole that humans can cross (see time travel), and it may be impossible for all practical purposes. But physicists are interested in the possibility of natural wormholes with Planck length. This wormhole provides a basic foam-like space-time structure, and the space-time fabric itself is woven from wormhole fibers (using a mixed metaphor similar to poetic rhetoric).

If so, there will be many strange possibilities. For example, this tiny (ultra-submicroscopic) wormhole can connect distant regions in the universe, so that information can be leaked, thus ensuring that the physical laws on the earth are the same as those on distant quasars. Or a small wormhole breaks away from our universe and begins to grow into an independent universe through skyrocketing.