From the very beginning of the existence of human curiosity, one of the most important questions that have been asked is what makes up everything around us. Philosophers of the Greeks began to interpret matter philosophically, so Aristotle (one of the great philosophers in his time) suggested that matter consists of fire, earth, water, and air. Moreover, as time went on Greek philosophers started to theorize that matter could be divided endlessly with enough energy, and some others, including Democritus, believed that matter consisted of a basic unit that he called the atom (in Greek, atoms). So through constant experiments across many generations regarding atoms, it slowly led to the discovery of many chemical elements such as iron, oxygen, and mercury. Which were called elements, they are basically substances that cannot be broken down further. Furthermore, Rutherford’s experiment led to the conclusion that all of these elements are made of atoms: a nucleus is made up of protons and neutrons around which electrons revolve. With the development of scientific instruments and the building of atomic accelerators in Geneva, we discovered that the sub-atomic particles that make up the nucleus are made of smaller particles called quarks. With all that combined, we discovered that all the substances that make up humans, animals, planets, stars, and galaxies consist of three quarks: the electron, one quark called up (Up Quark), and another called (Down Quark) that make up all the substances in the universe in addition to 13 other quarks. With additional research, we discovered that all matter and the rest of the quarks are less than 5% of the universe, while the other 95% of the universe consists of two things that we are far more ignorant of than we know of. 27% of the universe’s components are dark matter and 68% of the universe’s components are dark energy. In addition to the increasing unknown, there is no explanation for why quarks exist, except for the ones that make up the atom.
So how do we know that dark matter exists, and what is dark matter in the first place? When we contemplate the universe and follow the movement of galaxies and stars, we will notice peculiar behavior many times. Sometimes we would find a number of galaxies moving around each other, this phenomenon is called galaxy clusters. Galaxies consist of stars, planets, and cosmic dust which in turn builds up large amounts of mass, which means that they have tremendous gravity, and this makes the galaxies correlate with each other. However, if the movement of these galaxies in the cluster’s frame is checked, we will notice that they are moving at rapid speeds and in random movement, and this is not supposed to Gets.
Galaxies are huge masses, so they have huge gravity. So by the presence of matter in quantities that are proportional to the amount of gravity that makes these clusters coherent as they move faster. Therefore it is assumed that all of them will fly and scatter, in other words, if all the galaxies that form are combined together they Cluster. The gravity will not suffice to make these clusters coherent according to the theories of Einstein and Newton. So in theory there should be six times more gravity than was calculated to be a cluster.
This error has been confirmed on a smaller scale, such as with spinning galaxies. These galaxies are made of billions of stars orbiting each other at tremendous speed. The scientist (Jacobus Kapteyn) discovered it when he was studying this type of galaxy, he found out that the speed of the movement of the galaxy does not correspond to the number of stars inside the galaxy. In other words, when the scientist came after the stars to predict the speed of the galaxy, he found out that the movement of the galaxy is much greater than what was in his calculations, so the gravity that was calculated was not enough to hold this galaxy together. This is one of the biggest mysteries in astronomy today. How do clusters and rotating galaxies hold together without scattering their stars? What held it together? Is our understanding of gravity wrong, or is there a phenomenon or substance that we have not yet understood?
Einstein’s theories and Newton’s laws have many applications such as satellites, GPS, rockets, and other applications. Einstein’s theories and Newton’s laws are amongst the most scrutinized theories. Therefore, the matter of their error is extremely slim, so the most likely explanation is that there is a phenomenon that we have not yet begun to fathom.
Physicists and astronomers began to explain this phenomenon, but most of it, unfortunately, is difficult to verify, so it was excluded, in addition to excluding many theories such as “the cause of this gravity is a black hole” or “that there is an invisible cosmic cloud” or “that there are many planets and comets”.
After ruling out these theories, we will find ourselves heading to one possibility for this conundrum, which is that there is something invisible, that does not interact with anything, even light, and somehow has gravity. Researchers on this topic have called it dark matter.
So what do we know about dark matter? What we know now about dark matter is that it is approximately 27% of the universe and since it is invisible it does not interact with its surroundings and does not enter into any nuclear reaction. According to the Big Bang theory, after the explosion, there were a lot of hydrogen and helium nuclei (roughly for every 10 hydrogen nuclei, there is one helium nucleus). If dark matter entered into these reactions, according to complex calculations, it is assumed that the proportion of helium is much more than what is currently in our universe. Another explanation for that would be is that if dark matter merges with any ordinary matter, the chemical structure of the universe would be completely different from what it is now.
We conclude that dark matter is not a dark matter that floats in space, it is a strange substance that does not interact in any way with its surroundings. The only thing we know for sure is that it is 27% of the universe. Unfortunately, we now know only 5% of the visible universe with all these decades and centuries of scientific progress. This is frustrating for the scientific community, but studies and experiments are still oncoming to understand our world. Moreover, we must remember that the sole thing that drives us, is our curiosity for the world around us.