What is wormhole

astronomy Are there "wormholes" in the universe?

In science fiction films, wormholes come into play when the aim is to take people very quickly to distant parts of the universe - or when traveling through time. In this context, the wormhole is an abbreviation in the universe or a window into the future or the past. But that has only very little to do with what astrophysicists understand by a wormhole.

So what is a wormhole? If you imagine an apple through which a worm has eaten its way from one side to the other, that's a pretty good analogy to what physicists think of a wormhole. The apple - or more precisely: the surface of the apple - would represent the entire universe, so the worm would actually take a shortcut.

The apple and Einstein's curved spacetime

The comparison with the apple has something to do with Albert Einstein, specifically: with two central theses of this theory. The first is that space and time form a unit, namely the four-dimensional space-time. And the second is that this spacetime is curved wherever there is matter and energy. This brings us back to the apple: The rounded surface of the apple in this picture represents the curved space-time. The difference is: the apple surface is two-dimensional, space-time is four-dimensional - which is difficult to represent. Now let's imagine an ant walking over the apple. The ant is so small that it does not notice the curvature - just as we on the surface of the earth have the feeling that we are moving on a flat plane. But even if we were to drive straight for thousands of kilometers, our line of motion is actually curved. And it is similar with curved spacetime: We have the feeling that everything is flat, but everything is curved. We don't notice that, however, because everything we use for orientation follows this curve - including light rays, for example.

When the worm on the mug takes a shortcut

But there are a few other aspects where the comparison with the apple reaches its limits: For example, the apple is self-contained. An ant can walk around once on the surface and at the end is back where it started. This is not necessarily the case in the universe or in space-time. The image of the apple is crooked for another reason as well. Because when I say that the apple surface is the universe, the question naturally arises: What does the wormhole or worm belong to when it is in the middle of the apple? At this point, the physicists leave the image of the apple and try a different comparison: namely that of a cup with a handle. The cup also has a curved surface. But something special happens on the handle. Again, imagine an ant that has worked its way up to the bottom of the handle. To get to the upper end of the handle, she can crawl along the surface of the handle. But it can also take a shortcut and move over the actual cup surface from the lower handle to the upper one. Mathematically, this abbreviation is closer to the physicist's wormhole; H. they imagine that there can be structures in space-time similar to the handles of cups - only four-dimensional ...

Wormholes are a mathematical-physical construct

Nobody knows whether such wormholes really exist. A wormhole is just a mathematical-physical construct that could be possible under very specific conditions. So far, however, there is no evidence or evidence that they really exist. And even if they did exist, the question would remain, what are they really like, whether they can be used in a targeted manner or can they accidentally get into them?

And whether you would survive this trip through a wormhole is another matter entirely. In this respect, it is currently what it is: science fiction.

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