Far behind the eight planets of the solar system, behind Pluto and dwarf planets, a gigantic new world may be hidden, which has so far been called the "ninth planet". There is hardly any other discovery that could be more sensational than the discovery of another planet orbiting our star. This planet has become the holy grail for astronomers, because such discoveries in the era of mankind did not happen so often. No one yet knows exactly where this ghostly world could be and if it exists at all. But in their search for a ninth planet, scientists have narrowed their search in half in just a few months. The chronicle continues.
In January, astrophysicists Konstantin Batygin and Michael Brown of the California Institute of Technology presented data pointing to a large undiscovered planet 9. Their computer models suggested that the gravitational pull of such a world could explain the strange misaligned orbits of several bodies in the Kuiper belt of ice objects. Scientists are now trying to find the planet using some of the largest telescopes on Earth, such as the Subaru telescope in Hawaii.
The work of Batygin and Brown narrowed the planet's possible mass and orbit to levels where previous observations might have missed it. Their calculations showed that the planet is 5-20 times heavier than the Earth - this is a key indicator indicating the approximate size of the desired object. They also suggest that the planet's orbit is tilted 30 degrees relative to the plane of the solar system - a relatively thin flat zone in which the orbits of eight major planets lie. Moreover, the planet is now, apparently, located at the farthest point from the Sun, in the northern hemisphere of the night sky, and its orbit is stretched 380-980 astronomical units (AU) from the Sun. One A. That is, it is equal to the average distance from the Earth to the Sun.
Yet these estimates still leave a strip of sky "1,500 square degrees in size," says astronomer Scott Sheppard of the Carnegie Institute of Science, who, along with astronomer Chadwick Trujillo, first suggested a ninth planet in 2014. (For comparison, the view of the full moon from Earth covers about 0.5 degrees of the sky.) This strip, described by Sheppard, corresponds to approximately 20 nights of Subaru observations. “And if we get seven nights this year, there will be three years - not counting the rainy nights,” Sheppard says.
Thus, the strategy in this race at present is to reduce the search area by eliminating theoretical possibilities. In an as-yet-unpublished set of hundreds of new high-resolution computer models, Batygin says, he and Brown narrowed down planet 9 to 600-800 square degrees of sky. They first modeled a solar system 4 billion years old, focusing on how the gravitational pull of the largest planets in the system - Jupiter, Saturn, Uranus, Neptune, and planet nine - could have shaped the orbits of thousands of randomly scattered Kuiper belt objects.
“We're looking for all the effects that planet nine has on the solar system,” says Brown.
In an attempt to refine the probable orbit of the ninth planet, the researchers compared their results with the current appearance of the Kuiper belt. “Our work has produced a synthetic solar system that is very similar to the real one,” says Batygin. "My confidence in the existence of the ninth planet is almost at its maximum, given how close our results are to what we actually see in the solar system."
Other strategies include studying Planet Nine's own gravitational influence on other bodies. Astronomers Yuri Medvedev and Dmitry Vavilov of the Institute of Applied Astronomy of the Russian Academy of Sciences studied 768 comets that first entered the solar system, and noted five of them that could pass close to a new planet - so that its gravity would change their paths - once in the past. Their analysis showed that "the ninth planet may have caused these comets to enter the solar system," Vavilov said. "We think comets may narrow the location of planet nine." However, Sheppard warns us against using comets to search for the ninth planet, because besides this planet there may be many other forces that affect the orbits of comets."
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Analysis of Pluto by astrophysicists Matthew Holman and Matthew Payne of the Harvard-Smithsonian Center for Astrophysics has failed to find any convincing signs for or against Planet Nine. In part, this may be due to the poor quality of archived images of Pluto, from which it is difficult to understand whether Pluto's orbit could depend on the presence or absence of a ninth planet, Holman says. However, he notes that the high-quality data on Saturn from the ground-based network of radio telescopes that track the position of the Cassini spacecraft is very promising and is consistent with what Batygin and Brown reported.
Analyzing Mars' orbital changes could also help find a ninth planet, Holman says. Although it will have much less of an impact on Mars than Saturn - because Mars is closer and more closely related to the gravity of the Sun - there are many orbiters between Mars and Saturn and they have observed the Red Planet for longer, so their observations will simply be more accurate. In addition, the Cassini data allow you to estimate the distance with an accuracy of ten meters, and the data between the Earth and Mars are good in assessing the accuracy to a meter.
More potential information about the influence of the ninth planet can be found in how long it takes for the outer bodies of the solar system to complete their orbit around the sun. For example, the rotation of the four Kuiper belt objects with the longest known orbits is most easily explained by the presence of a ninth planet, says astronomer Renu Malhotra, head of the theoretical astrophysics department at Arizona State University in Tucson. The work of Malhotra and her colleagues also suggests two possible inclinations for the orbit of the ninth planet, one closer to the plane of the solar system at 18 degrees and another steeper at 48 degrees - this information can also help narrow the area of exploration.
Yet some studies limit possible locations to such an extent that they rule out the existence of a ninth planet altogether. For example, while previous research has shown that planet nine may exist because some of the orbits of Kuiper Belt objects come together, another explanation might be that we don't have many observations of this class of objects. This is the opinion of astrophysicists Corey Shankman of the University of Victoria and Samantha Lawler of the National Council for Resources of Canada.
Brown argues that he and Batygin took into account the possibility of bias in the observations, and also adds other lines of evidence to the reality of planet nine. For example, they found that the influence of this mysterious world could solve an old mystery about why the plane of the solar system is tilted in relation to the sun.
So far, everything converges to the fact that the orbits of distant objects in the Kuiper belt are difficult to explain by something else, if not the existence of the ninth planet. The number of weaves is crazy, says Malhotra. "It is surprising to me that the ninth planet has not yet been found."
ILYA KHEL
