Research

The mystery of the solar system: what causes anomalies in the orbits of trans-Neptunian objects

Somewhere on the far borders of the solar system, beyondNeptune's orbit, something strange is happening. Several small cosmic bodies demonstrate behavior that is not characteristic of the rest of the objects in our system, and scientists cannot understand the causes of the observed phenomenon. According to the most popular hypothesis, the Ninth Planet, a planetary object that scientists from around the world are looking for, can explain the statistical anomaly in the distribution of the orbits of isolated trans-Neptune objects (TNO). However, one group of physicists comes up with another, more logical, in their opinion, explanation of the observed effects.

Instead of one large object, the causeAstrophysicists Antranik Sefilyan from the University of Cambridge (United Kingdom) and Jihad Touma from the American University in Beirut (Lebanon) consider the observed orbital distortions to be the combined gravity of a group of small trans-Neptunian objects and Kuiper belt objects. A preprint of an article describing their findings has been published on the website of the electronic library arXiv.org and is being prepared for publication in the Astronomical Journal.

If this hypothesis seems familiar to you, sothis is because Sefilyan and Touma are not the first to speak with her. However, the mathematical calculations carried out by this pair of astrophysicists for the first time explain the existence of strange features in the orbits of trans-Neptune objects and take into account the presence of the remaining eight planets of the Solar System.

For the first time the assumption that in the Solarthe system may be another big planet, which was called the "ninth", was launched in 2016. Studying the behavior of one of the Kuiper belt dwarf planets, astronomers also found a strange orbital anomaly in some trans-Neptunian objects - they were “cut off” from the gravitational influence of the gas giants of the Solar System and had a strange orbit inclination that distinguishes them from other Kuiper belt objects. In addition, it was noted that six of these objects were grouped in such a way that it did not attract mere coincidence. The idea arose that someone “pushed” them or “pulled” in the same direction. According to computer models, this could make some kind of giant planet never before unseen.

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Scientists still can not find it. In general, this is understandable. According to the same assumption, the orbit of this planet is very elongated and can run very far from the Sun. It is quite difficult to search for an object in complete darkness, especially if you don’t know exactly where to look. At the same time, such elusiveness forces scientists to turn to alternative hypotheses, excluding the existence of the Ninth Planet, but at the same time trying to explain the strange behavior of some small space bodies on the far reaches of our solar system.

"The hypothesis of the" Ninth Planet "is certainly veryinteresting. Even if this planet exists, it seems that it is very active in “avoiding” its discovery, ”Sefilyan comments, adding that the team would like to look for a less pathetic explanation for the strange behavior of some TNO.

“We thought why instead of searching for the ninththe planet, and then attempts to explain its appearance and an unusual orbit, do not consider the possibility of the influence of gravity of more compact objects that form a belt beyond the orbit of Neptune, and then see where this all leads us. ”

Scientists have created a computer model of individual TNO,they included all the planets of the solar system, taking into account their gravity, and also took into account the presence of a huge Kuiper belt disk consisting of small bodies left after the formation of the solar system. By introducing data on the mass, eccentricity (an indicator of object deflection) and disk orientation into the model, the researchers were able to recreate cluster loop orbits of objects that stand out in reality against the rest of the TNO.

“If you remove the“ Ninth Planet ”from the model and insteadit allows for the presence of many small bodies scattered over a wide area, then the collective force of attraction of these objects is fully capable of explaining the eccentricity of the orbits that we see in some trans-Neptunian objects, ”Sefilyan explains.

Model Sefilyan and Touma solves the issue with whicha group of researchers from the University of Colorado at Boulder collided, also last year with the hypothesis of collective gravity. Their calculations also reflected the effect of gravitational effects on some trans-Neptunian objects, but then scientists could not explain why the orbits of these objects have the same slope.

And yet, both models have a flaw. To reproduce the observed effect of the orbital anomalies of some TNO, the Kuiper belt mass should be at least several terrestrial masses. According to the most recent calculations, the weight of the Kuiper belt is only from 4 to 10 percent of the earth.

At the same time, according to the formation patternsThe solar system, the mass of the Kuiper belt should be significantly higher. According to Sefilyan, the difference can be explained by the fact that it is impossible to calculate the exact belt mass due to our location, which does not allow seeing it in its entirety. It is quite possible, according to the scientist, the Kuiper belt contains many more objects, we are simply unable to see them.

"We have no overall picture of the belt, we also do not seedirect evidence of the presence of the “Ninth Planet”, therefore, consider alternatives. It is also impossible to exclude the possibility that both options may be correct - the Kuiper belt itself is much larger than we see it now, and the “Ninth Planet” actually exists. With each discovery of a new trans-Neptunian object with strange features, we get more and more information, which ultimately helps us find an explanation for their behavior, ”Sefilyan concludes.

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