? What happened before the Big Bang
Most physicists support the Big Bang Theory, which says that the universe 14 billion years ago was about a million billion billion times smaller than the atom. It has expanded since that moment to the size we see now, which includes more than 100 billion galaxies. But the question: What happened before the explosion?
We were certainly not in that era, but many theories have emerged that give a theoretical explanation for what might have happened. and the most important:
Being out of nowhere
This idea assumes that the universe and time did not exist before the Big Bang, so that there was no creation, that is, our universe came out of nothing, as Stephen Hawking puts it, “There was no creation or destruction, it just exists.”
The first to come up with this idea was the physicist and quantum cosmologist Alexander Vilenkin, a professor at Tufts University. Which explained the emergence of the universe out of nowhere by relying on a phenomenon known as quantum tunneling, which allows a particle much smaller than an atom - which corresponds to the size of the universe at the first moment of the explosion - to exist in more than one place at a time.
If our universe was a particle swimming in a foggy quantum world. Which led Hawking to develop a theory that gives an explanation of how the universe can create itself based on the laws of quantum mechanics alone, regardless of the initial conditions or anything outside the universe itself, that is, without the need for the existence of a Creator.
Being from a black hole
A black hole is a dead star that has a massive gravitational pull, as its gravitational pull is so strong that light cannot escape from it. This idea says that our universe started from a black hole of a previous universe, that is, there was a universe and then ended up in a black hole, and from here the beginning of our universe and everything in it.
That is, every black hole may have a universe inside, of course, we don't yet have the ability to know that, but if the idea is correct, then the matter that formed our universe may have come from somewhere else (it was swallowed up by the hole in which our universe was created). As a result, the universe we live in is inside a hole, inside another universe.
parallel universes
Another idea that has emerged from superstring theory, is called parallel universes. It was developed by Paul Steinhardt and Neil Turok at the Perimeter Institute for Theoretical Physicists in Canada.
The idea came from the possibility that our universe has many dimensions, more than just three spatial and temporal dimensions. As we know, there are three spatial dimensions of space, but the theory predicts the existence of additional dimensions as well, but they coil on themselves in a way that we cannot notice.
Physicist Brian Greene at Columbia University explained the idea: “It is possible that our universe is one of many universes floating in multidimensional space, like a piece of bread from a great cosmic loaf.” In addition to these universes not always parallel, it is possible for two universes to collide violently, causing Big Bangs over and over again.
Two-Headed Time Theory
Two-Headed Time Theory, developed by Sean Carroll, Professor of Physics at the California Institute of Technology, and one of the few physicists who are called quantum cosmologists. His theory states that the Big Bang is what It is nothing but an event in an endless chain of time, where time exists and is infinite. Unlike Aristotle, Newton and Einstein who imagined a static universe, the universe according to this theory is created and annihilated ages ago.
That is, the behavior of the universe before the Big Bang is almost a mirror image of its behavior after the Big Bang. As if time moves backward for billions of years - as the universe shrinks - until it shrinks to a subatomic size, then the explosion occurs and time begins, and the universe expands in the way we see it now, and this behavior is returned to infinity.
All these ideas remain just possibilities to explain the origin of the universe, while physicists expect that within the next 50 years, we may get answers through many modern theories, such as superstring theory.
Sources:
insidescience site
harpers website
space . site
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