13.8 billion years ago, the universe was a singularity - space infinitely compressed by high pressure. However, in less than one fraction of a billionth of a second, this tiny dot expanded to an incredible size. The classical history of our universe has a beginning, a middle and an end. So, according to the general theory of relativity (GR) by Albert Einstein, the expansion of the Universe should slow down over time. However, reality paints a completely different picture: the universe continues to expand faster and faster. Scientists believe the reason for this discrepancy is mysterious dark energy, but it is possible that our understanding of the universe and its evolution needs to be revised.
There are many assumptions about how our universe originated and why it exists.
How did it all start and could it be otherwise?
The universe began to expand immediately after the Big Bang. The expansion rate at the early stage of its evolution - this process is called cosmological inflation - was significantly higher than after the end of inflation. So, gradually the Universe expanded and cooled, but only with a fraction of the initial speed. For the next 380,000 years, the universe was so dense that space was an opaque, super-hot plasma of scattered particles. When the universe cooled enough for the first hydrogen atoms to form, it became transparent for light to pass through. Then radiation erupted in all directions and the universe was on its way to becoming what we see it today - empty space that alternates with clumps of gas and dust, stars, galaxies, black holes and other forms of matter and energy. Finally,according to some models, all the clumps of matter will spread so far apart that they will gradually disappear. The universe will become a cold, homogeneous soup of isolated photons. But what if the Big Bang wasn't the beginning of it all?
The Big Bang theory is so widely accepted that sometimes you can forget that this is just a theory that has flaws. It is for this reason that scientists offer a variety of options for the development of events. For example, it has been suggested that the Big Bang may have been more of a "Big Bounce" - a turning point in the ongoing cycle of contraction and expansion of the universe. Another assumption is that the Big Bang became a reflection point, when the mirror image of our Universe expands beyond the “other side”, in which antimatter replaces matter, and time itself flows in the opposite direction. According to the third assumption, the Big Bang is a transition point in the universe that has always existed and will continue to expand indefinitely. All these theories are outside of mainstream cosmology,but they all found support among respected scientists. The growing number of new, competing theories suggests that it may be time to rethink the very fact that the Big Bang marks the beginning of space and time.
The universe we currently see is composed of clusters of gas and dust, stars, black holes, and galaxies.
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What if the Big Bang didn't really happen?
In academic circles, the idea has been repeatedly expressed that the Big Bang … did not exist. So, Eric Lerner, the author of the book of the same name, which he wrote back in 1992, presented the results of the study, according to which, according to the Invers edition, there is a discrepancy between the Big Bang theory and the observed factual data. "For the development of cosmology, it is necessary to abandon the main hypothesis of the Big Bang," - said in a statement Lerner. "The real crisis in cosmology is that there never was a Big Bang."
We are talking about the inconsistency of evidence for the presence of lithium in space, which astronomers, according to Lerner, have long been known. Scientists today believe that the exact amounts of helium, deuterium and lithium were produced by fusion reactions in a dense, very hot cloud of chemical elements that appeared after the Big Bang. However, Lerner, who has spent decades observing such reactions in detail, says that his and other scientists' findings do not coincide with long-standing theories based on observations of older stars. He found that less than half the helium and less than one tenth of lithium are observed in old stars than predicted by the Big Bang nucleosynthesis theory, according to which a quarter of the entire mass of the universe is helium. Lerner is convinced that neither lithium nor helium was created before the first stars appeared in our galaxy.
Could our Universe have arisen from nothing?
However, not all scientists agree with Lerner's theory. According to Vae Perumyan, professor of astronomy at the University of Southern California, Lerner rarely cites peer-reviewed articles, and many of his arguments do not hold water. For example, Perumian believes that microwave cosmic background radiation (or relic radiation), which indicates radiation emanating from the Big Bang, is a pillar of cosmological theory, which Lerner cannot dispute. Moreover, if there were such serious flaws in the Big Bang theory, Lerner would not have been the only critic of this theory.
But Lerner is not alone. Nobel laureate cosmologist James Peebles believes it is necessary to stop calling the earliest moments of our universe the "Big Bang". According to Agence France Presse, Peebles believes that there is no good way to check whether an event such as the Big Bang really took place - cosmologists have evidence of rapid outward expansion, but nothing is more discrete than a singular point that exploded to create everything in The universe. Peebles has no alternative to the Big Bang theory, but he is convinced that without sufficient data, scientists should not assume that this convenient hypothesis is correct. At the same time, the scientist admits that in the absence of a better way to describe the beginning of the universe, the Big Bang works great. In his calculations, Peebles also adheres to the generally accepted theory, although he really does not like it.
The Big Bounce: Can the Universe Expand Infinitely?
The most common Big Bounce hypothesis in academia is rooted in discontent with the idea of cosmological inflation. Cosmic microwave background radiation has been a fundamental factor in every model of the universe since it was first discovered in 1965. Moreover, the CMB is the main source of information about what the early universe looked like and at the same time a mystery to physicists. The fact is that the relic radiation looks the same even in regions that, it would seem, could never interact with each other in the entire history of the Universe.
The scars left by the Big Bang in the faint relic radiation that pervades the entire cosmos provide clues about what the early universe looked like.
According to the Big Bounce hypothesis, the universe will expand until it decays to one infinitesimal point - a cycle that lasts forever. In 2007, Martin Bojald, a physicist at the University of Pennsylvania, based on Einstein's model, put forward the theory of Loop quantum gravity - a field of quantum physics that describes the extremely high energies that dominated the early universe. Thus, the researchers concluded that the universe did not arise from nothing. and will not expand indefinitely. However, Bozhawald's research shows that the hypothetical previous universe was not exactly the same as ours. Overall, the Big Rebound hypothesis is consistent with the Big Bang picture of a hot, dense universe that began 13.8 billion years ago and began to expand and cool. But instead ofto become the beginning of space and time, the big bang was the moment of the transition of the universe from an earlier phase of existence, during which space was contracting.
However, critics believe there is little evidence to support this theory. For example, Peter Voight, a mathematician at Columbia University, wrote on his blog Not Even Wrong: "To be considered a legitimate theory, such claims must be supported by evidence."
Seeking Answers: All Paths Lead To Dark Energy
Proceeding from the fact that the generally accepted theory of the appearance and evolution of the Universe is the Big Bang theory, scientists are trying to find an answer to the question of why the Universe is expanding with acceleration.
Dark matter and dark energy are probably the keys to understanding our universe.
As the researchers analyzed the movement of stars and galaxies, they concluded that there were invisible particles, which they called dark matter. And the constant acceleration of the expansion of the Universe (the Hubble constant), suggested that it was caused by a certain phenomenon, which the researchers called dark energy. Dark energy and dark matter are the main scientific mysteries of our time, so researchers from the international group for the study of dark energy (DES) are looking for answers. DES started in 2004 and currently has 400 scientists from 26 different scientific institutions in seven countries participating in the project. Scientists are searching for dark energy using the most sensitive astronomical digital camera with a resolution of 570 megapixels. The camera is mounted on the Viktor Blanco telescope at the Cerro Toledo observatory in the Chilean Andes. It is a kind of scalpel equipped with five lenses.
Researchers believe that answers to fundamental questions about how the universe came into being and what dark matter and dark energy are should be presented to the general public in about five years. DES aims to analyze 100,000 galaxies that are up to 8 billion light-years away. Since dark energy cannot be seen, researchers measure the Hubble constant to determine exactly if dark energy exists and what it is made of. One way or another, we just have to wait for the results of the work of an international team of scientists and make assumptions about what our Universe is.
Lyubov Sokovikova