11 mysteries about dark matter have not been answered yet

In 1930, a Swiss astronomer named Fritz Zwicky discovered that clusters of distant galaxies revolved around each other faster than the large galaxies they observed close by. He thinks this is an undiscovered form of matter, he calls it dark matter and they can have gravity hitting the galaxies.

Since then, researchers have confirmed that this mysterious material can be found throughout the universe, and that they are six times more massive than other types of matter that form stars or children. people. Even though we can see dark matter throughout the universe, scientists still have to scratch their heads every time they talk about them. Here are 11 questions about dark matter that are still unanswered:

1. What is dark matter?

Researchers have yet to confirm exactly what dark matter is.

This is the first and the most controversial question, so far researchers have not been able to confirm exactly what dark matter is. According to physicist Don Lincoln, from the US Department of Energy, at first, scientists surmised that the loss of mass occurred in space due to the small-sized off stars and black holes, however, there are currently no direct observations showing the effects of the two on dark matter. The leading recognized dark matter hypothesis is a particle called the Weakly Interacting Massive Particle, or WIMP, which, according to Lincoln, works like a neutron but has a heavier mass than a proton from 10. to 100 times.

2. Can we identify dark matter?

If dark matter is made up of WIMP particles, they will exist around us, they are completely invisible and hard to identify. So why haven't we found it for so long? Because they do not interact much with other matter, there is a small chance that when they travel in space, dark materials can hit a normal particle like an electron or a proton. Therefore, scientists have conducted many experiments to study large numbers of normal particles of matter underground to prevent radiation types to be able to catch the moment of collision of dark matter. . But the problem is that after decades, no sensor has been able to discover anything new. Earlier this year, the experiment of a Chinese company, PandaX, showed the latest report that WIMP does not exist. It seems that dark matter particles are much smaller than WIMP particles or lack of features that could make the research process easier, said physicist Hai-Bo Yu from the University of California.

3. Is there more than one type of dark matter particle?

Normal matter is made up of familiar particles like protons and electrons along with a strange forest of particles like neutrinos, muons and pions. Therefore, some researchers suspect that dark matter, which makes up 85% of the matter in the universe, could have such a complex structure."There is no good reason to believe that all the dark matter in the universe is made up of only one type of particle," said physicist Andrey Katz at Harvard University. Katz thinks that dark protons can combine with dark electrons to form dark atoms, thereby creating diverse and interesting structures in our tangible world. While in the physics lab, theories are appearing more and more, it is still far from finding a way to confirm or reject them.

4. Does dark force exist?

It is also possible that dark matter is subjected to forces similar to other matter.

Along with dark particles, it is also possible that dark matter is subjected to forces similar to other matter. Some scientists have searched for "dark photons," which can be like photons exchanged between normal particles and create electromagnetic forces, except that they will only be received by dark matter particles. Physicists in Italy are trying to shoot a beam of electrons and their antiparticles, called positrons , into a diamond. If dark photons do exist, then electron-positron pairs can destroy each other and create one of the strangest force-capable particles that could open up a whole new field in the universe.

5. Could dark matter be made of axions?

While physicists are increasingly away from WIMP, other dark matter particles are beginning to be concerned. One of the other theories is a hypothetical particle called axion , which would be extremely light, possibly 10 to 31 orders of magnitude lighter than protons. Several experiments are underway to search for axions. Recent computer simulations increase the possibility that axions can form objects similar to stars, which can emit detectable radiation, quite similar to a mysterious phenomenon. The hidden name is radio wave .

6. What are the properties of dark matter?

Astronomers have discovered dark matter through its gravitational interaction with ordinary matter. Show that this is exactly how dark matter manifests its presence in the universe. However, the more they tried to understand the true nature of dark matter, the researchers made little progress. According to some theories, dark matter particles must be their own antiparticles, meaning that two dark matter particles will destroy each other when they collide. Since 2011, experiments with the Alpha-AMS (Alpha Magnetic Spectrometer) from the International Space Station have been searching for signs of this decomposition and found hundreds of thousands of cases. Scientists are still not sure if these signals are coming from dark matter, and how that signal will help them clarify how dark matter is.

7. Does dark matter exist in all galaxies?

It seems that dark matter is not the condition required to form a galaxy.

Because of its overwhelming amount compared to ordinary matter, it is often thought that dark matter is the force that controls the formation of macroscopic structures like galaxies and galaxy clusters. But strangely, earlier this year, researchers announced they had found a galaxy, called NGC 1052-DF2 , that seemed to contain no dark matter. "It seems that dark matter is not the condition necessary to form a galaxy," said Pieter van Dokkum, at Yale University. However, after the summer, an independent research group published an analysis that Dokkum's group miscalculated the distance to that galaxy, meaning that its existing matter was much dimmer and much lighter. with initial results, and much of that galaxy's matter is dark matter rather than the previous result.

8. What about the results of the DAMA / LIBRA experiment?

A long-standing mystery in particle physics is the confusing results of an experiment in Europe called DAMA / LIBRA. The device - located in an underground mine beneath the Gran Sasso mountain range, Italy - is tasked with finding the periodic vibrations of dark matter particles. This periodic oscillation arises when the Earth moves in orbit around the Sun and flies through the stream of dark matter that surrounds our Solar System, sometimes called the dark matter wind. Since 1997, DAMA / LIBRA claims to have found this type of signal exactly, although no other experiment has found anything like it.

9. Can dark matter carry a charge?

A signal right from the start of the study led some physicists to suggest that dark matter could be charged. Radiation with a wavelength of 21 cm was emitted by stars in the universe, only 180 million years after the Big Bang. Then they were absorbed by low-temperature hydrogen gas that was ubiquitous at that time. When this radiation was discovered in February this year, it showed that the hydrogen gas was much lower than the scientists predicted. Astrophysicist Julian Munoz, at Harvard University, hypothesizes that dark matter carrying an electric charge can absorb heat from hydrogen gas, like ice cubes in a glass of lemonade. But his theory has not yet been accepted.

10. Can ordinary particles decay into dark matter?

Neutrons are a common type of particle because of their limited existence time. After about 14 and a half minutes, a single neutron released from the atom will decay into a proton, an electron and a neutrino. But different experimental arrangements will give the existence time before the disintegration of about 9 seconds, according to experiments cited in the journal Physical Review Letters. Earlier this year, physicists hypothesized that if within 1% of a neutron's lifetime, some neutrons could decay into dark matter particles, that would explain the difference. Christopher Morris at the Los Alamos National Laboratory in New Mexico and his teams track neutrons for signals of dark matter but cannot detect anything. They suggest that there may be other forms of decay.

11. Does dark matter really exist?

Dark matter is still an unverified structure.

With the difficulties scientists face trying to discover and explain dark matter, it is questionable whether they are on the right track. For a few years, a few physicists have mentioned the idea that maybe our theories about gravity are simply not right and gravity can have different effects on other large scale. Often referred to as "modified Newtonian dynamics ", or MONDs , these theories admit that there is no dark matter and the extremely fast rotation speed that stars and galaxies are the result of gravity. Works in strange ways . "Dark matter is still an unconfirmed structure," wrote physicist Don Lincoln in Live Science. But these scientists have yet to convince the general public of their hypotheses. And the latest evidence? They still hypothesize that dark matter is real.

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