This infinitely spread universe has many secrets hidden inside it. The more we are trying to know about it, the more new questions are being raised in front of us. Until now, we believed that matter in the universe exists only in the form of molecules, atoms, stars, galaxies, planets, trees, rocks and animals. Which we can clearly see, but it is not so. Actually the universe we see is only a small part of reality. You will be surprised to know that about 95% of this universe is made up of matter that we do not see.
According to astronomers,
25% of this universe is made up of dark matter, 69% is from dark energy and only
5% is from normal matter.
So what the hell is
Dark Matter and Dark Energy, we will know in today's episode. So let's start this episode of today.
By the early 1990s we knew that our universe was constantly expanding. Another thing we were sure about its spread was that either the energy density of this universe is so high that at one time it will stop spreading and it will settle back to a point or else its energy density is so low that it will always spread. Here you might be wondering what is this energy density. Energy density is the amount of energy that we can store in a substance or system. In simple words, if the energy density of a substance is high, it means that there is more energy stored in that substance. Meaning that they had estimated that either the universe would settle back in one point or it would continue to spread according to its energy density.
But according to theory, one thing was absolutely certain that gravity will slow down the speed of the spread of the universe with the passage of time. They believed this because they believed that this universe was made up of commonly visible substances and their gravity bound the entire universe. The
slowing of its outbreak was natural due to the
pull in gravity. But in
1998, the
Hubble Telescope photographed a
Supernova, which showed that the rate of spread of our universe was slower than it is in the past. This meant that the speed of its spread was
increasing rather than decreasing, which was contrary to the theory of astronomers of the time. Everyone knew that there is something that is happening but no one was able to explain it. Finally, to solve this problem, they imagined an energy that exists in the empty places of the universe and named it
Dark Energy. Dark energy is quite strange and mysterious. It is present everywhere around us. But we can neither measure it nor test it. But one can see its impact very clearly. Where there is free space in the universe, new
structures are happening every second. It seems as if dark energy is some kind of energy that can be ghosted inside an
empty space. Because empty spaces have more energy than everything else in the combined universe. There are many ideas on what dark energy can be. The first idea is that dark energy can be a
property of empty spaces in the universe.
Albert Einstein was the first person to say that empty spaces are just visually empty, but they have some amazing qualities.
The first quality that he spoke about was that empty space in the universe can be created by itself and its quantity can increase with the spread of the universe. In his Theory of Gravity, he referred to a
cosmological constant and told that empty places have an energy of their own. The more the empty space increases, the more this energy will also increase so that this universe will continue to spread. But at that time he could not explain what was the need of this
cosmological constant. Because of which his theory was rejected. Perhaps this cosmological constant is dark energy. The second idea is that this empty space is actually temporary and filled with
virtual particles. These particles continue to be self
appear and disappear back somewhere.
The energy located in these particles can be dark energy. But there is a problem here when the physicists tried to calculate how much energy such energy can provide to the empty space, their calculation proved wrong because it was
10th power 120 more than the actual dark energy. Therefore, dark energy still remains a mystery to us. The final thought is that Einstein's theory of gravity is wrong and we need to understand it again. We need a theory that can explain every quality of the universe. But what could be such a new theory. Till date, we have not only understood the behavior of
celestial bodies present in the universe due to Einstein's Theory of Gravity but have also found them correct. In such a situation, it is difficult to imagine a completely new theory. In such a situation, the mystery of dark energy does not seem to be smoldering at the moment. This is about dark energy. Now let's know about
Dark Matter.
Over the past few years, we have found from research that gravitational direct matter in the universe is not strong enough to make galaxies and other complex structures. If it were stronger, instead of galaxies, the stars would be scattered all over the universe, not their flocks. This means that there is some material that maintains the existence of galaxies in the universe. Because no such material is visible to us, it is named Dark Matter. But what exactly is this dark matter like. Unfortunately, we have not found any clue so that we can know what the dark matter is and how it works. Till now we only know that it definitely exists in the universe because it reacts with gravitational action.
According to
Albert Einstein's theory, large and heavy
celestial bodies such as black holes divert space and time and also
divert the direction of light. Dark matter in the universe are empty spaces that divert the direction of light, which indicates their presence. This process is called
Gravitational Lensing and it acts like a natural lens, allowing us to see distant galaxies.
Dark matter is probably a complex and
unique particle, which does not react with any kind of matter and light. We know that dark matter is not
anti-matter because antimatter reacts with normal substances to produce
gamma rays. We also know that dark matter is not made up of black holes(already have a episode on black holes) as it is present in large quantities. It is not even a
dark cloud made of ordinary materials, so what can it be made of? Most scientists believe that these may be made of
Non-Baryonic matter. The substances we know about till now, such as
electron, proton, neutrons all come in
Baryonic matter. This means that it can be made of such substances, about which we do not yet know. The discovery of such substances can take our science forward many times. According to scientists, the substance they is searching for is named
WIMPS i.e.
Weakly Interacting Massive Particles and their mass is
100 times more than the flesh of a proton.
But they do not react with ordinary substances, due to which it is quite difficult to detect them.
Neutralino is also a potential candidate that is slower than neutrons, but such particles have not been seen yet. Some scientists even believe that dark matter is such a group of galaxies, which are
invisible and there physics methods work differently. As I already mentioned, we have been able to gather very little information about Dark Energy and Dark Matter. Meaning that we still have many such questions that are yet to be answered. All the theories that we have about Dark Energy and Dark Matter are still only theories. Perhaps in the future we will be able to solve these clues.
That's all in today's episode. Hope you liked this episode. How did you like this episode? Please tell us through the comment. We will continue to bring you articles related to space, universe and science. So friends meet in another interesting episode till then Namaste.
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