It is believed that our universe was born on 13.8billion years ago after the Big Bang and has been expanding with acceleration ever since. However, what exactly happened in the first seconds after the birth of the Universe - inflation - for a long time remains a mystery to physicists. According to the new hypothesis, as told by Live Science, in a relatively young universe, "the observer must be shielded" from direct observation of the smallest structures in space. In other words, physicists, by definition, will never be able to model inflation with conventional tools, and they will have to figure out a better way. The new hypothesis points to a specific feature of inflationary models that take very, very small fluctuations in spacetime and make them larger. But since a complete physical theory of these small fluctuations does not exist, inflation models with this feature (that is, almost all) will never work. Let me remind you that observations of the large-scale structure of the Universe and the remnants of light from the Big Bang earlier showed that in the very early Universe, our cosmos was probably going through a period of incredibly rapid expansion.
Evolution of the early universe
Today we know that as a result of inflation,In the smallest fraction of a second, the universe has become trillions and trillions of times larger. In the process, inflation also made our cosmos a little uneven: as it evolved, the smallest random quantum fluctuations - fluctuations built into the very fabric of spacetime - became much, much larger, which meant that some areas were more densely packed with matter than others.
After all, these submicroscopic differencesbecome macroscopic ... and even more, in some cases extending from one end of the universe to the other. Millions and billions of years later, these tiny differences in density have grown to become the seeds of stars, galaxies, and the largest structures in space. But if inflation in the early universe made our universe as we know it today, then what exactly drove inflation into action? How long did it last and what stopped it? Alas, scientists do not have answers to these questions - they simply lack a complete physical description of this significant event.
Another mystery is that inIn most inflation models, fluctuations on extremely small scales are inflated into macroscopic differences. These differences are incredibly tiny and would require a new theory of physics to describe reality with them. This, by the way, is already looming on the horizon, which I talked about in more detail in this article.
Different approaches to understanding inflation
Since scientists do not have a theory that unitedFor physics at high energies and small scales (for example, under conditions such as inflation), physicists are trying to build lower energy versions in order to make progress. “Under the new hypothesis, however, this strategy does not work because when we use it to model inflation, the inflation process is so fast that it subjects the sub-Planck regime to macroscopic observation,” the authors of the new study write.
Another possible approach to modeling the early universe lies in string theorywhich in itself is encouraginga candidate for the creation of a unified theory of everything (combining classical and quantum physics). Interestingly, in this model, the universe is not subject to a period of rapid inflation. Instead, the period of inflation is much milder and slower, and fluctuations are not "affected" by the macroscopic universe. However, the so-called "effective field theory" (string gas models) do not yet have sufficient detail to be verified on the basis of observable evidence of inflation in the Universe.
See also: Is the world really on the verge of discovering "new physics"?
Let me remind you that string theory predicts a hugethe number of potential universes, of which our specific space (with its set of forces and particles and the rest of physics) represents only one. Yet most (if not all) inflation models are incompatible with string theory at a basic level. Instead, they belong to what physicists call "swamps" - regions of possible universes that simply cannot physically exist.
Scientists today are still hoping to build a traditional model of inflation, but if the new hypothesis is correct, it will severely limit the types of models that physicists can build. It is also important to understand that the new hypothesis is so far nothing more than an assumption... Which, however, agrees with the unproven string theory (in fact, string theory is far from complete and is not yet capable of making predictions).
Interesting: New Proof of String Theory Discovered
But such ideas are still useful, becausephysicists fundamentally do not understand the inflation process. So anything that can help researchers hone their thinking skills, including outside the box, is welcome. Do you think physicists will be able to understand how the universe was born in the coming years? We will wait for the answer here, as well as in the comments in this article.