This article is from WeChat public account:Principles (ID: principia1687), author: Zwicky, cover: Oriental IC
In many science fiction and movies, we can see similar storylines:
In order to find a new world suitable for human survival, the protagonist traveled through the spacecraft through the shortcuts of space and time, and reached the unreachable place.
The shortcut in this classic bridge is actually the “wormhole” we often hear. The wormhole is not out of fantasy, it is predicted in Einstein’s general theory of relativity. But so far, we have not found any traces of wormholes, so we are not sure whether the wormholes are real.
So, if there are wormholes in the universe, how can we find them?
In general relativity, wormholes are related to black holes. In a black hole, matter collapses into a point, or singularity. Once a substance enters a black hole, it is trapped forever. The wormhole has the same structure on the outside, but its center is not a singularity, but a tunnel that leads to another space region or another universe. When the substance enters the wormhole, it passes through the tunnel to the other side. The concept of wormholes was originally proposed by Einstein and Rosen, so sometimes they are also called Einstein-Rosen Bridge.
Because wormholes and black holes are similar, they look the same from the outside. So we have a hard time distinguishing them.
However, a new study tells us that there may be ways to distinguish them. Although black holes and wormholes have the same external structure, there can be something on the other end of the wormhole, but not on the black hole. This means that the orbit of a star orbiting a wormhole may be slightly different from the orbit of a star surrounding a black hole. If there is a star rotating around it on the other side of the wormhole, then the gravitational force of that star will pass.The wormhole dragging the star on this side caused the orbit of the star to deviate.
The wormhole has stars around it. If the gravitational field can propagate through the wormhole, the orbit of the star will be affected and deviate from the standard Schwarzschild orbit. | Image source: [1]
The researchers suggest that we might be able to test this idea in the galaxy. In the center of the Milky Way, there is a supermassive black hole with a mass that is millions of times the sun – Sgr A*. There is a good place to look for wormholes because the formation of wormholes requires extreme gravitational conditions.
For years, researchers have been observing a star named S0-2 near Sgr A*. If the wormhole does exist in Sgr A*, S0-2 will be affected by the gravitational force generated by the star on the other side of the wormhole, then S0-2 will deviate slightly from its orbit as time passes.
However, because the current equipment is not sensitive enough, we are not able to make such a probe. But with the advancement of observing equipment over the next 10 or 20 years, and our long-term observations of S2-0, we may end up achieving this goal.
A star named S0-2 runs around a supermassive black hole in the center of the Milky Way. | FigureSource: Nicolle Fuller/National Science Foundation
Researcher Dejan Stojkovic explained that when our detection technology achieves the precision required for observation, we may find that wormholes are the most likely explanation for explaining the slight deviation of the S2-0 orbit. But even so, we can’t be sure that it is definitely a wormhole, because there may still be other things that have not yet been discovered that interfere with the S0-2 movement.
It’s worth mentioning that if one day we really find a wormhole, it won’t be as described in science fiction – even if the wormhole can be traversed, humans and spaceships It is also unlikely to traverse from it. Because wormholes need a negative energy source to maintain, we still don’t know how to do this. Perhaps if we want to create a stable huge wormhole, we need some extra “magic”.
Reference Source:
[1] https://journals.aps.org/prd/abstract/10.1103/PhysRevD.100.083513
[2] http://www.buffalo.edu/news/releases/2019/10/035.html
This article is from WeChat public account:Principles (ID: principia1687) author: Zwicky