What is the universe made of? Scientists have been looking for the answer to this question for decades, but only recently have they managed to get a little closer to the solution. Oddly enough, but 2020 turned out to be rich in scientific discoveries - for example, in September, astrophysicists discovered that matter makes up about 31% of the total amount of matter and energy in our Universe. The remaining 69%, according to scientists, is dark energy - a mysterious force believed to be responsible for the accelerating expansion of the universe. Following, in November, the work of a team of researchers from the French National Center for Scientific Research (CNRS) was published, according to which 40% of the visible matter in the Universe (which we did not know existed before) is hidden in the diffuse filaments of a giant space web connecting galaxies. We tell you what is known to modern science about the composition of the Universe.
French researchers suggest that because the filaments of the cosmic web are scattered and the signals they emit are weak, 40% of the matter in the universe went unnoticed for 20 years.
Baryons are particles made up of three quarks, such as protons and neutrons. They make up atoms and molecules, as well as all the structures that can be seen in the observable universe (stars, galaxies, galaxy clusters, etc.).
What is our Universe made of?
It is believed that the universe consists of three types of matter: normal matter, "dark matter" and "dark energy". Normal matter is made up of atoms, and stars, planets, people and all other visible objects in our Universe are made of them. As humiliating as it sounds, normal matter almost certainly makes up the smallest fraction of the universe, somewhere between 1% and 10%. According to the currently popular model of the Universe, 70% of matter is dark energy, 25% is dark matter and 5% is normal matter.
However, the results of a new study published in the journal Astronomy & Astrophysics suggest that about 40% of all visible matter in the universe - the one that makes up everything we can see and touch - has been discovered for the first time. A team of scientists from the French National Center for Scientific Research (CNRS) believes they have finally discovered it - hidden in the galactic filaments of the cosmic web.
Today, our knowledge of the Universe is not enough to say with certainty what it consists of.
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How much matter is there in the Universe?
Astrophysicists believe that about 40% of the ordinary matter of which stars, planets and galaxies are made went unnoticed (for 20 years), hidden in the form of hot gas in the networks of the cosmic web. Recall that the cosmic web consists of galaxies distributed throughout the Universe in the form of a complex network of nodes connected by threads, which, in turn, are separated by voids. Read more about what galactic threads and the cosmic web are in our material.
It is believed that the filaments of the cosmic web contain almost all the usual (so-called baryonic) matter in the Universe in the form of scattered hot gas. However, the signal emitted by this diffuse gas is so weak that in reality between 40% and 50% of the baryons go unnoticed.
These are the missing baryons, hidden in the filamentous structure of the cosmic web, and French researchers were trying to discover. They carried out a statistical analysis, during which they were able to detect for the first time X-rays from hot baryons in galactic filaments. The team used the spatial correlation between the position of the filaments and the associated X-rays to provide evidence for the presence of hot gas in the cosmic web and measure its temperature for the first time.
The cosmic web is a gigantic cluster of galaxies connected by voids.
The findings confirm earlier findings by the same research group, based on the indirect detection of hot gas in the cosmic web through its effect on cosmic background microwave radiation (relic radiation). The discovery could pave the way for more detailed studies using better data to test the evolution of gas in the filamentary structure of the cosmic web. In general, scientists still have a lot of work to do.
Perhaps we will never be able to unravel all the mysteries of the universe.
By the way, recently with the help of the X-ray observatory of the European Space Agency (ESA) XMM-Newton, astronomers showed that galaxy clusters in the distant universe are not similar to those we see today. They appear to be emitting more X-rays than scientists thought. It turned out that these galaxy clusters changed their appearance over time, and according to calculations, in the past there were fewer galaxy clusters in the Universe. But what does this mean?
Researchers believe that in this case, the universe must be a high-density environment, which is contrary to modern concepts. This conclusion is highly controversial, because there must be a lot of matter in the universe to explain these results - and this, as a result, leaves little room for dark energy. However, the results of French researchers have shown that these findings are not so contradictory. After all, if we couldn't make out baryonic matter in galactic filaments for 20 years, who knows how much more matter in the Universe we still can't see?
