What is the Planet 9 for a black hole primary? Here’s the way to find out


José Manuel NievesSEGUIRMadrid Updated: Save Send news by mail electrónicoTu name *

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Since several years, researchers around the world are trying, without success, to discover a new and huge planet hidden in the unknown outer regions of the Solar System. The calculations indicate that there, in some part, and to about 500 Astronomical Units (one AU equals 150 million km, the distance between the Earth and the Sun), there should be an object of between 5 and 10 land masses, a source of gravity that would explain the otherwise unexplainable orbits of several dwarf planets known in the Kuiper belt, a remote “dump” space filled with rocks that can exceed 1,000 km in diameter and home to many of the comets that we know of. The scientists named this mysterious world as “Planet 9”, but all of the efforts made until now to find him have proved useless.

For that reason, in 2019 Jakub Scholtz, of the University of Durham and James Unwin, of Chicago, published a study that suggested the disturbing possibility that, after all, the mysterious source of gravity is not a planet, but something far more intriguing, a black hole, primordial, impossible to detect with conventional methods.

According to the current theories, black holes, primordial should have been formed in enormous quantities during the Big Bang, and their range of sizes go from the microscopic (with masses of less than a kg), a few metres away, with masses similar to those of a star. What Per how to find something like that? By the time anyone has managed to see one.

A desperate search for

just a few weeks Ago, however, the astronomer from Princeton university Edward Witten suggested a method for doing so, launching a fleet of hundreds, or thousands of probes light (only 100 g each) where it is assumed that the tiny black hole should be. With luck, some of them could pass close enough to the black hole primary, so as to feel directly their severity, which would accelerate slightly. This acceleration could be measured from Earth and that would allow to locate the black hole.

Now, Amir Siraj and Abraham Loeb, the astronomers of Harvard University, have developed a new method to locate black holes in the outer Solar System, one that is not based on the release of thousands of probes but in the eruptions of material emitted by comets (very abundant in that region) that passed too near and were disturbed by the gravity of the black hole.

In a study that will appear soon in The Astrophysical Journal Letters and can be consulted on the server prepublicaciones ArXiv, the researchers suggest that the future telescope LSST (Legacy Survey of Space and Time), the implementation of which is planned for 2023, you will have the ability to find out, finally, if the alleged Planet 9 really is, or is not, a small black hole primary of just a few land masses.

“Near a black hole -explains Siraj – the small bodies that come to him are fused together as a result of the warming produced by the buildup of gas in the interstellar medium, which is attracted to the hole. Once they thaw, these small bodies are subject to the disruption of tide caused by the black hole”.

Loeb, for his part, adds that “because black holes are intrinsically dark, the radiation emitted by the matter in its path towards the mouth of the black hole is our only way to illuminate that dark environment”.

The researchers believe that their method could be applied to searches for black holes primordial in general. “This method -ensures Siraj – it is able to detect or rule out the existence of black holes of a planetary body on the edge of the Oort Cloud, up to about one hundred thousand Astronomical Units”. The study, however, focuses on the already famous Planet 9 as the first candidate to carry out this type of detection.

“The Planet 9 -continues Siraj – is a compelling explanation for the clustering observed in some objects beyond the orbit of Neptune. If the existence of the Planet 9 is confirmed through a direct search, will be the first detection of a new planet in the Solar System in centuries, not counting Pluto”. However, the null results of that search, “there has been much speculation about alternative explanations for the orbits with anomalous observed in the outer Solar System, and one of the ideas presented was the possibility that the so-called Planet 9 could be, in reality, a black hole the size of a grapefruit but with a mass between five and ten times greater than that of the Earth.”

Be that as it may, it seems that the nature of the mysterious source of gravity that alters the orbits of many known objects is about to be revealed. What planet or a black hole? The coming years will tell.