Scientists around the world are actively working on the problems of astrophysics, discovering new data about space every day. However, some questions of the physics of the Universe still remain a mystery to be solved. Scientists are working on dozens of space physics problems using state-of-the-art equipment. But at the moment there is a list of 10 dark secrets of the Universe that scientists still have to decipher and, possibly, change the picture of the world.
1. Dark matter
In the 30s of the last century, astronomer Fritz Zwicky from Switzerland, during his research, came to the conclusion that the mass of a cluster of galaxies is greater than what is observed in them with telescopes. These observations indicated that there was something invisible in space, but with a certain mass. The unknown substance was called "dark matter".
Scientists have found that this substance is a quarter of all the matter in the universe. Until now, researchers are working to fix the interaction of particles of "close matter". The most incredible thing is to catch this phenomenon in the laboratory. Experiments of this kind are carried out in a deep mine, as it is necessary to reduce interference from cosmic rays.
"Dark matter" has such a property as mutual destruction, resulting in the formation of gamma radiation and the release of pairs of antiparticles and "normal" particles. Astrophysicists, using space and terrestrial devices, are trying to capture gamma signals, which are traces of dark matter.
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2. Stage of inflation of the Universe
According to the standard hypothesis, the universe began with inflation. At the time of its inception, it began to expand at a high speed, since it was affected by a certain physical field. But some astrophysicists concluded that such a stage did not exist. According to their theory, the universe was expanding at the same rate as it is now.
3. Dark energy
Scientists have found that the accelerated expansion of the Universe is associated with "dark energy", which makes up about 70% of the density of this substance. At the same time, physicists cannot give a clear definition of what it is and what properties this energy has.
The only way to study "dark energy" is to study the details of the evolution of the Universe in different epochs of its existence. According to one theory, inflation was followed by a period of slow expansion that lasted about 5-7 billion years. Deceleration was followed by acceleration, which can be observed even today. The laws governing the action of "dark energy" remain an open question.
4. The nature of black holes
Most scientists agree that black holes exist. However, their presence in the Universe is confirmed only by indirect experiments, since it is impossible to observe them. The fact is that black holes have no surface in the sense of the word in which we are used to. The limitation of their limits is called the event horizon, and what is beyond it is unknown. Neither radiation nor matter can escape from the inside of the black hole. Astrophysicists are working to prove the existence of this horizon.
5. Properties of the first stars and galaxies
Science knows what happened 300 thousand years after the Big Bang, but the history of the Universe has been studied unevenly. Hundreds of millions of years after this event, galaxies are gradually growing, but what processes preceded this is completely incomprehensible.
Scientists will have to deal with the issues of the birth of the first stars, after which they will be able to reveal the secret of the formation of supermassive black holes.
6. Where do ultrahigh-energy cosmic rays come from?
Nature has certain mechanisms with which you can accelerate particles to high energies. Every year, a particle with an energy that is a hundred million times greater than the energy of particles in the Large Hadron Collider flies from space to Earth, to an area the size of a large city.
Scientists have succeeded in proving that these particles arrive from regions of the Universe that lie outside our galaxy. At the moment, science does not know which objects are their sources, but it is possible that these are active galactic nuclei.
7. What is inside neutron stars?
Inside neutron stars is the densest matter in the universe. Thanks to gravity, after a supernova explosion, the stellar core contracts until it becomes a ball, the size of which is 20 kilometers in diameter, and the mass of the Sun. The density of this object is equal to the density of the atomic nucleus.
Scientists in the laboratory cannot achieve this state of matter. It was possible to establish that the ball exists in the form of neutrons, which can "survive" at such a temperature and density. That is why these stars were called neutron stars.
8. How do supernovae explode?
The cores of large stars, after exhausting the reserves of thermonuclear fuel, begin to rapidly contract. The existence of stars, which are about 10 times heavier than the Sun, ends in an explosion. After that, the peripheral regions lose their connection with the center and move away from it. During this, tremendous energy is released, reminiscent of a colossal flash. Astrophysicists call this phenomenon a supernova and want to understand in more detail the mechanism of action of this cataclysm.
9. "Pioneer anomaly"
Before launching satellites, scientists thoroughly calculate the trajectories and speeds of objects, taking into account the gravitational effects and the quirks of outer space. However, some satellites behave rather strangely. For example, the American spacecraft Pioneer 11 and Pioneer 10, which flew outside the solar system, slow down more than scientists calculated. Disputes about this phenomenon have been going on among astrophysicists for many years. Some researchers are convinced that they did not take into account the thermal radiation of the satellite itself.
10. How many terrestrial planets are there?
Astrophysicists have gone a long way in studying exoplanets orbiting other stars. In the near future, scientists will focus on finding terrestrial planets with an oxygen atmosphere and liquid water.
Irina Dobrova