Astronomers to find out whether Planet X is a black hole

(ORDO NEWS) — In the coming years, scientists will be able to test the intriguing assumption that the hypothetical Planet X on the outskirts of the solar system is a black hole that formed in the first seconds after the Big Bang. If this version is confirmed, the discovery will go down in the history of science.

Paradoxically, astronomers do not need to make any extra effort to test this seductive hypothesis. It is enough that the large telescope under construction be launched on time and follow the intended observation program.

This surprising conclusion is presented in a scientific article accepted for publication in the journal Astrophysical Journal Letters. In the meantime, you can familiarize yourself with her preprint.

New planet?

Recall that a few years ago, astronomers talked about the presence of an unknown planet in the family of the Sun. The authors of this hypothesis were Michael Brown (Michael Brown) and Konstantin Batygin (Konstantin Batygin) from the California Institute of Technology. The researchers were prompted by the trajectories of small celestial bodies located on the outskirts of the solar system. Experts concluded that the gravity of an unknown body, which is several times more massive than the Earth, affects these orbits.

The hypothesis of Planet X is seductive, but not controversial. There is no unanimity among experts about whether the trajectories of small bodies are really distorted by some additional gravity, as the authors of the model insist. And even if there is additional gravity, it can be generated not by one massive object, but by many miniature ones.

Primary black holes: elusive and alluring

Nevertheless, some experts have put forward an even bolder assumption that the “object X” exists, but is not a planet, but a primary black hole. Vesti.Ru talked in detail about this version.

Recall that the primary black holes are believed to have formed in the first seconds after the Big Bang. Their existence inevitably follows from the Standard Cosmological Model, confirmed by many facts, from the scattering of galaxies to the chemical composition of stars.

Nevertheless, observers have not yet found a single similar object. And this is not surprising, because black holes are therefore called black because they do not emit light or other types of radiation.

If the primary black hole is found literally in the backyard of the solar system, it will be a startling discovery and a tremendous fortune. But how to check out this seductive version?

Flashes at the edge of the abyss

The answer to this question is given in his scientific article by two stars of the scientific world Amir Siraj and Abraham Loeb from Harvard University.

The basic idea of ​​these two very famous authors of the most different surprising hypotheses and discoveries is simple. It is generally recognized that at the farthest reaches of the solar system there is a huge accumulation of small ice bodies, known as the Oort cloud. It is from there that long-period comets come. But if beyond the orbit of Neptune there really is a black hole of planetary mass, then guests from the Oort cloud will fall on it from time to time.

The absorption of such an ice block by a space predator will be accompanied by a flash that can be seen from Earth. (We emphasize that the radiation will not be emitted by the black hole itself, which will remain black, but by the substance incident on it.)

This is how astronomers discover more massive black holes. Only usually we are talking about the absorption of huge masses of gas or the destruction of stars. But there is very little gas on the outskirts of the Solar System, and breaking the Sun into a black hole weighing 5–10 Earths is too much for it (and it’s hardly worth it to be upset). But such a “dangerous baby” will quite cope with a cometary comet.

It is not known where and it is unclear when

However, not all so simple. Firstly, the flash will still be very dim. Secondly, short-term. And thirdly, it is difficult to say in advance at which point in the sky it will occur, because the orbit of the hypothetical Planet X is known only approximately.

In other words, to record such an event, a sensitive telescope is required, which regularly surveys large areas of the sky. Meanwhile, the largest tools, on the contrary, have an extremely narrow field of view. And telescopes that regularly search the sky for flashes are usually not very sensitive.

It is very successful that the tool with the necessary characteristics will soon enter into operation. This is LSST, also known as the Vera Rubin Observatory.

A huge 8.4-meter telescope will be able to quickly take pictures of large areas of the celestial sphere. In just a week of observation, he will have time to double-examine the entire sky, and in this mode the observatory will work for several years.

All this makes the LSST an indispensable tool for finding dim flashes that occur in the unknown where and it is unclear when.

“Other telescopes are good for aiming at a known target,” Loeb explains. “But we don’t know exactly where to look for the ninth planet. We only know the vast region in which it can be located.”

According to the calculations of Loeb and Siraj, already the first year of LSST’s work on the already approved observation program will confirm or refute the hypothesis that the mysterious “object X” is a black hole.

A negative result is also a result.

Note that the search for such outbreaks is important not only in connection with the nature of Planet X, the very existence of which is still in question.

The fact is that LSST is able to detect any black hole of planetary mass located between the Sun and the boundary of the Oort cloud (and it is one hundred thousand times farther from the sun than the Earth). And if they are not found there, this in itself will become an important scientific result.

Let’s explain. Theorists are convinced of the existence of primary black holes, but they cannot say for sure how often they occur. So far, observers can help colleagues only with conclusions in the spirit of “we calculated the maximum possible number of primary black holes in the Galaxy, based on the fact that we do not see them; if there were more of them, we would have already noticed them.” Such observational constraints are important because they allow us to discard theoretical models that contradict them.

And, according to the calculations of Loeb and Siraj, the “non-discovery” of primary black holes on the LSST will impose extremely strict observational restrictions on their numbers. They will be several orders of magnitude tougher than the estimates that currently exist. So this is the case when a negative result is also a result (but a positive one, of course, would be much more interesting).

Recall that, according to the plan, the first test observations on the LSST will begin in 2021, and a full-fledged scientific program will start in 2022. So, it’s not long to wait for the discoveries.


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