DARK MATTER AND DARK ENERGY-The unsolved mystery

DARK MATTER AND DARK ENERGY-The unsolved mystery

Our universe is a very mysterious and strange place. There are many theories that make us think that whether our universe is a place or not or even may exist or not in reality. Even many theories questioned the existence of our universe, they suggest that our universe may be a dream of a celestial Devin being or maybe a program of some intelligent beings. In Hindu recognition, it is believed that our universe is a dream of Lord VISHNU.

In the early 1990s, one thing was fairly certain about the expansion of the universe. It might have enough energy density to prevent its expansion and recollapse, it'd have so little energy density that it might never stop expanding, but gravity was certain to slow the expansion as time went on. Granted, the slowing had not been observed, but, theoretically, the universe had to slow. The universe is filled with matter and therefore the attraction of gravity pulls all matter together. Then came 1998 and therefore the Hubble Space Telescope (HST) observations of very distant supernovae that showed that, an extended time ago, the universe was actually expanding more slowly than it is today. So the expansion of the universe has not been slowing because of gravity, as everyone thought, it's been accelerating. No one expected this, nobody knew the way to explain it. But something was causing it.

In our universe, there are many mysterious places and objects that exist. One of them is Dark matter and dark energy. So let us try to understand the basics of it.

Our universe consists of 27% of dark matter, 68Úrk energy, and only 5% of visible matter.

Galaxies in our universe seem to be achieving an impossible feat. They are rotating with such speed that the gravity generated by their observable matter couldn't possibly hold them together; they ought to have torn themselves apart way back. The same is true of galaxies in clusters, which leads scientists to believe that something we cannot see is at work. They think something we've yet to detect directly is giving these galaxies extra mass, generating the additional gravity they have to remain intact. This strange and unknown matter was called “dark matter” since it's not visible.

DARK MATTER

Unlike normal matter, the substance doesn't interact with electromagnetic force. This means it doesn't absorb, reflect or emit light, making it extremely hard to identify. In fact, researchers are ready to infer the existence of substance only from the gravitational effect it seems to possess on visible matter. Dark matter seems to outweigh visible matter roughly six to at a minimum of one, making up about 27% of the universe. Here's a sobering fact: The matter we all know which makes up all stars and galaxies only accounts for five of the content of the universe! But what is dark matter? One idea is that it could contain "supersymmetric particles" – hypothesized particles that are partners to those already known within the Standard Model. Experiments at the  LHC may provide more direct clues about dark matter.

Many theories say the substance particles would be light enough to be produced at the LHC. If they were created at the LHC, they might escape through the detectors unnoticed. However, they might take away energy and momentum, so physicists could infer their existence from the quantity of energy and momentum “missing” after a collision. Dark matter candidates arise frequently in theories that suggest physics beyond the quality Model, like supersymmetry and additional dimensions. One theory suggests the existence of a “Hidden Valley”, a parallel world made from a substance having little or no in common with matter we all know. If one among these theories proved to be true, it could help scientists gain a far better understanding of the composition of our universe and, especially, how galaxies hold together.

DARK ENERGY

Dark energy makes up approximately 68% of the universe and appears to be related to the vacuum in space. It is distributed evenly throughout the universe, not only in space but also in time – in other words, its effect isn't diluted because the universe expands. The even distribution means dark energy doesn't have any local gravitational effects, but rather a worldwide effect on the universe as an entire. This leads to a repulsive force, which tends to accelerate the expansion of the universe. The rate of expansion and its acceleration is often measured by observations supported the Hubble's law. These measurements, alongside other scientific data, have confirmed the existence of dark energy and supply an estimate of just what proportion of this mysterious substance exists.

One explanation for dark energy is that it's a property of space. Albert Einstein was the primary person to understand that vacant space isn't nothing. Space has amazing properties, many of which are just starting to be understood. The first property that Einstein discovered is that it's possible for more room to return to existence. Then one version of Einstein's gravity theory, the version that contains a constant, makes a second prediction: "empty space" can possess its own energy. Because this energy may be a property of space itself, it might not be diluted as space expands. As more room comes into existence, more of this energy-of-space would seem. As a result, this type of energy would cause the universe to expand faster and faster. Unfortunately, nobody understands why the constant should even be there, much less why it might have precisely the right value to cause the observed acceleration of the universe. 

Helpful links 

• https://www.google.com/amp/s/www.space.com/amp/17661-theory-general-relativity.html
• https://www.google.com/amp/s/www.forbes.com/sites/startswithabang/2016/11/25/what-every-layperson-should-know-about-string-theory/amp/