Research, Technology

Does dark matter exist? And why are scientists divided?

Humanity can be called an ambitious species.We live on a small planet revolving around an ordinary star and yet we strive to unravel all the mysteries of the universe. Take, for example, dark matter. It is believed that it makes up most of the matter in galaxies, but it is impossible to observe it - this mysterious substance does not interact with electromagnetic radiation. We know about its supposed existence due to the gravitational effect it has on the objects we observe. Today, both dark matter and dark energy are the main pillars of the leading cosmological model. Recently, a study was published in the journal Astronomy and Astrophysics listing evidence for the existence of dark matter in the very first galaxies in the universe. But if scientists are wrong and no dark matter/energy actually exists, our ideas about the structure of the universe will have to be revised. And this, you see, is serious.

Today, physicists are increasingly moving away from idealized scenarios and are turning to complex realities.

Content

  • 1 The search for invisible matter
  • 2 Dark matter inside galaxies
  • 3 Dark matter alternative
  • 4 New dark matter detector

The search for invisible matter

In the 1970s, astronomers Vera Rubin and Kent Fordpresented a new theory capable of explaining the observed behavior of stars, planets and galaxies. They suggested that some invisible substance has a strong gravitational effect on visible celestial bodies. According to Rubin and Ford, this "dark matter" holds space objects together, as if gluing them together.

Researchers have also tried to understand whycelestial bodies located outside the center of the galaxy rotate at the same speed as objects near it. This state of affairs contradicts Newton's law, according to which stars and gas should slow down as they move away from the galactic center, but observations show that this is not the case, and the presence of mysterious matter can explain what is happening.

Maybe dark matter doesn't exist.

The theory of Ford and Rubin, however, did not receiveuniversal acceptance, and many researchers are still convinced that dark matter does not exist. NASA scientists are ready to argue with them - as the results of a new study show, there are a number of factors confirming the conclusions of the 1970s.

More on the topic: Can dark matter form from ordinary matter?

Dark matter inside galaxies

The presence of an invisible substance that "sticks together" stars and planets is changing our understanding of the universe. The fact is that observable matter in galaxies is only 20% – researchers call this matter baryonic (meaning that it consists of such subatomic particles as protons, neutrons and electrons). The remaining 80% remain invisible and incomprehensible.

Authors of a paper published in a scientific journalAstronomy and Astrophysics provide new evidence for the existence of dark matter. At least 260 young spiral galaxies in which new stars are being formed became the object of the study.

You have taken over the spiral galaxy NGC 986

Recall that the distance between our planet andselected objects is approximately seven billion light years. This means that they formed when the universe was twice as young as it is today (the age of the universe is approximately 13.8 billion years). These galaxies are shaped like the Milky Way, with its spiral arms of stars and gas clouds.

Read even more articles about the secrets of the Universe and dark matter on our channel Pulse Mail.ru So you definitely won't miss anything interesting!

Astronomers have been able to confirm that these younggalaxies are surrounded by a halo of dark matter emanating from the galactic center. These halos, however, are much more compact than those of the galaxies closest to us, which means that the distribution of dark matter within galaxies is slowly expanding over time.

We believe that this phenomenon illustrates a directinteraction between dark matter particles and ordinary baryonic particles: the halo density changes and goes beyond known gravitational interactions, the researchers write.

Dark matter can't be seen, but that doesn't mean it doesn't exist.

Astronomers also point out that dark matteris responsible not only for the large-scale structure of the Universe (details here), but also for clusters of galaxies held together. Did you know that dark matter can hide in an extra dimension? All details can be found here.

Dark matter alternative

Another group of researchers suggested thatthe situation around dark matter has changed - the answer should be sought in gravity itself. If you look closely at the universe full of galaxies, stars, dust, gas and black holes, you can find something already known. After all, if additional gravitational effects exist, something invisible could be responsible for them, for example, a fundamentally new type of matter or particles.

This is interesting: The quantum world: how are sterile neutrinos and dark matter related?

So, if neutrinos were massive enough,that might well explain what's going on. Another option could be the birth of a universe with too much matter, some of which collapsed to form black holes. Such options could put an end to the endless inconsistencies between the actual behavior of celestial objects and our physical theories.

dark matter is a hypothetical form of matter that makes up a quarter of the entire mass and energy of the universe.

Alas, these assumptions are unlikely to be true,since the total amount of baryonic matter in the universe is already known. Some researchers are also proposing to rethink the theory of gravity in order to completely get rid of the dark mother. But if we want to unravel the mysteries of the universe, dark matter (and energy) should not be abandoned, at least not yet.

Note that scientists often discover somethingnew, capable of challenging the prevailing theories. For example, the results of previous studies have shown that young star-forming galaxies seem to experience a deficit of dark matter (compared to later galaxies). For this reason, some physicists believe that dark matter plays a much smaller role in early star systems than in modern galaxies. However, to date these assumptions are not valid.

You will be interested: Dark matter - the key to the theory of gravity?

New dark matter detector

To find out if dark matter exists, scientistslong time to observe the galaxies. Fortunately, new astronomical instruments, including the James Webb Space Telescope, are able to "see" our universe's distant past, including the first stars and galaxies that formed shortly after the Big Bang.

As part of the Lux-Zeplin project, scientists will look for signs of the existence of matter inside a titanium tank filled with liquefied xenon.

Researchers have high hopes for the mostsensitive dark matter detector LUX-ZEPLIN, which is located 1.5 km underground and placed in a large tank of water (this is done to protect the LZ from collisions with other particles). As the name suggests, the detector is the successor to two previous projects, LUX and ZEPLIN, but its latest version is 50 times more sensitive to potential dark matter signals.

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Among the candidates for the role of dark matterresearchers identify weakly interacting massive particles (WIMPs) born in the early universe. If they really exist, then they interact with ordinary matter, creating already familiar astronomical anomalies. The new detector is surrounded by sensors that monitor any intrusion of the desired particles, and a reservoir of ultra-pure liquid xenon is used as a target.