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Universe: what is it, how did it originate and where are we?

The term “big bang,” also called “great expansion,” refers to the dominant idea in cosmological theory that the universe emerged from a single, unimaginably hot and dense point 13.7 billion years ago. This theory arose from the observation that other galaxies are moving away from ours at great speed and in all directions. And although most astronomers use this theory to explain how the universe began, what caused this expansion is still a mystery.

What is the Universe, how did it originate and where is our position?

According to NASA, “the universe is everything,” as it includes all of space and all of the matter and energy that space contains. This means that planets, moons, stars, asteroids and comets, and all the other things that astronomers cannot yet observe are part of the universe.

Therefore, the big bang was the moment the universe began, as a small, dense fireball that expanded. This did not happen in an already existing space, the big bang was the event that started the expansion and cooling of space itself.

When the universe was very young – about a hundredth of a billionth of a trillionth of a trillionth of a second – and still very compact – less than a billionth of the size of a single atom – it underwent incredible accelerated growth.

During this expansion, known as inflation, the universe grew exponentially and doubled in size at least 90 times. After inflation, the universe continued to expand, but at a much slower rate. In the beginning, in the first years after the big bang “explosion”, everything was made of gas. This gas, mainly hydrogen and helium, expanded and cooled.

Over billions of years, gravity caused gas and dust to form galaxies, stars and planets. Galaxies gathered into groups, clusters and superclusters. Some stars died in supernova explosions, whose chemical remains seeded new generations of stars and allowed rocky planets to form.

On at least one of these planets, life has evolved into consciousness. In other words, the matter that spread from the big bang became everything in the universe, including you.

Milky Way via Rawpixel

In short, Earth is in the Virgo supercluster – but that doesn’t answer the question, does it? Well, a supercluster is a group of galaxies held together by gravity, and within superclusters there are smaller groups of galaxies – and the group we’re in is called the Local Group.

Within this group lies the Milky Way, the second largest galaxy in the Local Group. In turn, the Earth is located in a solar system located in one of the spiral arms of the Milky Way, the Orion Arm, about two-thirds of the distance from the center of the galaxy.

Our solar system, estimated to have come into existence just over 9 billion years after the big bang, is a group of eight planets, plus several comets, asteroids, and dwarf planets that orbit the Sun. Earth is the third planet in the Solar System, apparently the perfect place for life to develop.

The post Universe: what is it, how did it originate and where are we? appeared first on Olhar Digital.

Source: Olhar Digital



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