The problem was first detected in 1937. Swiss-American astrophysicist Fritz Zwicki introduced us to the 'missing mass problem'. Gentleman was observing the motions of galaxies in a large cluster (made up of many galaxies or galaxies together). This cluster, far from the Milky Way, can be traced by following the constellation Coma Berneses. Hence it is named Coma cluster.
Thousands of galaxies orbit the center of the cluster in such a way that it looks like a swarm of bees rushing towards a hive. Using the motions of roughly a dozen galaxies, Zwicky discovered that the average motion of the galaxies was surprisingly high, calculating how much the gravitational field bound the entire cluster together! Since strong gravitational attraction can cause an object to accelerate, Juicy assumed a large number, assuming the mass of the Coma cluster as the reason behind this strong gravity.
To test its reality, Zwicky added the masses of all the visible galaxies in the cluster and found that, even with all the masses, there was not enough mass to create the gravity required for this high speed. As FitzZwicky observed this coma cluster, he realized that there was something wrong with mass; Zwicky's experiments showed that all of the galaxies in this cluster are moving faster than their release velocities.
In simple terms, the escape velocity is the velocity required to break the gravitational binding and leave the orbit in a straight line. According to the calculations, the entire cluster should have run in the other direction. After hundreds of millions of years have passed, There is no trace left that it ever existed at all. But the cluster is about ten billion years old and still alive! Thus was born the oldest unsolved mystery in the history of astrophysics.
A solution to this problem could not be found then. Meanwhile, other clusters discovered after Zwicky's work showed the same thing happening in them. Therefore, there is no way to conclude the incident by attributing the coma cluster as something strange. Where is the trouble? Is the theory of gravity miscalculating? But inside our solar system this theory is working properly! Einstein's general theory of relativity is a modified version of Newton's gravitation. Gravitational action can be explained using this theory for objects of large mass. The problem is that the strong gravity of the clusters has not yet reached such a magnitude that Einstein's theory for the gravitational force can be tested properly.
Finally, scientists thought of a possibility. Maybe the 'elusive mass' needed to bind the Coma Cluster galaxies really does exist. They are like, We don't have the technology to detect that. Maybe that's why they are still invisible to us. They are named 'dark matter'. This means that the clusters do not actually lack mass, but that there must be some matter that we have yet to discover. By then, scientists have pretty much accepted the existence of dark matter inside the cluster. Because, calculus says - whatever the thing is, there must be something here. Just like this, the problem came up again. In 1976, scientist Vera Rubin discovered a similar mass distribution within galaxies.
The speed at which the stars in a galaxy move in their orbits around the center of the galaxy should be greater the further away the star is from the center. Because, the farther the star is from the center, The more matter (other stars and gas clouds) between them to resist the pull of the gravitational force, the faster they can run. A few isolated gas clouds and bright stars can also be found outside the bright disk of the galaxy. They can be used as tracers to measure the gravitational field of most regions outside the galactic halo, regions where no visible mass can be found to add to the galaxy's total mass.
So, as these distant stars use up their kinetic energy to move further away from the center day by day, their 'centripetal velocity' should decrease by now. But Rubin saw that their centripetal velocity was still as strong as before. In this vast void of space—the regions farthest from the center of each galaxy—there is no visible mass, so to speak. For which the orbital velocity of these tracer stars can be so high. So, Rubin logically concluded, there must be some form of dark matter in the boundary regions where the visible region of the galaxy ends and begins. Thanks to Rubin's work, we now call these regions of each galaxy 'dark matter haloes'.
Like darkness under a lamp, this halo or cycle problem can also be seen right under our noses, in the Milky Way Galaxy. Galaxies, or clusters — The difference between the mass calculated from visible objects and the amount of mass required for the existing gravitational force ranges from a few times to hundreds of times in some cases. This amount varies from case to case across space-time, but the average difference is about a factor of 6 when considering the universe as a whole. that is, The gravitational force exerted by dark matter hidden in space is six times greater than that exerted by objects visible to us.
Let us think a little about the time after half a million or five hundred thousand years after the birth of the universe. In terms of 14 billion years, the universe has only passed the time it takes to blink an eye. The matter that was in the universe at that time, has just started to congeal like bubbles. Over time these bubbles will eventually become galaxies, clusters and superclusters. But within the next half million years the universe will have doubled in size, and will continue to grow every moment.
This means, in the universe at that time, there is a strange war going on between two forces: on the one hand, gravity wants to pull everything together, and on the other hand, the ever-expanding universe wants everything to move farther, farther away. If you do a little math, you will understand. Gravity created from the mass of ordinary matter alone could not have won this battle. Help to win, help from dark matter. And at that time, without the help of dark matter, we would have a universe in which no infrastructure or structure would exist. In fact, 'we would have', we would not have existed! Therefore, there would be no clusters or galaxies, planets, stars or people in that universe.
How much gravitational help from dark matter was needed for gravity created from ordinary matter? Six times the gravity created from ordinary matter! Remember, we calculated earlier, this is exactly how much gravity is available from dark matter in the current universe? This is not a coincidence at all. Yes, this analysis does not reveal what dark matter actually is. But it is clear that the effect of dark matter is 100% real. because, No matter how hard you try, you can't credit simple matter with winning that war of time. The Bengali word for 'dark matter' is 'guptavastu'.
From this one can feel the matter better. We don't know what it is, what it looks like, or how it works, but there must be something lurking. Its type or properties may be discovered in the future, it may even be known that matter is not matter at all (although, this mystery creates gravity. And as any science student knows, gravity is caused by mass). But, whatever it is, scientists are sure that there is something. Because matter is hidden, not yet detected, it is called dark matter (cont.). . From this one can feel the matter better. We don't know what it is, what it looks like, or how it works, but there must be something lurking. Its type or properties may be discovered in the future, it may even be known that matter is not matter at all (although, this mystery creates gravity.
And as any science student knows, gravity is caused by mass). But, whatever it is, scientists are sure that there is something. Because matter is hidden, not yet detected, it is called dark matter (cont.). . From this one can feel the matter better. We don't know what it is, what it looks like, or how it works, but there must be something lurking. Its type or properties may be discovered in the future, it may even be known that matter is not matter at all (although, this mystery creates gravity. And as any science student knows, gravity is caused by mass). But, whatever it is, scientists are sure that there is something. Because matter is hidden, not yet detected, it is called dark matter (cont.).
Gravitation is caused by mass). But, whatever it is, scientists are sure that there is something. Because matter is hidden, not yet detected, it is called dark matter (cont.). Gravitation is caused by mass). But, whatever it is, scientists are sure that there is something. Because matter is hidden, not yet detected, it is called dark matter
Considerable efforts to detect dark matter have been, and continue to be, for about three-quarters of the last hundred years. Now, particle physicists are pretty sure of one thing: dark matter contains as-yet-undiscovered particles that interact gravitationally with ordinary matter. In addition, they either do not interact with matter or light at all, and if they do, they do so very weakly. The world's largest particle accelerators are trying to produce dark matter particles by colliding different types of particles. Meanwhile, efforts are being made to detect dark matter particles indirectly in specially designed underground laboratories. If occult particles, like other particles, somehow make their way to Earth from space, then they should be detectable.
The reasons for setting up these laboratories underground, Ensuring that no cosmic particles we know of can fool dark matter particle detectors by masquerading as cryptic matter. The Earth's surface naturally provides this protection for laboratories. Yes, it may all be unnecessary trouble, at the end of the day none of it will be of any use. But, it is really necessary to think about the deceptive secret particles and have some mechanism to detect them. The best example of this is the neutrino. They interact very little with ordinary particles. Even so, after the construction of the Icecube Observatory, it was possible to identify them correctly. Details about this can be found here.
Dark matter particles may also be captured by such rare interactions. Or maybe the powerful nuclear force could manifest itself. By something other than the weak nuclear force or the electromagnetic force. These three forces and gravitation are the four fundamental forces of the universe through which all the particles we know interact with each other. That is, there are only two ways. To detect either dark matter particles, we first need to discover a new force or class of forces and understand how they control how dark matter particles interact; Or dark matter particles interact very, very weakly through ordinary forces, and we need to detect them as such.
However, the effects of dark matter are purely real. We just don't know what the thing is. Observations show that dark matter creates gravity, and its effects also affect ordinary matter as we know it. Well, that's it. After all these years, we haven't seen it doing anything else. Nor could I discover anything. The history of the universe is a history of about 14 billion years, the whole revolution of our knowledge and science has happened in the last two hundred years. For those who are reading this article and thinking, what do scientists know?!
Let me say for them, sitting in a small room in a corner of the world, we can calculate the motion and nature of the planets of the solar system. I can say with certainty how fast the galaxies or clusters are moving away from each other. I can say that the universe was born exactly 14 billion years ago! Even so, our spacecraft have crossed the boundaries of the solar system, hurtling through interstellar space. Yes, we don't know the nature of 5/6ths of the mass of the universe or much about them. But the mystery of 14 billion years of history vs. just two hundred years—what we know using only a 3-pound brain during that time. Isn't that enough to make us dream?
