What is dark matter? This phenomenon is explained simply

There is a very mysterious form of matter in our universe: we cannot see it because it does not glow or reflect light. That's why it's also called dark matter.

What is dark matter made of?

In contrast to visible matter, no one knows its composition; To this day, it is not entirely clear what kind of molecules they are composed of. While visible matter has condensed into stars and planets over billions of years, dark matter behaves very differently.

The mysterious particles that compose it do not form atoms, and therefore do not form more complex structures such as molecules. Although there are many projects around the world aiming to detect it, it has not yet been possible to detect even a single particle of dark matter directly using the detector.

Where is dark matter located in the universe?

Surprisingly, not a single dark matter particle has been discovered yet. Because: Dark matter exists everywhere in the universe, and it passes through the entire universe. It also exists here on earth; We are constantly permeated by it: foreign particles simply blow through us. We don't notice anything about him at all.

Because dark matter interacts very rarely with the atoms that make up our bodies. That's why we don't feel them. According to a popular theory, an average of about 100,000 dark matter particles rush through an area the size of a thumbnail every second.

How was the mysterious form of matter discovered?

Research into this mysterious phenomenon goes back a long way: as early as the 1930s, Swiss astrophysicist Fritz Zwicky postulated the existence of an invisible form of matter. The scientist noticed the speed of several distant galaxies forming what looked like a cluster. Based on complex calculations, Zwicky determined that the galaxies must be flying apart from each other.

If there was only visible matter, the mass of stars and the gas between them, galaxy clusters wouldn't be able to form at all – their gravitational pull simply wouldn't be strong enough to bind the stellar archipelagoes together. There must be more than just visible matter, something holding the galaxies together like a kind of glue. But Zwicky's theory was ridiculed by his colleagues and his discovery was ignored for a long time.

Only in the 1970s did American physicist Vera Rubin make another revolutionary observation that astrophysicists around the world took seriously: she determined the speed at which stars move around the center of the galaxy. He discovered that the difference in the speeds of stars can only be explained by the presence of a large, unknown mass.

What percentage of all matter is considered dark matter?

If there were only visible matter, then according to the laws of physics, stars far from the center of the galaxy should move much more slowly than they actually do. It has also been found that the dark matter surrounding galaxies deflects the light of distant celestial objects behind them through their enormous mass and the resulting gravitational force. The result: When viewed from Earth, objects beyond the galaxy appear distorted, as if they were being viewed through a lens.

There is further evidence of the existence of dark matter. There is radiation that fills the entire universe, and it comes from the earliest days of the universe and is a kind of echo of the Big Bang: cosmic background radiation. By measuring it precisely, one can calculate how much mass there actually was in the prehistory of the universe. These physical measurements reveal that the mass is much higher than that which makes up the world we can perceive – such as stars, planets, asteroids and gas clouds. You can also say: The universe has been weighed and it has been discovered that a large amount of matter is still missing. Which is: about 85 percent.

How did dark matter shape the universe?

Cosmologists assume that dark mass played a fundamental role in the evolution of space. It gave structure to the universe. Neither galaxies, nor galaxy clusters, nor the web-like connections of thousands of galaxy clusters can be explained without the power of dark matter.

With the help of modern computer simulations, physicists are now able to understand with complete precision the formation of structure and, in particular, the composition of galaxies in the universe. This simulation cannot work without dark matter.

How do you try to find the mysterious mass particles?

Physicists have been trying to obtain particles for decades. Using large particle accelerators such as CERN near Geneva, protons can collide at almost the speed of light. The collision creates many new molecules. The hope: There may also be a dark matter particle among these new particles (which can be identified through complex calculations).

Other researchers hypothesize that dark matter barely interacts with visible matter, but only roughly. It is assumed that very rare collisions can occur between two molecules. Because they are largely non-interactive, experts refer to hypothetical dark matter particles as “WIMPs,” which is English for “weak.” Meanwhile, WIMP is an abbreviation for “Weakly Interacting Massive Particle,” which is German for “Weakly Interacting Massive Particle.” If dark matter particles are indeed WIMPs, it might occasionally happen that such a weakly interacting particle collides with an atomic nucleus. A detector located in an underground laboratory in Italy's Gran Sasso mountain range, where Laura Bodis is conducting research, is based on precisely this assumption. It is the largest of its kind in the world.

Not a single particle of the matter that so densely permeates our universe has yet been discovered. But if so, it would be a scientific sensation. Among other things, the discovery of particles would pose enormous challenges to the Standard Model of particle physics, which describes the properties of the smallest building blocks of matter in our universe. So far, no dark matter particles have been included. The Standard Model refers only to particles of visible matter, and therefore must be expanded. This would be a major piece of knowledge in one of scientific mysteries.