The Dark Energy and Dark Matter - What's Universe made of?

Have you ever looked up to the sky and wondered “What this vast and magnificent universe actually made of ?" Universe is such an amazing and illusive place keeping million and billions of year old secrets buried deep inside of it.

Video Credits: Kurzgesagt – In a Nutshell

When you talk about universe, everything matters. Not only the tiniest of tiny particle, but even the space that may appear absolutely empty to our eyes can hold such a vast mystery. It may take decades and decades for us humans to solve them. One such mystery that hasn’t been solved yet is THE DARK ENERGY AND DARK MATTER.

THE EXPANDING UNIVERSE:

Earlier it was a popular belief among the astronomers and cosmologists of the world that there are only attractive forces between two bodies in the world. They believed that 2 bodies can only attract each other until 1929. 

When Sir Edwin Powell Hubble observed the universe from his Hubble telescope in 1929 and saw that the galaxies he had observer earlier were now looking distant from each other. 

He made this remarkable discovery that the stars and galaxies are not moving away from each other on its own infect, it’s the universe that is expanding. This discovery blasted the world with new questions arising that if two bodies apply attractive forces on each other as explained by Einstein, than how can the stars and galaxies in the universe be going far from each other.

The Mystery:

This meant that there might exist some other dark mysterious repulsive energy in the universe that is pushing things far away from each other. Scientists believed this force to be repulsive is nature which cause the space and time fabric to stretch resulting in the universe to expand and making stars and galaxies and supernovas to expand far from each other. 

Because of the inability of understanding and detecting this energy, the astronomers named it THE DARK ENERGY.CAUSE OF DARK ENERGY: When Hubble observed the universe he saw the universe was not only just expanding, infect, it was accelerating. It has always been accelerating ever since the big bang but now it’s accelerating faster than ever. 

No one expected it; no one knew how to explain it. But one thing was sure that something was causing it. Even today more is unknown than known. All we know is that there is some strange repulsive force in the universe that is pushing everything away from each other.

Other than that, it is a complete mystery. Over the years theorists have come up with different ideas for the explanations of this mysterious force but none of them has been confirmed with a proof.

A little explanation:

One explanation is that dark energy might be a property of space. Einstein was the first one to conclude that empty space is not -nothing. It possesses some amazing properties, which are still not understood by the theorists even today. One such property is that even the empty space possesses its own energy. As space is everywhere, this energy has always been everywhere from the very beginning. 

According to Einstein, more space can come into existence and as more space comes into existence, more dark energy will come into existence. Since it is a property of space, it will not just disappear when more space comes into existence.

Many scientists believe that dark energy is there because of the cosmological constant that Einstein added in his theory of relativity to make his equation fit with the belief of static universe.

This cosmological constant is believed to be repulsive in nature that would send things far from each other otherwise because of attractive forces in the universe the universe will collapse.

Video Credits: TED

According to Einstein, the repulsive nature of this cosmological constant and the attractive forces between two bodies will cancel each other and thus supporting the idea of a static universe which neither expands nor contracts, staying still and never changing as believed by Einstein and as written in the holy Bible.

In 1929, when Hubble discovered the accelerating universe, Einstein’s idea of a static universe went flying out of the window. And the theorists called this cosmological constant his Biggest Blunder. No one understand as to why is cosmological constant should even be present there at the first place.

Alternate Idea:

According to another idea, Dark energy is the fifth and most unknown type of force in the universe. This idea comes from the concept of quantum matter according to which the entire universe if filled with a dynamic fluid which is responsible for the expansion of the universe. Scientists have named it ‘QUINTESSENCE’.

After all the failed attempts of explaining the mysterious energy, the last explanation of dark energy is that the Einstein’s theory of gravity is wrong. Which means we don’t even know how the gravity behaves?

The leading theory that the scientists today believe is that the space has energy possessing properties and dark energy is one of the property of space. Einstein’s cosmological constant (a repulsive force) might be responsible for the expansion of the universe.

This theory is the best fit for the explanation until and unless anew theory comes in to existence which not only defines the way the gravity works but also gives the explanation for the dark energy.

DARK MATTER:

The matter that we see in our everyday life is usually made up of baryon. That is why it is also called baryonic matter. But dark matter is something that unlike the dark energy is unknown and unexplained still up to date. Scientists call it dark matter because it is not made up of baryon and thus is not visible (meaning its dark).

If it was made of baryon then it would have been detectable because baryon has a property of absorbing radiation.

Dark matter is neither made up of antimatter. Because if it was, we would have been able to detect it by the unique gamma rays that antimatter produces. But dark matter is something which neither emits nor interacts with electromagnetic radiation and thus is invisible in the entire electromagnetic spectrum. 

The presence of dark matter hasn’t directly been observed but it’s still believed to exist because of the gravitational effects it has on the motion of visible matter, structure of the universe and other galaxies. There have been many claims of detecting dark matter but none were identified as dark matter.

Most commonly accepted theory is that dark matter is made up of non-baryonic weakly interactive massive particles (WIMS) which are ten to the power 100 times the mass of a proton but because of the weak gravitational interactive forces, are very hard or you can say nearly impossible to detect. 

According to the studies and available data the majority of the entire universe is made up of the DARK ENERGY and DARK MATTER.

Dark energy makes up 73% of the entire universe, which is a whole lot than expected. Dark matter makes up 23% of the entire universe. And the known matter which we are sure that exists makes up less than 5% of the universe which cannot even be considered, as less than 5% becomes almost negligible in such a vast and ever expanding universe. 

So basically, almost entire universe is made up of something that we don’t even know what actually is, that we can’t even detect or see, and we also don’t know if it even exist or not. Even if it does exist, then why is it present there at the first place and why is it expanding the universe away from us. 

The universe is a vast, deep and mysterious place that there are so many questions still to be answered and plenty more secrets yet to be un-ravelled!