Astronomers know that the Universe is not only expanding, but it does so at an ever-increasing rate. These conclusions are based on the discoveries of scientist Edwin Hubble, who confirmed in 1929 with his observations that the expansion rate is increasing. To better visualize the expansion of the Universe, we can imagine galaxies moving away from each other. Simplistically, this can be illustrated as follows: when you bake bread or muffins, the dough expands in the mold, filling its space. The Universe is expanding in the same way, but it doesn’t have a baking mold – it is expanding into itself.
This idea may seem paradoxical, since the Universe is all that exists. There is no “mold” limiting it in size, only the “dough” itself – space, matter and energy. Even professors of physics and astronomy find it difficult to fully comprehend this phenomenon, as it has no parallel in our daily lives.
Mystery of dark energy
The Universe emerged about 13.8 billion years ago from the Big Bang, a process where an ultra-dense and hot spot began to expand rapidly. In the initial stages, there was an inflationary phase during which every point in space rapidly increased. Then matter, light, and finally the stars and galaxies were formed, the ones we observe today.
Alexander Friedman back in 1922 mathematically proved the possibility of the expansion of the Universe, and Hubble confirmed with his observations that it was indeed happening. However, it remains a mystery what force overcomes gravity in an effort to stop the expansion. Scientists call this force dark energy, because it has not been directly measured or seen. According to models, dark energy makes up about 68% of the Universe’s total energy, while ordinary matter makes up only 5%.
Dark energy causes an accelerated expansion of the Universe, which scientists often depict as an “expansion funnel” infographic. Imagine the narrow end of the funnel representing the beginning of time and its wide part symbolizing the present state of the Universe.
Unresolved problems of modern physics
Another mystery is the attempt to reconcile quantum mechanics, which describes the behavior of matter on small scales, with gravity, which operates on larger ones. In the quantum world, energy is discrete and objects can disappear and reappear like waves. In the classical world as we are used to seeing it, objects behave predictably and have continuous energy. It has not yet been possible to unify these two theories.
One possible solution is the multiverse theory, which assumes the existence of multiple Universes with different physical laws. This may explain how quantum and gravitational phenomena can coexist. Other theories, such as string theory or loop quantum gravity, also attempt to solve these problems.
Despite these difficulties, the expansion of the Universe continues. Over time, galaxies become more distant and the Milky Way gradually loses contact with most other galaxies. The future of the Universe remains a mystery that scientists are only beginning to unravel.
We previously reported on how the expansion era of the Universe was coming to the end.
Provided by Science Alert
