There is no person who does not admire the sky strewn with stars. And everyone probably thought about the question "did the universe have a beginning?"
D. Blok, professor of astronomy says: "The idea that once the universe did not exist has always been taken with hostility." But in recent decades, enough evidence has emerged to believe that the universe had a beginning. Today, almost all scientists come to the conclusion that the universe appeared due to an explosion, after which matter began to spread in different directions.
What led scientists to this conclusion?
Einstein's theory that the universe was either expanding or contracting was contrary to the generally accepted theory of the stationary universe at the time.
Einstein introduced into his calculations a quantity that he called the "cosmological constant." By this he tried to reconcile his theory with what was then considered a scientific truth.
But already 4 years later, Einstein had accumulated enough evidence to recognize his amendment as "the greatest mistake." Such evidence emerged when a 100-inch telescope was installed at the astronomical observatory in California. Observations of the universe with this telescope have proven that it is indeed expanding.
Prior to that, it was possible to consider only a few stars of the Milky Way. There were also blurry spots known as nebulae, but mistaken for gassing. But with the help of this powerful telescope, it turned out that this is not gaseous matter, but galaxies like ours. Today, there are up to 125 billion galaxies, each containing billions of stars.
Then it turned out that these galaxies are moving away from us. And the further galaxies are, the faster they move away from us. The speed of removal of galaxies, scientists determine using a spectrograph. The light that comes from distant stars is passed through a prism and decomposed into different color components.
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Light from a receding object, red. It is called redshift. And the light from approaching objects is purple. Accordingly, it is called the violet shift. It was noticed that only with the exception of a few galaxies close to us, all others have a redshift. So it turned out that the galaxy is expanding, and according to certain laws. The expansion rate is determined by the degree of redshift of the spectrum.
If we consider the reverse process of expansion of our Universe, as if all this was filmed, then you can see how the Universe is not expanding, but contracting. And eventually, it would return to the starting point. From this we can safely conclude that once the universe had a beginning.
More recently, it was believed that the universe had no beginning. Freud Hoyle, for example, argued that if there were a "big bang", then he should have left his mark in the form of a kind of relic radiation. Later, scientists Arno Penzias and Robert Wilson discovered background radiation - reflections from a flash after the "big bang". It seemed that after that the Big Bang theory was proved.
But after this discovery, new questions began to arise. If the Big Bang theory is correct, then why are there no weak inhomogeneous distributions of this radiation? For galaxies to form, colder and denser zones were required where matter could contract. But experiments made by astronomers did not reveal such irregularities.
Later, when the satellite was launched, the discoveries made by it became historical. It turned out that the small swell was the heterogeneity that remained in space after the Big Bang.
The fact that the universe had a beginning speaks in favor of the fact that it was created. Scientist Penzias, who participated in the discovery of background radiation, concludes that these discoveries lead to a unique conclusion: the universe was created from nothing. And George Smoot, who leads the group, said, "We've found evidence of the universe." He also added that witnessing such discoveries is like seeing God.
And yet, not all scientists admit that the universe had a beginning, or moment of creation. They are struggling to find alternative theories of the universe.