Mystery of the ninth planet: scientists are getting closer to discovery

Far beyond the eight planets of the solar system, even beyond Pluto and miniature dwarf planets, a significant new world may be hiding, called the "ninth planet." Few discoveries can be as sensational as another planet in orbit around the sun, which is why this topic serves as the Holy Grail for astronomers - and over the course of several centuries they managed to make such a discovery just a few times. So far, no one knows where this ephemeral world can be located, or even whether it actually exists. But in the discovery race, researchers are narrowing down their search space based on the influence of the celestial body on the solar system, and the area of ​​space where the planet should be searched has been reduced by about half compared to the state that was a few months ago.

In January, California Institute of Technology astrophysicists Konstantin Batygin and Michael Brown showed evidence of the existence of a large undiscovered ninth planet. From their computer models it follows that the gravitational action of this planet can explain the strange, inclined orbits of several objects from the Kuiper belt - a set of ice objects that inhabit the far reaches of the solar system. Scientists are fighting for the right to be the first to discover the ninth planet using Earth’s largest telescopes, such as the Subaru telescope in Hawaii.

Batygin and Brown set limitson the possible mass of the planet and the location of its orbit - where previous observations could miss it. According to their calculations, its mass is from 5 to 20 terrestrial - which is critical for understanding the approximate dimensions of a wanted object. They also believe that its orbit is inclined 30 degrees to the plane of the solar system - a relatively thin and flat zone in which eight major planets rotate. They also suggest that now the planet is farthest from the Sun, in the northern hemisphere of the sky, and the radius of its elongated orbit is on average between 380 and 980 AU.

But these estimates still capture an “about 1,500 square degree” sky sector, according to astronomer Scott Sheppard of the Carnegie Institute of Science, along with astronomer Chadwick Trujillo who suggested the existence of a ninth planet in 2014. For comparison, the full moon takes 0.2 square degrees of the night sky. The sky coverage described by Sheppard corresponds to about 20 night observations with the Subaru telescope, “and getting access to it for seven nights a year, it turns out that you need to wait three years - and then, if it does not rain,” says Sheppard.

The strategy of the race is to reduce the search area by eliminating theoretical possibilities. In a yet-published set of 100 high-resolution computer simulations, according to Batygin, he and Brown reduced the search for the ninth planet to a piece of the sky measuring 600-800 square degrees. First, they built a model for the evolution of the solar system over 4 billion years, focusing on how the gravity of the largest planets - Jupiter, Saturn, Uranus, Neptune and the Ninth Planet - could build the orbits of thousands of random objects of the Kuiper Belt (OPK). “We are looking for everything that the ninth planet does with the solar system,” says Brown.

In an attempt to clarify the probable orbit of the planet, the researchers compared the simulation results with the actual state of the Kuiper belt. “Our work showed a synthetic solar system that looks a lot like the real one,” says Batygin. “My confidence that the Ninth Planet exists has almost taken shape - after all, the results of the calculations coincide so well with the observations.”

Further strategies include investigating the possible gravitational effects of the ninth planet on other celestial bodies. Astronomers Yuri Medvedev and Dmitry Vavilov from the Institute of Applied Astronomy of the Russian Academy of Sciences studied 768 comets entering the Solar System for the first time, noting that five of them could come close to the ninth planet in the past, and as a result of its attraction change their course. Their analysissuggests that "the ninth planet could draw these comets into the solar system," says Vavilov. “We think comets can help narrow the field to search for the ninth planet. The discovery of additional comets would also help. ” Sheppard warns that it is necessary “to use comets with caution to search for the ninth planet, since many forces can influence their orbits. But despite my skepticism, it can help. ” Pluto

Analysiscarried out by astrophysicists Matthew Holman and Matthew Payne [Matthew Holman and Matthew Payne] of their Harvard-Smithsonian astrophysical center did not find evidence for or against the existence of the ninth planet. In particular, this was due to bad old archival photographs of Pluto, Holman says, making it difficult to see if Pluto was moving in orbit in a way that could confirm the presence or absence of a ninth planet. But he claims that the high-quality data on Saturn obtained from the ground-based network of radio telescopes that monitor the Cassini spacecraft are promising, and coincide with the calculations of Batygin and Brown.

Also, according to Holman, an analysis of changes in the orbit of Mars can help in the search for the ninth planet. Although the planet should have less influence on Mars than on Saturn - since Mars is closer to the Sun and is more strongly associated with it, there are more gravitationally artificial satellites in Mars, and they observe the Red Planet longer, so “their observations are much more accurate,” says Holman. In addition, "Cassini provides data with an accuracy of tens of meters, and the distances between the Earth and Mars are measured with an accuracy of meters."

Stronger evidence of the influence of the ninth planet can be found in the duration of the revolution of the remaining bodies around the Sun. For example, four OPK with the longest orbits circulate according to the schemewhich is easily explained by the presence of the ninth planet, as astronomer Renu Malhotra, director of theoretical astrophysics at the University of Arizona at Tucson, says. Her work with two colleagues hints at the presence of two probable inclinations of the orbit of the ninth planet, one closer to the plane of the solar system by 18 degrees, and the other steeper by 48 degrees. This information can help reduce a huge search area.

Some studies limit the possible location of the ninth planet so much that they can completely exclude the fact of its existence. For example, although previous studies suggest its existence due to the congestion of the orbits of certain DICs, observation of a limited number of DICs can only give the impression of a grouping of some orbits, as the astrophysicist at least says.Cory Shankman [Cory Shankman] from the University of them. Victoria and Samantha Lauler of the State Research Commission of Canada.

Brown argues that he and Batygin took into account the possibility of such observational deviations - and that other evidence also confirms the existence of the ninth planet. For example, Brown and colleagues found that the influence of this elusive world can solve the long-standing mystery of why the plane of the solar system is tilted with respect to the sun.

Malhotra from Arizona University says she is skeptical about the possibility of the planet’s existence, but notes that she and her colleagues found a tilt of the orbits of very distant DIC that is difficult to explain with other factors. “The degree of deformation is simply unrealistic,” she says. “As for me, this is the most intriguing proof of the existence of the ninth planet, of all that I saw.”