Astronomy – How did the universe begin?

For hundreds of years, this question has been posed. There is an innate desire for us to want answers to the big questions. These will include…How did it all begin? Where did we come from? What are we doing here? Why is there a universe at all? How is it all going to end? These are all big questions and in this article I will attempt to give an insight as to where the truth may rest. So let’s look at the first question, “How did it all begin?”

    Many of you will already be saying it all started with the Big Bang and that the universe was once very small and after the Big Bang it became bigger. Well yes, the Big Bang is still accepted as playing an important part in the early stages of the universe and is one of the most popular theories among scientists at the present time. However, we first need to see what evidence there is to make us think that the universe was once small, very small. There was a clue to the answer in a previous article when I said that the universe is still expanding. If this is correct and our observations already confirm this to be case, then in the past, our universe must have been smaller. If we now trace back in time we can calculate the approximate age of the universe and to when it all began.

    The figure scientists have arrived at states that the universe is about 13.7 billion years old. Some other astronomers have put the date a little earlier, closer to 15 billion years. But whichever is right, it was a very long time ago.

Photo by Pixabay on Pexels.com

    However, there is another component to the expanding universe. If we assume that close to the beginning of the universe, all the matter within it, that is, the planets, stars and galaxies, were much more tightly packed together, then we can also assume that all of this matter would have been much, much hotter than it is now. This leads us to postulate that the universe did indeed start with a Big Bang. So approximately 13.7 billion years ago our theory says that all the matter in the universe was so compacted together that the forces involved caused it to expand in one massive event. All of the matter began spreading out and is still doing so.

    But don’t think that at the point of the Big Bang taking place, all of the matter in the universe was in the same state that we would recognise today. This is definitely not the case. So let’s look at the Big Bang theory in more detail and see how we believe the events unfolded which created the universe we know today.

    The Big Bang theory was pioneered by a Russian physicist named George Gamow in the 1950s. His work on thermonuclear reactions within stars guided him on to his theory of how the universe began. It is important to note that the Big Bang is still just a theory. But it is one that is accepted by many scientists as being the most likely way the universe began. It also fits in with most of the evidence we can observe today. So until a new theory takes over, we will follow the Big Bang to see how the universe evolved.

    At the very beginning there was nothing. No space, no matter and no time. Therefore if we ask the question of what came before the Big Bang, the answer is nothing because space and time did not exist. We cannot be much clearer on this point because we just don’t know. Some people will say that this is where God comes into the equation and others that there may be an answer somewhere in quantum physics; it is a personal choice and mine is towards the latter.

    There then appeared a point of singularity. Where this came from and how it happened, we don’t know and is open to speculation. But the singularity was very small; smaller in fact than one atom. And potentially, all the matter in the universe is packed into it. It sounds amazing and just a bit crazy doesn’t it?

    But there are ways that we can explain how this could happen. Albert Einstein in his paper on Special Relativity produced perhaps the most famous equation in science;-

E = mc2

…where E stands for energy, m for mass and c is the speed of light. Since the speed of light has a very high value, the squaring of this produces a very big number. So if we take a look at the equation, we can see that;-

1: energy and mass are interchangeable and

2: that even a small amount of mass can produce a huge amount of energy.

   Earlier on we said that all the matter or mass in the universe was packed into a tiny primeval atom. In fact this speck would have been filled with energy and not matter. And this is where it gets even more amazing.

    After a tiny fraction of a second and we are talking less than trillionths of a second, the speck that is the singularity begins to expand. At the very start of this expansion our laws of physics do not operate. The singularity contains no mass but infinite energy. And energy does not take up as much room as matter. In fact all types of matter we encounter is mainly made up of empty space. Atoms are made up of a tiny nucleus with a lot of space around it in which electrons exist. But most of the space within an atom is empty.

    However, the moment it begins to expand we are able to apply our laws of physics and we can begin to understand what is going on. Now it only takes another infinitesimal period of time since the “birth” of the universe for another amazing thing to happen. But to give you an idea of the small timescales involved, this next phase occurred about 10-35 seconds after the universe begins. This number is 1 divided by 1 with 35 zeros after it.

    And what happened at this point is called inflation. The universe suddenly expanded or inflated at an unbelievable rate. In a tiny fraction of a second the universe expanded. We’re not too sure exactly how big, but the change in size was staggering. To be able to grow this fast means that the speed of light had to have been exceeded. Now as most people know, the speed of light is believed to be impossible to break. However, what is happening here is different from what we might expect. Objects “flying” through space cannot exceed the speed of light but during this inflation phase, all the energy was not expanding. It was space itself that was expanding and that is allowed to break the speed of light.

    Let’s skip forward in time to when the universe is 1 second old. I did say that the time scales were small. Because of the expansion it had begun to cool down. The “stuff” that constituted the universe at this point was a form of plasma. But now that the temperature had dropped other particles including protons and neutrons began to form out of the plasma.

    There are also other particles formed at this time and many people may think that they only exist in science fiction books. Antimatter is created in the same proportion as the newly formed matter. Now when matter and antimatter meet, they destroy each other and release a lot of energy. So now we have the young universe destroying itself. However, if the proportion of matter and antimatter were exactly equal, then all matter should have been annihilated. But it hasn’t been. Today, there is a lot of matter in the universe but very little antimatter that we can detect. This shouldn’t be the case and we cannot fully explain why. So this is how we currently believe the universe began. But the problem is that as we try to answer some of the most fundamental questions in the universe, we seem to end up with more just as difficult puzzles to solve.

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